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1 AN ABSTRACT OF THE THESIS OF David Wayne McAndrew for the degree of Doctor of Philosophy in Soil Science presented on February 26, 1983 Title: Soil Fertility Investigations on Soil Solution Composition Abstract approved: and Nutrition of, Sweet Corn find Anions Redacted for Privacy Dr. Thoma'. Jackson Laboratory incubation studies and field studies with sweet corn and onions were undertaken to evaluate interactions of lime, phosphorus (P), and copper (Cu). Eight soils were incubated at a constant temperature of 21 C with combinations of band placed monocalcium phosphate (MCP), ammonium sulfate (AmS), and copper sulfate pentahydrate (CSPH) fertilizers. After incubating one, three, or five weeks soil solution was removed by centrifugation from a core 3.0 cm in diameter centered on the fertilizer band. Soil solution Cu was decreased up to 8 fold when bands of AmS and CSPH contained MCP in 5 soils dominated by mineral colloids. Soil solution Cu was increased by these treatments on 3 soils dominated by organic colloids. Irrigated sweet corn field studies on a Willamette SiL with P treatments demonstrated an antagonism between banded P and leaf Cu concentration. Treatments receiving broadcast P did not show this antagonism. Depression of soil solution Cu concentration by MCP in the incubation studies, and the lack of effect of broadcast P on leaf Cu concentration leads to the conclusion that banded P causes the interaction. P-Cu interactions were not evident with onions grown on 2 soils of high organic colloid content. Lime increased yield, increased P uptake, and decreased P fertilizer requirements. A soil ph of 6 was adequate for sweet corn. Broadcast and banded P and P sources were also evaluated with sweet corn. Increasing the banded P rate from 33 to 76 kg P/ha usually increased leaf P concentrations and in most cases yield. Broadcast P

2 was superior to banded P in one June 3 planting probably due to warm soil temperature. Diammonium phosphate (DAP), MCP, ammonium polyphosphate (APP) and two TVA experimental urea phosphates (UP) were evaluated. MCP, DAP, and UP were equally effective in first year of experiments but the (UP) interacted differently with lime the second year. Applications of 11 kg Cu/ha as CSPH or 2 kg B/ha as Solubor resulted in increased leaf concentrations of Cu or B but not yield increases.

3 Soil Ferility Investigations on Soil Solution Composition and Nutrition of Sweet Corn and Onions by David Wayne McAndrew A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Completed February 26, 1983 Commencement June 1983

4 APPROVED: Redacted for Privacy Professor of Soil Science i charge of major Redacted for Privacy 1/ 4, He of Department of Soil Science Redacted for Privacy Dean of Graduate School Date thesis is presented February 26, 1983 Typed by Researcher for David Wayne McAndrew

5 ACKNOWLEDGEMENTS I wish to thank the following people who have been of invaluable assistance to me through the course of the preparation of the dissertation. Dr. T. L. Jackson, under whose supervision this extensive research project was undertaken and for suggestions and critisms during the preparation of the dissertation. Dr. Del Hemphill, without whose participation, and interest, the sweet corn field studies would not have been possible. Dr. N. W. Christensen for advice and critism throughout the course of the prepartation of the dissertation. Dr. P. J. Bottomley whose insight into methods of approaching research problems. Dr. W. McCuistin who served as the Graduate School Representative. Norman Klampe and Neil Kurth for their interest and cooperation in the onion field studies. Dave Tapley and Dean Hanson for the assistance in the laboratory. The fellow graduate students who by sharing the experience of this educational process have also influence the prepartion of this graduated student. Special appreciation must be be made to Gary Kiemnec, John Hickman, Alan Flint, Lorrie Flint, El Hadi Maatougui and a long list of participants in the sweet corn harvests. Financial support for this research was provided by the Tennesse Valley Authority, Soils and Fertilizer Division, under contact number A.

6 TABLE OF CONTENTS INTRODUCTION 1 LITERATURE REVIEW 3 Phosphorus 3 Micronutrients 8 Nutrient Interactions 10 Soil Solution 12 CHAPTER I: Soil Solution as Influenced by Phosphorus, Nitrogen and Copper Fertilizers 15 INTRODUCTION 15 MATERIALS AND METHODS 16 RESULTS 21 DISCUSSION 33 CHAPTER II: Sweet Corn Field Studies 37 INTRODUCTION 37 MATERIALS AND METHODS Sweet Corn Field Studies Sweet Corn Field Studies Sweet Corn Field Studies 45 RESULTS Sweet Corn Field Studies Sweet Corn Field Studies Sweet Corn Field Studies 68 DISCUSSION 73 CHAPTER III: Onion Field Studies on Organic Soils 78 INTRODUCTION 78 MATERIALS AND METHODS Onion Field Studies Onion Field Studies Onion Field Study 85 RESULTS AND DISCUSSION 87 SUMMARY 90 BIBLIOGRAPHY 93 APPENDIX 98

7 LIST OF FIGURES Figure I-1: Soil solution Cu and P concentrations as influenced by increasing rates of P added as MCP in fertilizer bands with AmS and CuS, a) Willamette CL; b) Labish (16% OM); c) Central Point SL. Figure 1-2: Soil solution Cu and P concentrations influenced by increasing rates of P added as MCP in fertilizer bands with AmS and CuS, a) Nekia one SiCL; b) Nekia two SiC; c) Semiahmoo muck; d) Woodburn SiCL; e) Chehalis SiCL. Figure 1-3: Soil solution P concentrations as influenced by duration of incubation with MCP, AmS and CuS, a) Willamette CL; b) Labish (16% OM); c) Central Point SL. PAGE

8 Table I-1: Table 1-2: Table 1-3: Table 1-4: Table 1-5: Table 1-6: Table 1-7: Table 1-8: Table 1-9: Table I-10: Table II-1: Table 11-2: LIST OF TABLES Classification of soils used in incubation study. Soil chemical and physical analyses data for the eight soils used in the incubation studies. Fertilizer treatments used for incubation experiments. Elemental composition and ph of soil solutions extracted from soil within the fertilizer band after incubating one, three and five weeks for Willamette soil. Elemental composition and ph of soil solutions extracted from soil within the fertilizer band after incubating one, three and five weeks for Labish soil. Elemental composition and ph of soil solutions extracted from soil within the fertilizer band after incubating one, three and five weeks for Central Point soil. Elemental composition and ph of soil solution extracted from within the fertilizer band after incubating of three and five weeks for five Western Oregon soils. Elemental composition and ph of soil solutions extracted from soil 1.5 cm away from the fertilizer band after incubating one, three and five weeks for Willamette soil. Elemental composition and ph of soil solutions extracted from soil 1.5 cm away from the fertilizer band after incubating one, three and five weeks for Labish soil. Elemental composition and ph of soil solutions extracted from soil 1.5 cm away from the fertilizer band after incubating one, three and five weeks for Central Point soil. Soil chemical analyses data for three years of sweet corn experiments on a Willamette silt loam at the North Willamette Experiment Station. Planting, sampling and harvest dates for three years of sweet corn experiments. PAGE Table 11-3: Treatments for 1981 sweet corn field experiments. 44

9 Table 11-4: Table 11-5: Table 11-6: Table 11-7: Table 11-8: Table 11-9: Phosphorus sources used in 1982 sweet corn field experiment at the North Willamette Experiment Station. Treatments used for 1982 sweet corn field experiment at the North Willamette Experiment Station. Phosphorus and Cu influence on tasselling leaf sample Cu concentration in sweet corn, experiment one Broadcast P rate and rate of banded P effects on yield of number one ears, total yield and cutoff yield of sweet corn experiment one, harvest one Broadcast P rate, broadcast Cu and banded P rate influence on yield of number one ears, total yield and cutoff yield in sweet corn experiment one, harvest one Lime effects on nutrient concentrations in tasselling leaf samples of sweet corn, experiment two Table II-10: Lime and Cu fertilization influence on tasselling leaf sample Cu concentration of sweet corn, experiment two Table II-11: Lime rate and broadcast Cu effects on total yield and cutoff yield of sweet corn, experiment two harvest one Table 11-12: Table 11-13: Table 11-14: Phosphorus source effects on leaf sample Mn and Zn 57 concentrations of sweet corn, experiment one Phosphorus source and P band rate effects on leaf 57 sample Mn and Zn concentrations of sweet corn, experiment one Broadcast and banded P effects on yields of sweet 58 corn, experiment one Table 11-15: Lime effects on leaf P concentrations, sweet corn 58 experiment two Table 11-16: Lime influence on leaf Cu concentrations, sweet 60 corn experiment two Table 11-17: Lime effects on leaf Zn concentrations, sweet corn 60 experiment two 1981.

10 Table 11-18: Lime effects on leaf Mn concentrations, sweet corn 61 experiment two Table 11-19: Lime effects on leaf Ca concentrations, sweet corn 61 experiment two Table 11-20: Broadcast and banded phosphorus effects on early 62 leaf sample P and Mn concentrations of sweet corn, experiment two planting two Table 11-21: Lime influence on uptake of P and Mn in five sweet 62 corn shoots, experiment two planting two Table 11-22: Lime influence on cutoff ratio and cutoff yield.64 for sweet corn experiment two, planting one Table 11-23: Lime influence on yields of sweet corn, experiment 64 two, planting two, harvest one Table 11-24: Lime influence on yields of sweet corn, experiment 65 two, planting two, harvest two Table 11-25: Broadcast P influence on yields of sweet corn, 65 experiment two, planting two Table 11-26: Lime and broadcast P effects on yields of sweet 66 corn, experiment two, planting two, harvest one Table 11-27: Lime and broadcast P effects on yields of sweet 66 corn, experiment two, planting two, harvest two Table 11-28: Lime and banded P effects on total yield for sweet 67 corn experiment two, planting one, harvest one Table 11-29: Phosphorus banded and broadcast Cu on nutrient 67 concentrations in sweet corn, experiment one Table 11-30: Lime, banded P and supplemental Cu addition 69 influence on yield of number one ears and cutoff from number one ears, sweet corn experiment one, Table 11-31: Lime effect on tasselling leaf sample nutrient 69 concentrations, sweet corn experiment two Table 11-32: Banded phosphorus effect on P and Cu 71 concentrations in leaf samples of sweet corn experiment two Table 11-33: Influence of banded P source on leaf concentration 71 of P, sweet corn experiment two, 1982.

11 Table 11-34: Lime and banded P effects on yields of sweet corn, 72 experiment two Table 11-35: Lime and source of banded P influence on yields of 72 sweet corn, experiment two, Table III-1: Soil characteristics and dates of seeding and 81 sampling for three years of onion experiments. Table 111-2: Fertilizer treatments used for both 1980 onion 83 field experiments. Table 111-3: Fertilizer treatments used for both 1981 onion 84 field experiments. Table 111-4: Fertilizer treatments used for the 1982 Klampe 86 onion field experiment. Table 111-5: Average nutrient concentrations and yields of 89 onion field studies. Appendix Table 1: Nutrient concentrations at two sampling dates 98 for Jubilee sweet corn, experiment one Appendix Table 2: Yield of marketable ears for Jubilee sweet 99 corn, experiment one Appendix Table 3: Analysis of variance for plant analysis and 100 yields of Jubilee sweet corn, experiment one Appendix Table 4: Nutrient concentrations at two sampling dates 101 for late Jubilee sweet corn, experiment two Appendix Table 5: Nutrient concentrations and nutrient uptake 102 of P, Cu, Zn and Mn for Jubilee sweet corn, experiment two Appendix Table 6: Yield of marketable ears for Jubilee sweet 103 corn, experiment two Appendix Table 7: Analysis of variance for plant analysis and 104 yields of Jubilee sweet corn, experiment two Appendix Table 8: Analysis of variance for plant analysis, 105 yield and uptake of P, Cu, Zn and Mn of Jubilee sweet corn, experiment two Appendix Table 9: Nutrient concentrations at two sampling dates 106 and yields of sweet corn, experiment one Appendix Table 10: Analysis of variance and error mean square 107 for Jubilee sweet corn, experiment one 1981.

12 Appendix Table 11: Sweet corn nutrient concentrations for two 108 sampling dates and yields at two harvest dates, experiment two, planting one Appendix Table 12: Sweet corn nutrient concentrations for two 109 sampling dates and yields at two harvest dates, experiment two, planting two Appendix Table 13: Nutrient concentrations and nutrient uptake 110 of P, Cu, Zn and Mn for Jubilee sweet corn, experiment two Appendix Table 14: Analysis of variance and error mean square 111 for plant analyses of Jubilee sweet corn, experiment two Appendix Table 15: Analysis of variance and error mean square 112 for yields of Jubilee sweet corn, experiment two Appendix Table 16: Analysis of variance for plant analysis, yield and uptake of P, Cu, Zn and Mn of Jubilee sweet corn, experiment two Appendix Table 17: Early leaf sample nutrient analysis of the 114 Jubilee sweet corn experiment one Appendix Table 18: Tasselling leaf sample nutrient analysis of 115 Jubilee sweet corn experiment one Appendix Table 19: Yield of marketable sweet corn from sweet 116 corn experiment one Appendix Table 20: Early leaf sample nutrient analysis of the 117 Jubilee sweet corn experiment two Appendix Table 21: Tasselling leaf sample nutrient analysis of 118 the Jubilee sweet corn experiment two Appendix Table 22: Yield of marketable sweet corn from 119 experiment two Appendix Table 23: Analysis of variance and error mean square 120 for Jubilee sweet corn, experiment two Appendix Table 24: Yield of number one ears and P concentration 121 of border rows with only lime treatments, experiment two Appendix Table 25: Sweet corn yield and nutrient concentrations of border rows with only broadcast P and Cu treatments, experiment one

13 Appendix Table 26: Sweet corn yield and nutrient concentrations 122 of border rows with only broadcast P and lime treatments, experiment two Appendix Table 27: Leaf sample nutrient concentrations and uptake yield, nutrient concentrations and uptake in bulbs plus leaves for 1980 Kurth onion experiment. Appendix Table 28: Leaf sample nutrient concentrations and uptake yield, nutrient concentrations and uptake in bulbs plus leaves and harvested yields for 1980 Kurth onion experiment. Appendix Table 29: Nutrient concentrations of onion leaves at two sampling dates for P, Cu, Zn and Mn for 1981 Kurth experiment Appendix Table 30: Nutrient concentrations and nutrient uptake 126 of P, Cu, Zn and Mn for 1981 Kurth onion experiment. Appendix Table 31: Harvested yield onions for 1981 Kurth onion 127 experiment. Appendix Table 32: Nutrient concentrations at two sampling 128 dates of onions for P, Cu, Zn and Mn for 1981 Klampe experiment. Appendix Table 33: Nutrient concentrations and uptake of P, and 129 Cu for samples take on July 18, 1981 and harvested yield onions for 1981 Klampe experiment. Appendix Table 34: Analysis of variance for 1981 Kurth onion 130 experiment. Appendix Table 35: Analysis of variance for 1981 Klampe onion 130 experiment. Appendix Table 36: Analysis of variance for plant analysis, 131 yield and uptake of P, Cu, Zn and Mn of the 1981 Kurth onion experiment. Appendix Table 37: Analysis of variance for plant analysis, yield and uptake of P, and Cu of the 1981 Klampe onion experiment. 131 Appendix Table 38: Nutrient analysis of Danvers onions planted 132 March 28, 1982, as infuenced by Cu, Zn, Mn and nitrogen fertilizers sampled when bulbs were 1 to 2 cm in diameter (July 2, 1982). Appendix Table 39: Nutrient analysis of Danvers onions planted 133 March 28, 1982, as infuenced by Cu, Zn, Mn and nitrogen fertilizers sampled when bulbs were 2 to 3 cm in diameter (August 11,1982).

14 Appendix Table 40: Yields of Danvers onions planted March 28, , as infuenced by Cu, Zn, Mn and nitrogen fertilizers.

15 SOIL FERTILITY INVESTIGATIONS ON SOIL SOLUTION COMPOSITION AND NUTRITION OF SWEET CORN AND ONIONS INTRODUCTION Soil characteristics have changed over time as a result of high rates of fertilizer materials which have been added to soils used for vegetable crop production. Soil chemical analyses for essential plant nutrient elements of soils used for vegetable production often indicate high nutrient availability. However, vegetable crops produced on these soils generally benefit from fertilizer addition, if not in yield in improved marketable grade, storage quality or uniformity of maturation. Problems have become those of-managing high fertility soils at minimum input cost for profitable crop production. Mineral soils used for sweet corn production in Western Oregon vary from high to low availability of plant nutrients. Micronutrient deficiencies have been known to occur as a result of addition of high rates of phosphorus fertilizers particularly if the soil is marginally deficient in some micronutrient. In 1978 and 1979 a survey of sweet corn fields in the Willamette Valley was conducted to determine potential nutrient imbalances in producers fields (Jackson and Bostdorf, 1979). This survey identified several sweet corn fields with Cu concentrations in leaf samples less than 5 mg Cu/kg plant material. Onion field studies conducted on a mineral soil at the Southern Oregon Experiment Station (SOES) in 1978 and 1979 with rates of banded and broadcast phosphorus with and without additional Cu indicated \ that an antagonistic influence of phosphorus on Cu concentration and 'uptake by onions was occurring (Jackson and Yungen, 1980). The demonstrated antagonism between phosphorus and copper in onions and the low Cu levels in sweet corn leaves indicated that a potential problem existed. If the antagonistic influence of phosphorus on copper also occurs in sweet corn there is the possibility that the high levels of phosphorus usually added for sweet corn production could result in an induced Cu deficiency. This antagonism could

16 2 depress yield and quality of sweet corn. Therefore it was decided to initiate a cicser study of this interaction. Additionally methods and sources of phosphorus application, influence of soil ph, Cu fertilization and planting schedule for sweet corn production were felt to be in need of investigation. The onion study at the Southern Oregon Experiment Station had been conducted on a mineral soil low in phosphorus. Commercial onion production in Western Oregon is predominately restricted to the Lake Labish and other organic soil deposits in the Willamette Valley where onion production is on high organic matter soils. Thus, the studies in southern Oregon may not be applicable to these organic soils. Therefore studies were initiated on organic soils of Lake Labish to ascertain whether the same P-Cu interaction could also be expected to occur when organic matter and soil analyses for available nutrients were high. As the studies progressed it became evident that a more thorough understanding of the influence of fertility management practices on soil nutrient availability was required. Studies to determine the influence of monocalcium phosphate, copper sulfate and ammonium sulfate fertilizer materials on nutrient concentration in soil solution were initiated to aid in the interpretation of field observations. Surface soils were collected from a variety of western Oregon locations for incubation studies of the influence of bands of fertilizer materials on nutrient concentration in extracted soil solution.

17 3 LITERATURE REVIEW Plant nutrition disorders can occur with vegetable crops due to intensive past and current fertility management practices. Nitrogen is usually added appropriately for maximum production but problems can result from phosphorus, micronutrient and amendments of lime. The interactions of phosphorus, micronutrients and lime can influence marketable yields of vegetable crops. Soil chemical analyses has not been entirely successful in predicting when nutrition disorders may occur. Monitoring with plant analyses has also been used and does aid in soil fertility management of plant nutrition. Phosphorus Utilization of soil and fertilizer phosphorus can be influenced by soil acidity, soil temperature, source and placement of phosphorus fertilizer, and the interaction of phosphorus with lime amendments. Micronutrient-phosphorus interactions are important factors influencing plant nutrition and nutrient utilization. Phosphorus Availability Indices Soil analyses procedures for phosphorus attempt to determine the soil solution P (intensity) and the ability of the soil to replenish soil solution P measured as exchangeable or soluble in a specific extracting solution (capacity). Two of the most widely employed P analyses methods are the Bray I (0.03M NH4F M HC1) and Olsen's sodium bicarbonate (0.5M NaHCO3) for acid and non-acid soils respectively. The anion in Bray I (F ) and Olsen's (HC073) extract procedures have high specificity for the exchangeable surface phosphorus from the dominate adsorption sites in acid and non-acid soils respectively. Novais and Kamprath (1978) estimated by use of green house experiments with pearl millet (Pennisetum americanum) and various soil P analyses procedures that three Coastal Plains soils from North Carolina with 64, 141, and 158 mg Bray I P/kg were adequately supplied for 1, 5, and 6 years of field corn (Zea mays) production without phosphorus additions. Yield of winter wheat (Triticum aestivum) on some western Oregon soils with up to 112 mg Bray I

18 4 P/kg was increased by a concomitant increase in the phosphorus content at mid-tillering from less than 0.15 dag P/kg plant material with the addition of 44 kg P/ha (Sullivan 1981). Low soil temperature and soil acidity were indicated to be major contributing factors to this response. Displaced soil solution has also been used to predict soil supply of P. Soltanpour et al. (1974) were able, in a growth chamber experiment, to show a good relationship between soil solution P and dry matter yield of a sorghum-sudangrass hybrid (Sorghum bicolor X S. sudanese). They concluded, however, that due to the tedious procedure for column displacement of soil solution the method was impractical for routine use. Adams, J. at al. (1982) were able to show increases in yield, extractable P and centrifuge displaced soil solution P (Adams et al. 1980) as a result of phosphorus fertilization of soils with various ph's. Plant analyses and soil analyses have improved the monitoring of nutritional status for crop production. Chemical analyses of soils that have been used for vegetable crop production usually show residual carryover of nutrients such as P or K that would be adequate for most crops. However, response to P fertilization as either, marketable grade or total yield often occurs with crops like sweet corn, snap beans and other vegetable crops. Plant analysis has been used successfully to predict or determine efficiency of fertilizer practices (Geraldson et al. 1974). Ulrich (1952) emphasized that standard times and plant parts for plant samples be adopted when plant analyses are used to predict response from fertilizers. Both plant age and plant part influence nutrient concentration. Thus, if meaningful information is to be gained by plant analyses standardization is required. Additionally plant part to be sampled for most nutrients must be actively growing to indicate current supply of nutrients (Ulrich, 1952). Geraldson at al. (1974) in a review listed common ranges for P in sweet corn of 0.18 to 0.30, 0.30 to 0.80 and 0.20 to 0.30 dag P/kg plant material for ear leaves sampled after silking, at 80% silking, and at start of silking respectively. MacKay and Leefee (1962) suggested

19 5 optimal levels of P in sweet corn as 0.34, 0.38, and 0.41 dag P/kg plant material phosphorus at the development stages of 6 to 7 leaves, tassels emerging and pollen shedding respectively. Soil Temperature Influence on Phosphorus Sutton (1969) in reviewing the effects of low soil temperature on phosphorus nutrition, listed four factors involved in inorganic P nutrition which are temperature sensitive; these are, a capacity factor, a rate factor, an intensity factor and a diffusion factor. Sutton concluded that acting together these factors resulted in both decreased P availability and decreased quantity of potentially available P. Sutton also cited work that indicated that plant growth was more restricted than P availability at low soil temperatures. Accumulation of P in the plants could occur if adequate levels of P were present in the soil, thus benefiting the plant as the temperature warmed and growth accelerated. Sheppard and Racz (1982) studied the effect of P placement and soil temperature with spring wheat (Triticum aestivum) in a growth chamber experiment. At 10 C response to band placed P was greatest but at 25 C there was evidence of P toxicity in the band. They indicated that root proliferation in the fertilizer band was the greatest at the lowest temperature. They stressed the importance of band P applications for soils that would be cold during any part of the growing season. Mack et al. (1964) with snap beans (Phaseolus vulgaris) and peas (Pisum sp.) found increases in yield with increases in soil temperature and/or P addition rate with snap bean but not with peas. Plant P concentration and uptake increased for snap bean with either increase in soil temperature from 17 to 26 C or addition of 78 kg P/ha; a similar increase did not occur in the peas grown under the same conditions. Soil Acidity and Liming Influence on Phosphorus Utilization McLean and Kamprath (1970) presented two different viewpoints for liming acid soils. McLean suggests a target soil ph of 6.5 (distilled water extract) to decrease toxic levels of Al, Mn and Fe by precipitation. This would also increase availability of Ca, Mg, P, K, S, and Cu. Kamprath, on the other hand, suggests that lime

20 6 should be added until Al, Mn and Fe are inactivated which may be at a ph of as low as 5.8 to 6.2 (distilled water extract) as long as other nutrients are in adequate supply. Adams, J. et al. (1982), working with soybeans, presented data that revealed trends of increasing soil chemical analysis of P with increasing soil ph as a result of liming at low levels of P fertilization which resulted in yield increases. Phosphorus fertilization at higher rates caused an antagonistic interaction with Zn and a decrease in the yield resulted. Liebhardt (1979) presented evidence that liming a soil to ph of 6.4 decreased corn (Zea mays) yields as compared to a ph of 5.7. Liebhardt attributed this to decreased availability of Mn and Zn. Hemphill and Jackson (1982) reported results where lime was applied for production of bush beans, carrots and lettuce. Yields of carrots and bush beans were not consistently increased when soil ph was above 5.7 while head lettuce yields were increased by liming up to a soil ph of 6.1. Decrease in toxic effects of Mn as soil ph was increased was a major factor as well as increases in availability of P and Ca. Phosphorus Sources Phosphorus is preferentially accumulated by the plant in the form of H PO4 2 although HP0 4 can be assimilated. According to Barber (1980) uptake of P follows Michaelis-Menton relationship: 1=1 x Km C + C were I = rate of uptake, I = maximum rate of uptake, C = concenmax tration in soil solution and K m = the Michaelis-Menton constant. The value of I for the H PO4 form of the orthophosphate ma x 2 2- anion is ten times greater than the I for HPO (Barber, max ). The reaction: 2- HPO4 + H H2PO4 4 pk= 7.21 at 25 C controls the proportion of orthophosphate as each species. Increasing ph from 5 to 9 decreases the proportion of H 2 P0-4

21 7 from approximately 100% to approximately 0% (Mengel and Kirkby, 1978). Phosphorus fertilizer material must be converted to the orthophosphate anion (H po (3-n)- ) n to be effective. This criteria is met by most P containing materials since soil reactions result in the conversion of complex phosphates to orthophosphates. Phosphorus fertilizers are available in many forms. The most efficient materials for vegetable crop production are those with the highest degree of water soluble P. This results in rapid increases in H2 PO4 concentration in the soil. Studies to determine the effectiveness of various phosphorus sources, in particular, orthophosphates and polyphosphates are common (Adams, 1982; Khasawneh et al. 1974; Rhue et al. 1981; Sample et al. 1979) and usually conclude either ortho- or poly- phosphates are equally effective in supplying P for plant growth. Engelstad and Terman (1980) reviewed the effects of ammonium versus calcium phosphates as P sources. Monoammonium phosphate or NH 4 containing or producing fertilizer placed with monocalcium phosphate usually resulted in beneficial effects (Miller, 1974; Engelstad and Terman, 1980). Adverse effects occur with either urea or diammonium phosphates banded near the seed as a result of increased ph near the fertilizer granule. Accumulation of NH 4 occurs causing inhibition of oxidation of NO2 and in the formation of NH 3(aq) both of which result in a toxic effect on plants. Bezdicek et al. (1971) reported that diammonium phosphate when added to a soil with a ph of 8.3 as granules with a spacing of 1.5 cm caused accumulation of 42% of the added N as NO 2 after seven days of incubation. This same material when powdered and mixed with the entire soil volume resulted in an accumulation of only 0.6% of the added N as NO2 after the same period of incubation. Release of NH3(g) was also indicated to be a potential problem if urea or diammonium phosphate were placed with or near the seed resulting in seedling injury, particularly in non-acid soils. Bennet (1972) suggested that the toxic effect of ammonium was as an uncharged aqueous form, NH This form of nitrogen reportedly 3(aq)'

22 8 hinders photosynthetic phosphorylation, ferricyanide reduction and other metabolic reactions. Placement of Phosphorus Fertilizers Two basic placement methods can be used for fertilizer material, band placement which restricts fertilizer soil contact or broadcast placement which does not restrict fertilizer soil contact (Engelstad and Terman, 1980). Combination of broadcast fertilizer incorporated with the soil plus a band of fertilizer with or near the seed has been termed a "pop-up" fertilizer application. The "pop-up" method results in early vigor as a result of the band treatment allowing for root contact with nutrients in the seedling stages of growth plus the broadcast fertilizer application is less labor intensive which can be an important concern during seeding operations. Peterson et al. (1981) suggest that the relative effective advantage of band versus broadcast phosphorus may be from 3:1 to 1:1 for low and medium soil test soils respectively. Barber (1980) presented evidence that placing phosphorus fertilizer in surface applied strips 5 to 10 cm wide every 70 cm on the soil surface and then plowing them in was more effective for grain corn production than either broadcast or banded placement. Sutton (1969) suggested a band placement of P fertilizer was advantageous in cold soils due to the supply of a more concentrated zone of high energy P which resulted in more vigorous early growth. Micronutrients Copper (Cu), zinc (Zn), manganese (Mn), iron (Fe), and boron (B) are five elements supplied from the soil that are required in small amounts for plant growth. Availability of these nutrients can be restricted either as a result of soil chemical reactions or due to low total abundance in the soil parent material or leaching from the surface soil. Cultural practices such as land leveling which results in exposure of calcareous subsoil horizons where high soil ph decreases availability of micronutrients can cause micronutrient deficiencies. Soil organic matter plays an important role in the soil chemistry of micronutrients. The availability of Cu, Zn, Fe, and Mn from

23 9 soil organic matter, which contains natural chelating characteristics is greater than the availability from inorganic soil minerals. Thus organic matter chelation has a positive influence in most cases. The availability of Cu can be depressed as soil organic matter content increases. This affect is due to the strong binding of Cu with organic matter which Bloom and McBride (1979) felt was a covalent bonding whereas most metals are bonded in noncovalent bonds to charged sites in the organic matter. This sequestering of Cu results in Cu deficiencies when crops are grown on organic soils without the addition of fertilizer Cu. Copper, Zn and B deficiencies can readily be corrected by addition of fertilizer materials containing the micronutrient of interest (Gilkes, 1981; Murphy and Walsh, 1972). Manganese deficiency has not been as successfully corrected by Mn fertilization due to soil reactions which rapidly decrease availability of Mn fertilizer. Banding an acidifying fertilizer such as ammonium sulfate either with or without Mn fertilizer has been shown to be an effective practice to correct Mn deficiency (Jackson and Carter, 1976; Petrie, 1982). Placement method and carrier studies of most Cu, Zn, and B fertilizers have usually shown that broadcast applications either as granules or in a spray solution to the soil surface subsequently mixed with the soil by discing, rotovating or plowing as effective treatments for increasing availability of micronutrients. Manganese and iron do not follow this generalization due to the soil reactions which rapidly render broadcast applications of these nutrients unavailable. This placement was particularly effective for inorganic micronutrient fertilizers (Brown and Krantz, 1966; Gilkes, 1981; McAndrew, 1980). Micronutrient status can be assessed by either soil chemical analysis or plant analysis. Soil chemical analysis has the advantage of determining nutrient requirements prior to crop establishment. Procedures have been developed which measure the soil solution plus exchangeable and/or soluble micronutrients present in a soil (Lindsay and Norvell, 1978; Parker, 1981; Reisennauer et al. 1973; Viets and Lindsay, 1973). Based on correlation of soil analyses results

24 10 with responses to micronutrient fertilization, micronutrient recommendations for crop production can be made. Plant analysis for micronutrients usually require the ashing of a plant material, such as a particular leaf at a defined growth stage, either in a muffle furnace or in a wet digest such as nitricperchloric acid mixture. Once sufficient data are collected for correlation of plant nutrient concentration with growth responses, recommendations for micronutrient fertilization can be made (Geraldson et al., 1973). Plant analyses can be used for growing season adjustments in fertility programs but it is more likely that this information will be of benefit for the following growing season's crop production. Nutrient Interactions Interactions between nutrient elements can be either synergistic (beneficial) or antagonistic (detrimental) to plant growth. Synergistic effects are when two or more factors benefit to a greater extent than would be expected from merely an additive effect. Antagonism occurs when combinations of factors (nutrients) decrease availability, uptake or utilization of nutrients which did not occur when the factors act individually (Murphy et al., 1981; Olsen, 1972). Phosphorus-Micronutrient Interactions Murphy et al., 1981 reviewed phosphorus-micronutrient interaction studies and concluded that antagonistic interactions usually occur when there is an over supply of phosphorus or when micronutrients are initially marginally deficient or deficient. Factors which exacerbate the antagonistic interactions are; soil ph, low soil temperature, and crop requirement for and/or inability to accumulate micronutrients. Adams, J. et al. (1982) reported an antagonistic interaction between lime and phosphorus with zinc. This antagonism was evident in both soil chemical analysis and plant tissue concentration of Zn. At low levels of P fertilization, soil chemical analysis of Zn was also depressed by lime application but this did not result in the de-

25 11 pression of yield even though plant tissue Zn concentration decreased. Substantial research has occurred in recent years as to the nature of the interaction between phosphorus and zinc. A plausible physiological function that involves both phosphorus and zinc has recently been presented. Welch et al. (1982) have provided evidence for a role for zinc in membrane function. Lack of adequate zinc resulted in a decrease in integrity of membranes such that control of movement of P and Cl in or out of the roots was lost. High solution P levels resulted in toxic accumulation of P, particularly in older leaves as P moved in the transpiration stream. Other researchers have shown that Zn deficiency induced P toxicity (Christensen and Jackson, 1981; Jackson and Carter, 1976; Loneragan et al. 1982) Phosphorus-Nitrogen Interactions Ammonium or ammonium producing nitrogen fertilizer added in a band with phosphorus fertilizer usually benefits the uptake of P by plants (Miller, 1974). This affect is not attained when nitrate (NO3) forms of N are used. The three major causes of this interaction were reviewed by Miller (1974). Firstly a decease in the ph in the vicinity of the roots as H+ are excreted to maintain cation balance in the root. This excretion of H+ both increases the solubility of phosphorus but additionally increases the proportion of - anion. Secondly root growth and proliferation in the fertilized zone usually increased resulting in a P present as the H2PO4 expanded root surface area available for P assimilation. A physiological change in the P absorbing capacity of the roots was also felt to occur in the presence of the NH+ cation. Nitrification of ammonium in the soil solution by Nitrosomonas and Nitrobacter to form NO 3 and H+ also occurs thus decreasing soil ph and increasing solubility of some nutrients.

26 12 Soil Solution Soil particles are surrounded by an aqueous phase which containing soluble fractions of soil minerals and soil gases (Adams, 1974). It is from this solution that soil flora and microflora derive most essential mineral elements. Soil solution concentrations of Ca, Mg, K, Na, N, Cl, S, HCO3 in are relatively high. Early attempts to collect "intact soil solution" and determine concentrations of these components were successful (Mengel and Kirkby, 1979; Russel, 1973). Nutrients such as P, Cu, Zn, Mn, Fe, B, and Mo are present in low concentrations making detection of these elements in soil solution more difficult. Sampling soil solution in situ is not possible. Therefore all measurements of soil solution have been made on samples extracted from the soil. Adams (1974) reviewed methods for obtaining soil solution samples. Five procedures were listed; suction, displacement, compaction, centrifugation, and molecular adsorption. Displacement and centrifugation procedures have been used extensively in recent years. The other procedures have been discarded due to the inability of obtaining consistent and reliably unaltered soil solutions. Displacement of soil solution consists of placing a soil with moisture content between air dry and field capacity in a column, then adding another liquid on the soil surface. This causes the added liquid to diffuse down the column and displace the original soil solution (Adams, 1974). The soil solution so displaced is collected at the bottom of the column in some container and sealed to prevent air contact. The appearance of the displacing liquid at the bottom of the column can be identified by the use of colored dyes in the displacing solution. Additionally solutes added to the displacing solution such as KCNS which can be detected by addition of a drop of a FeCl3 containing solution to form red colored FeCN 2+ or a reaction such as the iodoform reaction with ethanol if that was the displacing liquid. The solution obtained from soil by the displacement procedure has been shown to be the intact soil solution (Adams, 1974). The column displacement method does suffer from some serious drawbacks, particularly the length of time required to displace the

27 13 soil solution. Adams (1974) indicated that 25% to 75% of soil solution could be displaced in an 8 hour period. Some soils may require 2 or 3 days for displacement, particularly if they are excessively compacted. centrifugation. Soil solution can also be removed from a soil by use of Centrifugation has the advantage of being simple and quick. Several methods have been presented (Adams et al., 1980; Dao and Lavy, 1978; Davies and Davies, 1963; Petrie, 1982; Soon and Miller, 1977; Yamasaki and Kishita, 1972) all of which allow for soil solution to flow from the bottom of one compartment in a centrifuge tube or apparatus to another compartment. Most of the methods have a physical separation -of soil solution obtained from the compartment which holds the soil to prevent the reabsorption of the solution by the soil. Adams et al. (1980) compared the following three methods of obtaining soil solution; column displacement, centrifugation, and centrifugation with the use of CC1 4 as an immiscible liquid (Mubarak and Olsen, 1976). They found that all Three methods resulted in very similar solutions and concluded that all three methods displaced soil solution. Petrie (1982) used a BaSO4 powder with 50%, 100%, or 150% water which was centrifuged and found that the soil centrifuge method extracted a solution having 1.6 to 2.0 mg Ba/kg of solution. Calculated concentration of Ba in equilibrium with BaS0 4 at the temperature of the extraction was 1.4 mg Ba/kg of solution. Petrie concluded that at least for this mineral this extraction procedure did not significantly alter equilibrium. Fertilizer additions to soils influence the concentrations of the added elements as well as levels of indigenous elements in the soil solution (Adams, 1974; Adams, J., et al., 1982; Adams et al., 1980; Friesen et al., 1980; Petrie, 1982; Yamasaki and Kishita, 1972). Yamasaki and Kishita (1972) added different potassium salts to soil samples and after incubating at 5 C for one week found increased levels of K as well as Ca, Mg, Na, Al, and H in soil solution. Petrie (1982) reported experiments in which addition of nitrogen or phosphorus fertilizer materials increased the Mn

28 14 concentration in soil solution. Adams, J., et al. (1982) presented data from long term field experiments which clearly indicated decreases in soil solution Zn concentrations as rate of lime or phosphorus were increased. Adams (1982) in an incubation study with monocalcium phosphate (MCP) and diammonium phosphate (DAP) found that these two phosphorus fertilizers had markedly opposite influences on the soil solution activity of Ca. The MCP increased the activity of Ca whereas the DAP decreased Ca activity. Soltanpour et al. (1974) were able to show a highly significant relationship between soil solution P and plant uptake of P in an experiment comparing various soil extraction procedures for predicting P requirements.

29 15 CHAPTER I Soil Solution as Influenced by Phosphorus, Nitrogen and Copper Fertilizers INTRODUCTION Soil solution is the aqueous phase of the soil consisting of soil water and water soluble fractions of soil minerals, soil gases and soil organic matter. This solution is the key to life for all soil organisms since flora and microflora obtain from soil solution all the required water, mineral nutrients and for some organisms oxygen and organic nutrients. Concentration of most inorganic nutrients in the soil solution is controlled by the dissolution of sparingly soluble salts. Usually when the solubility of the mineral which controls soil solution concentration of an ion is exceeded precipitation of that mineral occurs. This process occurs whether the solubility is exceeded by fluctuations in the soil environment or by the addition of supplemental amounts of an ion. The reverse of this is also true, so that when the concentration of an ion is less than the concentration which would be in equilibrium with the mineral which controls solubility dissolution occurs. Dissolution also occurs if the ions are being removed from the soil solution; for example when living organisms remove nutrients for growth or when percolating water removes dissolved ions. The objective of these studies was to investigate the influence that banded additions of monocalcium phosphate (MCP), ammonium sulfate (AmS), copper sulfate pentahydrate (CSPH) and duration of incubation would have on soil solution ph and concentrations of P, Cu, Mn, Zn, Ca, Mg, and K. The influence of soil and soil management were also felt to be important criteria to be studied. Eight soils were collected for the incubations either differing in soil classification or past management practices.

30 16 CHAPTER I MATERIALS AND METHODS Surface soil samples were collected from eight sites for the incubation studies, 3 for experiment one and 5 for experiment two. All soils were sieved in the field to pass a 8 mm screen and placed in polyethylene bags to maintain field moisture content. Classification of the eight soils used are listed in Table I-1. Soils used in experiment one were the Willamette, Labish and Central Point. Experiment two consisted of the remaining five soils. The two Nekia soils had different cropping histories, Nekia one had been in row crop production and Nekia two had been used for grass seed production. The chemical and physical analyses for the eight soils are listed in Table 1-2 with analyses by Oregon State University, Soil Testing Laboratories using chemical analyses methods outlined by Berg and Gardner (1978) and hydrometer particle size analyses. Fertilizer treatment levels which would approximate fertilizer concentrations in bands based on a 76 cm row spacing as in the sweet corn field experiments were used. Treatments 5 to 8 in Table 1-3 were used for both experiments, whereas treatments 1 to 4 were used only in experiment one. Samplings were made after incubating one, three and five weeks for experiment one and after three and five weeks for experiment two. A randomized complete block design was used for all soils except the Labish soil which was in a completely randomized design with three replicates per sampling date. All incubations were initiated by placing the fertilizer material in narrow bands at approximately 4 cm from the soil surface in boxes that measured 60 cm by 40 cm for experiment one and 40 cm by 15 cm for experiment two. Sufficient deionized water was then added to bring each soil to field capacity. Soil surfaces were covered with polyethylene to maintain moisture but yet to allow for CO 2 and 0 2 diffusion. Soil solution was extracted from the samples by the method described by Petrie (1982). Soil samples were packed into 12 or 15

31 17 Table I-1: Classification of soils used in incubation study. Designation Willamette Labish Classification Willamette, silt loam, fine-silty, mixed, mesic, Pachic Ultic Argixerolls Labish, silt clay loam, fine, montmorillonitic, acid, mesic, Cumulic Humaquepts Central Point Nekia One Nekia Two Semiahmoo Woodburn Chehalis Central Point sandy loam, coarse-loamy, mixed, mesic, Pachic Haploxerolls Nekia silt clay loam, clayey, mixed, mesic, Xeric Haplohumults Nekia silt clay loam, clayey, mixed, mesic, Xeric Haplohumults Semiahmoo muck, euic, mesic, Typic Medisapists Woodburn silt loam, fine-silty, mixed, mesic, Aquultic Argixerolls Chehalis silt clay loam, fine-silty, mixed, mesic, Cumulic Ultic Haploxerolls

32 18 Table 1-2: Soil chemical and physical analyses data for the eight soils used in the incubation studies. Soil Series ph Pt Ca Mg K CEC 4 Cu Mn Zn cmol/kg pmol/kg Willamette Labish Central Point Nekia one Nekia two Semiahmoo W000dburn Chehalis Organic Field Matter Capacity Sand Silt Clay Texture dag/kg Willamette CL Labish Central Point SL Nekia one SiCL Nekia two SiCL Semiahmoo Woodburn SiCL Chehalis SiCL t Conversion factors: cmol P/kg to mg P/kg multiply by 310; cmol Ca or Mg/kg to meq Ca or Mg/100 g multiply by 2; cmol K/kg to meq K/100 g multiply by 1; pmol Cu, Mn or Zn/kg to mg Cu Mn or Zn/kg multiply by , or respectively; dag/kg to % multiply by 1. 4 CEC determined with NH4 as saturating cation using ammonium acetate buffered at a ph of 7.0.

33 19 Table 1-3: Fertilizer treatments used for incubation experiments Treatmentt Number Designation Phosphorus Nitrogen Copper kg P/ha kg N/ha kg Cu/ha (g P/m row) (g N/m row) (g Cuim row) 1 P N Cu P 0 N 0 Cu (3.4) P N Cu 33 (2.5) 45 (3.4) 0 I 0 4 P N Cu 76 (5.8) 45 (3.4) P N Cu (0.8) P N Cu (3.4) 10 (0.8) P N Cu 33 (2.5) 45 (3.4) 10 (0.8) I I 8 P N Cu 76 (5.8) 45 (3.4) 10 (0.8) 2 1 t Treatments applied as reagent grades of monocalcium phosphate monohydrate, ammonium sulfate, and copper sulfate pentahydrate. Rates are based on fertilizer in a bands 76 cm appart as in the sweet

34 20 ml polycarbonate centrifuge tubes which had glass wool covering two small holes drilled in the bottom. The tubes were then placed in 50 ml polycarbonate centrifuge tubes and spun at 12,000 rpm in a Servall SS-34 centrifuge head for 45 minutes. Phosphorus was determined by the molybdate-vanadate method (Jackson 1958), all cations by flame atomic absorption and ph with a combination electrode. All samples were refrigerated as soon as they were obtained until they were analyzed, which was usually within 24 hours. Analysis of variance was performed on all data collected. Incubation Experiment One Soil samples were obtained by cutting out the banded zone, trimming away any soil from greater than 4 cm from the center of the band and discarding it. Soil greater than 1.3 cm but less than 4 cm from the center of the band was collected as the adjacent to band sample. All soil from within 1.3 cm of the band was termed the fertilizer band. Prior to placement in the polycarbonate centrifuge tubes for soil solution removal, all soil samples were thoroughly mixed by hand. Incubation Experiment Two A core of soil 3.0 cm in diameter centered on the fertilizer band was removed to obtain the sample for soil solution removal. This sample was thoroughly mixed prior to placement in the polycarbonate centrifuge tubes.

35 21 CHAPTER I RESULTS and Soil solution ph and concentrations of P, Cu, Mn, Zn, Ca, Mg, K as influenced by band placement of monocalcium phosphate (MCP), ammonium sulfate (AmS), and copper sulfate pentahydrate (CSPH) were measured for three soils in experiment one and five soils in experiment two. All of the nutrients measured were influenced by the band fertilizer treatments, most often as increased concentration in soil solution of the nutrients. Within the Fertilizer Band Phosphorus and copper concentrations in soil solution from within the fertilizer band increased when MCP and CSPH were banded compared to treatments which did not contain these elements (Tables 1-4, 1-5, 1-6, 1-7). AmS in the fertilizer band increased soil solution concentrations of all nutrient elements except P and Cu. Soil solution ph was initially increased in some soils as a result of addition of AmS with or without CSPH but decreased with five weeks incubation time for all but the Woodburn soil. The plus phosphorus treatments without added CSPH tended to increase soil solution Cu concentrations for the three soils used in experiment one (Tables 1-4, 1-5, 1-6). Zinc and Mn concentrations in soil solution tended to decrease by the fifth week of incubation when MCP was in the fertilizer band and was incrementally lower at P 76 compared to P33. MCP in the fertilizer band at P 33 or P 76 decreased soil solution ph in all soils except the Woodburn soil. However, with the Woodburn soil which had a soil ph of 4.8 (distilled water) banded MCP increased soil solution ph. The eight soils were in two groups with respect to the effect banded MCP on soil solution Cu concentration when CSPH was added. The mineral group of soils, in which clay minerals dominate the exchange characteristics were the Willamette, Nekia one, Nekia two, Chehalis, and Woodburn soils. The organic group of soil in which organic colloids dominate the exchange characteristics were the of

36 22 Table 1-4: Elemental composition and ph of soil solutions extracted from soil within the fertilizer band after incubating one, three and five weeks for Willamette soil. UM --TREATMENTS SOIL SOLUTION P N Cu oft P Cu Mn Zn Ca Mg WEEK ONE kg/ha- mm um mm < < < < LSO(P=0.0;) NS SEM(14df)' SIGNIFICANCE ** ** ** ** ** WEEK THREE < < < < LSD(P=0.0) SEM(14df) SIGNIFICANCE 5 * ** ** ** * ** ** ** WEEK FIVE < < , < < ,80(P=0.05) NS SEM(14df)' SIGNIFICANCE' * ** ** ** ** ** ** tfertilizer treatments were applied as reagent grades of monocalcium phosphate,?mmonium sulfate, and copper sulfate pentahydrate. Standard error of the mean, 14 degrees of freedom. F ratio significant at P.0.05, *; F ratio significant at P.0.01, **.

37 23 Table 1-5: Elemental composition and ph of soil solutions extracted from soil within the fertilizer band after incubating one, three and five weeks for Labish soil = ===== TREATMENTS -- SOIL SOLUTION P N Cu ph P Cu Mn Zn Ca Mg WEEK ONE kg/ha- mm PM mm LSD(P.0.0;) NS SEM(15d SIGNIFICANCES * ** ** ** ** ** ** WEEK THREE ,5 LS0(P=0.(T SEM(16df) SIGNIFICANCE * ** ** 4* * ** ** ** WEEK FIVE LSD(P=0.0;) SEM(16df)' SIGNIFICANCES ** ** ** * * ** ** * ** tfertilizer treatments were applied as reagent grades of monocalcium phosphate, Ammonium sulfate, and copper sulfate pentahydrate.,standard error of the mean, 16 degrees of freedom. ) 7 ratio significant at P=0.05, *; F ratio significant at P=0.01,

38 24 Table I-6: Elemental composition and ph of soil solutions extracted from soil within the fertilizer band after incubating one, three and five weeks for Central Point soil. === ==...=======..*===..=.=====*=.=..=====.===.=..=...=.=...====.= --TREATMENTS.-- SOIL SOLUTION P N Cu ph P Cu Mn Zn Ca Mg K *.=*=====...==...*==.==...=.==.===...==*.=*=..*=.==...===..========...====.:====== WEEK ONE kg/ha mm PM ml, < < < < LSD(P=0.4) NS NS SEM(14df) SIGNIFICANCE 5 ** ** ** ** ** ** WEEK THREE < < < < LSD(P=0.(T NS SEM(14df) SIGNIFICANCE ** ** ** ** ** WEEK FIVE ISD(P=0.05.) NS SEM(14df)' SIGNIFICANCES ** ** ** ** ** ** ** IFertilizer treatments were applied as reagent grades of monocalcium phosohate, immonium sulfate, and copper sulfate pentahydrate. Standard error of the mean, 14 degrees of freedom. 5 F ratio significant at P.0.05, *; F ratio significant at P=0.01, **.

39 Table 1-7: Elemental composition and pfl of soil solution extracted from soil within the fertilizer band after incubating three and five weeks for five Western Oregon soils. --T8EATMENT 1 SOIL SOLUTION WEEK 3 O N Cu p11 P Cu Ma Zn Ca Mg K ph P... Cu WEEK 5- Mn Zn Ca Mg kg/ha mm PM M mm PM sin Nekia One O O L.S0(P=0.0) NS 1.6 NS 13 NS NS MSE(641) S SIGNIFICANCE ** ** ** ** ** ** * * ** * ** ** Nekia Two O O I LSD(P=0.0) NS NS 1.2 NS 31 NS SE(6df) SIGNIFICANCE 1 ** *k ** * ** ** ** * ** ** ** * Semiahmoo O O LSD(P=0.q5) NS MSE(6df) S SIGNIFICANCE ** ** * ** * ** ** ** ** ** ** ** ** ** ** Woodburn O < < O < < ' LSO(P=0.0) MSE(6df) SIGNIFICANCE i ** ** * ** ** ** ** ** ** * * ** S ** ** Chehalis (I < II < O < < (( LS0(P=0.10) NS NS MSE(6df) SIGNIFICANCES ** ** ** ** ** ** ** ** ** ** ** ** ** Treatments applied as reagent grades of monocalcium phosphate, acunonimn sulfate, and copper 1 Mean square for error, 4 treatments, 3 replicates and 6 degrees of freedom. F ratio significant at P=0.05, *; F ratio significant at P=0.01, **. sulfate pentahydrate.

40 26 Labish, Central Point, and Semiahmoo soils. The Central Point soil is a mineral soil but the low clay content and relatively high organic matter content result in its behavior in the incubation study as if it were an organic soil. MCP plus CSPH fertilization of the mineral group resulted in depression of soil solution Cu in the fertilizer band as soil solution P increased with increased rate of MCP (Figure I-la, I-2a,b,d,e). The organic group increased in soil solution Cu concentration as soil solution P increased with increased rate of MCP (Figure I-lb,c, I-2c). Soil solution P concentration declined with incubation duration for all soils at both rates of MCP addition (Figure 1-3, Table 1-7). Adjacent to Fertilizer Band Nutrients in soil solution from soil adjacent to the fertilizer band were determined in experiment one only (Tables 1-8, 1-9, I-10). Calcium, Mg, K, Mn, and Zn soil solution concentrations in the adjacent to fertilizer band samples increased with the addition of AmS in the fertilizer band and with incubation period for the plus AmS treatments. Soil solution ph adjacent to the fertilizer band samples decreased in most cases. This decrease was significant with the addition of AmS and AmS plus MCP in the fertilizer band. Monocalcium phosphate had very little influence on soil solution concentrations of nutrients other than P and ph adjacent to the fertilizer band sample. Copper concentration tended to increase in the adjacent to the fertilizer band samples when CSPH was in the band. These results for P and Cu could have been affected by contamination from the band but every attempt was made to minimize that possibility.

41 A S 1 WEEK 3 WEEKS 5 WEEKS PHOSPHORUS (TOTAL SOLUBLE P mm) Figure I-1: Relationship of soil solution Cu and P concentration with increasing rates of P added as MCP in fertilizer bands with AmS and CuS, a) Willamette CL; b) Labish (16% OM); c) Central Point SL.

42 28 80 A WEEKS WEEKS PHOSPHORUS (TOTAL SOLUBLE P mm) Figure 1-2: Relationship of soil solution Cu and P concentrations with increasing rates of P added as MCP in fertilizer bands with AmS and CuS, a) Nekia one SiCL; b) Nekia two SiC; c) Semiahmoo muck; d) Woodburn SiCL; e) Chehalis Si CL.

43 w P1 *--4, P2 15 B P1 P TIME (WEEKS) Figure 1-3: Soil solution P concentrations as influenced by duration of incubation with MCP at two rates in bands including AmS and CuS, a) Willamette CL; b) Labish (16% OM); c) Central Point SL.

44 30 Table 1-8: Elemental composition and ph of soil solutions extracted from soil 1.5 cm away from the fertilizer band after incubating one, three and five weeks for Willamette soil. =*****.=.***.m.=.=.... =======.****=.****** **===.. ======.==*====*******=*.** --TREATMENTS -- SOIL SOLUTION N Cu ph P Cu Mn Zn Ca Mg mm***..****.*=. *****..=======...***********=.= WEEK ONE kg/ha- mm um mm < < < < LS0(1)=0.T NS NS SEM(14df) SIGNIFICANCE ** ** ** ** ** WEEK THREE < < < < < < LS0(P=0.0;) NS NS 3.6 NS SEM(14df) SIGNIFICANCE ** ** ** * ** WEEK FIVE < < < < < LSD(P=0.0;) NS NS SEM(14df) SIGNIFICANCE ** ** ** ** ** ** t Fertilizer treatments were applied as reagent grades of monocalcium phosphate, fmmonium sulfate, and copper sulfate pentahydrate. Standard error of the mean, 14 degrees of freedom. F ratio significant at P=0.05, *; F ratio significant at P=0.01, **.

45 31 Table 1-9: Elemental composition and ph of soil solutions extracted from soil 1.5 cm away from the fertilizer band after incubating one, three and five weeks for Labish soil. ============ ====... =... --TREATMENTS t -- SOIL SOLUTION P N Cu ph P Cu Mn Zn Ca Mg WEEK ONE kg/ha- mm um mm LSD(P=0.05) NS 0.13 NS NS NS NS SEM(16d0' SIGNIFICANCE s ** ** WEEK THREE LSD(P=0.T NS 0.20 NS MS MS SEM(16df) SIGNIFICANCE ** ** WEEK FIVE LSD(P=0.05,) SEM(16df) SIGNIFICANCE 5 ** ** ** ** t Fertilizer treatments were applied as reagent grades of monocalcinm phosphate, immonium sulfate, and copper sulfate pentahydrate. Standard error of the mean, 16 degrees of freedom. 5 F ratio significant at P=0.05, *; F ratio significant at P=0.01, **.

46 32 Table I-10: Elemental composition and ph of soil solutions extracted from soil 1.5 cm away from the fertilizer band after incubating one, three and five weeks for Central Point soil.... = t =3333_ TREATMENTS'-- SOIL SOLUTION P N Cu ph P Cu Mn Zn Ca Mg ===3.33=33===... 3=====.3====.33====== 33=3===== ============3======3====.3=33=3 WEEK ONE kg/ha mm um mm < < < < LSD(P=0.0) NS NS NS NS SEM(14df) SIGNIFICANCE 3 ** ** ** ** WEEK THREE < < < < LSD(P=0.0;) NS SEM(14df) SIGNIFICANCE ) ** ** ** ** ** ** WEEK FIVE LSD(P=0.0;) n SEM(14df) SIGNIFICANCE' ** ** ** ** ** ** ** ** ========.333=333===.3=33 ====== ===3=33.25===.3===3========3=3====. 3=33=3 == rfertilizer treatments were applied as reagent grades of monocalcium phosphate, ommonium sulfate, and copper sulfate pentahydrate. Standard error of the mean, 14 degrees of freedom. ratio significant at P=0.05, *; F ratio significant at P=0.01, **.

47 33 CHAPTER I DISCUSSION Nutrient concentrations in soil solution from the check treatments of experiment one and experiment two in the fertilizer bands and adjacent to the fertilizer band for experiment one were within the ranges reported in the literature for unfertilized soil samples (Adams, 1974; Adams, 1980; Adams, 1982; Adams, J. et al., 1982; Petrie, 1982). Ammonium sulfate in the fertilizer band in soils used in both experiments resulted in increased soil solution concentrations of most non added nutrients in or adjacent to the fertilizer band. Petrie (1982) at much lower rates of AmS addition also demonstrated increases in soil solution concentrations of Mn within fertilizer bands after one week of incubation but this increased concentration declined with incubation duration. Experiments evaluating fertilizer influence on soil solution composition usually have involved mixing the fertilizer throughout the soil sample, thus simulating a broadcast application of nutrients (Adams, 1982; Adams et al., 1980; Adams, J. et al., 1982; Soltanpour et al., 1974; Yamasaki and Kishita, 1972). The more recent development of centrifuge equipment that can withstand the stress of high speed centrifugation of soil samples has made it feasible to determine nutrient concentrations in fertilizer bands or small zones such as the rhizocylinder (Soon and Miller, 1977). The eight soils used in experiments one and two were grouped into two categories, mineral and organic, as a result of the influence MCP and rate of P on soil solution Cu concentration in the presence of CSPH and AmS. The soil solution Cu concentration in the mineral group decreased with increasing P rates. The organic group had increased soil solution Cu concentration with increasing rates of P. The major difference in soil composition that might account for the opposite influence of P in the two groups is the proportion of soil colloids that were mineral versus organic in the two groups.

48 34 The two organic soils are dominated in their characteristics by the organic matter fraction. The Central Point soil is a mineral soil but the organic fraction in that soil dominates the colloids due to the low clay content, low surface area available in the other soil size fractions, and the relatively high organic matter content. The mineral group would have the majority of the active colloids as mineral surfaces, both due to higher clay and lower organic content as compared to the organic group. The magnitude of the depression of soil solution Cu by increasing rate of P addition in the mineral group was much greater, as much as 7-8 times decrease in Cu concentration at P 76 as compared to P 0' than the magnitude of the increase of soil solution Cu by this treatment in the organic group. A maximum of 4-fold increase in soil solution Cu concentration occurred in the Labish soil with P 33 after one week of incubation. This was an extreme case since most other determinations resulted in a 1 to 2-fold increase in soil solution Cu concentrations with increasing P band rates for the organic soil group. These observations may help to clarify the responses that were found in field experiments with sweet corn and onions. Sweet corn P had decreased Cu concentrations and in some cases decreased Cu uptake compared to treatments which received lower rates of P grown in field experiments on a Willamette CL at high rates of fertilizer fertilization (Chapter II of this thesis). Onions grown on either Labish or Semiahmoo muck did not respond to P fertilization nor did fertilization influence onion Cu concentrations (Chapter III of this thesis). Yamasaki and Kishita (1972) incubated three soils with K 2 SO 4 and KC1 for one week after which soil solution was extracted by centrifugation. Their results indicated that soil solution concentrations of Ca, Mg, Na, Al, H, K, SO and Cl were increased 4 ' by the addition of either fertilizer material. Adams et al. (1980) obtained similar results in an incubation experiment with four soils. A combination the fertilizer materials, potassium chloride, ammonium nitrate, MCP, and magnesium sulfate, altered soil P

49 35 solution composition as obtained by three soil solution extraction procedures. The current study demonstrates the same phenomenon with the most noteworthy change being the changes in Ca and Mg concentrations in soil solution in all soils at the first determination for all treatments with bands of AmS. Manganese concentrations in soil solutions from all soils also increased as a result of AmS fertilization with the highest concentrations usually measured after five weeks of incubation. Adams (1982) incubated soils of varying lime treatments with MCP and DAP. Opposite effects of these materials on soil solution Ca activity were demonstrated regardless of lime rate. The MCP increased soil solution Ca activity whereas the DAP decreased soil solution Ca activity. Petrie (1982) using various N and P fertilizer sources found differential responses in soil solution nutrient concentrations to each source and/or combination of sources. These types of differences were found in the current study. Copper fertilization alone in some but not all soils increased soil solution Ca concentrations, MCP decreased soil solution Zn and Mn concentrations in some soils. Fertilizer materials which are highly soluble in water will alter soil solution concentrations of nutrients and non nutrients in and adjacent to fertilizer bands. Ammonium sulfate is such a material. This alteration of soil solution composition may be of considerable duration, as in these experiments where after five weeks of incubation soil solution concentrations of some nutrients were increasing with respect to earlier determinations. Adams, J. et al. (1982) reported data for soil solution from residual fertilizer experiments on two Ultisols in Alabama. Shifts in soil solution concentrations of nutrients occurred as a result of fertilizer treatments from previous years. Examinations of soil solution appears to be a very viable method of monitoring the effects of soil fertility practices on the soil. The centrifugation procedure can be utilized to measure influences of practices such as band versus broadcast applications of fertilizers

50 36 as well as to ascertain possible factors responsible for variable responses to management practices in field situations. Comparison between the soil chemical analyses and the soil solution nutrient concentrations in these studies as influenced by fertilizer additions are not valid. The soil chemical analyses methods to determine nutrient availability measure soil solution concentrations plus readily available nutrients. Comparison of the magnitude of the changes in soil solution nutrient concentrations as influenced by the fertilizer treatments between the eight soils used are also of limited use. The various soil used have different buffering characteristics with regard to the applied nutrients.

51 37 CHAPTER II Sweet Corn Field Studies INTRODUCTION A survey of commercial sweet corn fields in 1978 and 1979 identified low Cu concentrations in leaf samples as a potential yield limiting problem (Jackson and Bostdorf, 1979). Experiments with onions at the Southern Oregon Experiment Station in 1978 and 1979 had demonstrated an antagonism between phosphorus application and copper concentrations in leaves, and uptake in bulbs plus leaves (Jackson and Yungen, 1980). It was recognized that this type of P-Cu interaction could also occur with sweet corn and low leaf Cu concentrations may be further depressed resulting in a Cu deficiency, which would reduce marketable sweet corn yields. The objective of the sweet corn field studies was to evaluate the extent and importance of the P-Cu interaction. Experiments with rates of P and Cu were established at the North Willamette Experiment Station in 1980, 1981, and Additionally the experiments incorporated the following objectives: 1. Experiment One 1980 i. investigate effects of rates of broadcast P, banded P and broadcast Cu on the P-Cu interaction. ii. determine whether fertilizer B influenced sweet corn yield. 2. Experiment Two 1980 i. investigate P-Cu interaction with rates of banded P and broadcast Cu. ii. investigate influence of lime amendment rate on marketable yields of sweet corn and on P-Cu interaction. ii. determine whether fertilizer B influenced sweet corn yield.

52 38 3. Experiment One 1981 i. investigate influence of broadcast P rate, banded P rate, banded P source and broadcast Cu on sweet corn yields and nutrient concentrations. 4. Experiment Two 1981 i. establish effect of planting date on phosphorus response, lime response and yield and nutrient concentrations 5. Experiment One 1982 i. investigate influence of banded P rate and supplemental Cu on yields and nutrient concentrations of sweet corn. 6. Experiment Two 1982 i. investigate influence of banded P rate and source of banded P on yields and nutrient concentrations of sweet corn leaf samples.

53 39 CHAPTER II MATERIALS AND METHODS Field experiments were established at the North Willamette Experiment Station in 1980, 1981 and Jubilee variety of sweet corn (Zea mays L.) was grown on a Willamette silt loam (Pachic Ultic Argixeroll, fine-silty, mixed, mesic). Plant populations of approximately 86,000 plants/ha were seeded in rows 0.76 m apart for all experiments. No insecticides or fungicides were used. All banded fertilizer treatments were placed 5 cm below and 5 cm to the side of the seed placement. Four replications were used for all experiments. Alachlor and atrazine were applied for weed control at active ingredient rates of 2.8 and 1.1 kg/ha, respectively, approximately 24 hours after seeding and irrigated in for all experiments. Chemical analyses of soil samples from each site are presented in Table II-1. All analyses were by the Oregon State University, Soil Testing Laboratory using the methods described by Berg and Gardner, Planting, sampling and harvest dates are reported in Table 11-2 for all three years of the corn experiments. Ear leaf samples were obtained when the corn was approximately 0.5 to 0.7 m in height by collecting from 10 to 15 partially extended ear leaves. A second ear leaf sample was obtained when the corn was tasselling. The two sampling times will be termed as "early leaf sample" and "tasselling leaf sample". Selected treatments in 1980 and 1981 were sampled to determine total nutrient accumulation. This sample was obtained by collecting 10 or 5 above ground corn plants in 1980 and 1981 respectively, at the same time as the early leaf sample. All plant samples were first dried at 60 C and subsequently pulverized in a Waring blender which had stainless steel blades and carbon bearings. A subsample was ground to pass a 20-mesh sieve in a Wiley mill with all stainless steel parts.

54 40 Table II-1: Soil chemical analyses data for three years of sweet corn experiments on a Willamette silt loam at the North Willamette Experiment Station. Previous Year Exper- Lime Treat- Year iment rate ment ph Pt K Ca Mg Cu Mg/ha cmol/kg limol/kg 1980 one two two two two one one +P one - +Cu one +p +Cu two two two two both both t Conversion factors: cmol P/kg to mg P/kg multiply by 310; cmol Ca or Mg/kg to meg Ca or Mg/100 g multiply by 2; cmol K/kg to meq K/100 g multiply by 1; limol Cu/kg to mg Cu/kg multiply by

55 41 Table 11-2: Planting, sampling and harvest dates for three years of sweet corn experiments. ----Plant Samples Tassel- Experi- Plant- Plant- Early ling Up- --- Harvests -- Year ment ing ing leaf leaf take first second Date 1980 one two one two one two two one two

56 42 The early leaf samples taken in 1980 were ashed in a muffle furnace at 550 C for four hours. The ash was then dissolved in 25 ml of 3M HC1. All other plant samples were wet ashed in a 3 to 1 nitric to perchloric acid mixture. Phosphorus was determined by the molybdate-vanadate colorimetric method (Jackson, 1958). Cations were determined by flame atomic absorption with a Perkin-Elmer 4000 Atomic Absorption spectrophotometer. Boron was determined on the dry ashed samples in 1980 by the azomethine-h method with a sample to buffer to azomethine-h ratio of 2:2:1 (Wolf, 1971). Three qualitative marketable grades were used; number one, fully matured; number two, partially matured; and culls, immature. The weights of number one and number two ears were recorded and the culls were discarded. Cutoff data were obtained by taking a subsample of the number one ears, finding the weight of kernels removed per weight of ears with husks on. This ratio was multiplied by the number one yield to obtain cutoff yield. Analyses of variance were performed on the data collected. Samples collected from borders not receiving phosphorus fertilizer were not included in statistical analyses Sweet Corn Field Studies Nitrogen fertilizer was applied to all treatments at a rate of 160 kg N/ha; 115 kg N/ha broadcast as ammonium sulfate prior to final field preparation plus 45 kg N/ha banded at planting. Experiment One 1980 The site for experiment one was uniformly limed to achieve a soil ph of 6.2. Main plots of copper, boron, and phosphorus in a 2 by 2 by 2 factorial were applied as broadcast treatments to plots measuring 4.6 m by 14.6 m. The main plots were split by 2 rates of banded phosphorus. The rates and carriers were: Cu, 11 kg Cu/ha as copper sulfate pentahydrate; B, 2.0 kg B/ha as Solubor ; P, 33 kg P/ha band or 76 kg P/ha band or broadcast as monocalcium phosphate (0-20-0). All plots had 6 corn rows, one row on either side of the plot did not receive banded phosphorus fertilizer; each pair of the remaining four rows received banded phosphorus treatments. Yield was

57 43 measured from sections of the paired rows. Irrigation and rainfall amounts during the growing season were 31 and 11 cm respectively. Experiment Two 1980 Lime treatments of 0, 4.5, 9 and 13.4 Mg lime/ha were applied in a randomized complete block design in the fall of Each rate of lime was split with broadcast applications of copper and boron in a 2 by 2 factorial. Each of the subplots were split with two rates of banded phosphorus applied to 1.5 m by 14.6 m subsubplots. The rates and sources of fertilizer were the same as used in experiment one Irrigation and rainfall amounts of 34 and 11 cm were received during the growing season. Both of the band treated rows were harvested for 4.6 m for yield determination Sweet Corn Field Studies The 1981 field studies were on the same sites as the corresponding experiment number in Ears were collected from 1.5 by 5.5 m treated plot areas for yield analyses for both 1981 sweet corn experiments. Harvest dates and plant sampling dates are given in Table Experiment One 1981 This experiment involved a 2 by 2 factorial of broadcast applications of phosphorus and copper applied prior to final seed bed preparation. Plot areas that had received broadcast applications of phosphorus or copper in 1980 received the same broadcast applications in 1981 except that the rate of Cu applied in 1981 was 5.5 kg Cu/ha as copper sulfate pentahydrate. The main plots where split by rate of banded P, 33 and 76 kg P/ha, and each rate of banded P was split with 3 P sources. Three P sources were used for the band applications; monocalcium phosphate (0-20-0); TVA urea phosphate ( ); diammonium phosphate ( ), each applied at rates of 33 or 76 kg P/ha (Table 11-3). Ammonium sulfate was applied with monocalcium phosphate bands at a rate of 29 kg N/ha. The nitrogen carrying phosphorus fertilizers banded at 33 or 76 kg P/ha supplied 29 or 68 kg N/ha rates respectively. Ammonium sulfate was broadcast on all plots to achieve a uniform application of 220 kg N/ha for all

58 44 Table 11-3: Treatments for 1981 sweet corn field experiments. Lime Phosphorust Copper Brdct Band Total Experiment ones Mg/ha kg Cu/ha kg P/ha Experiment two Experiment one treatments were used for all three phosphorus sources. Experiment two treatments were used for two planting dates, with each planting having two harvest dates. t All phosphorus broadcast treatments as monocalcium phosphate (MCP) 1 'P band sources; urea phosphate (UP), diammonium phosphate (DAP), and monocalcium phosphate (MCP).

59 45 treatments. The boron variable of 1980 was ignored since it was felt that the small amount of applied B would have dissipated over the previous year. Irrigation and rainfall supplied 29 and 12 cm of water respectively. Experiment Two 1981 The site received a uniform application of 11 kg Cu/ha to mask any residual affects of the 1980 Cu variable. Broadcast phosphorus applications of zero or 76 kg P/ha as monocalcium phosphate were made to plots which had received broadcast phosphorus in Treatments for each of the two planting dates are given in Table A uniform application of 200 kg N/ha as ammonium sulfate was applied, 45 kg N/ha banded with the phosphorus fertilizer and 155 kg N/ha broadcast in early July. The boron variable from the 1980 experiment was again ignored. Irrigation and rainfall supplied 43 cm of water to each planting of which 15 cm and 12 cm was rainfall for planting one and two respectively. Statistical analyses consider each of the harvest dates separately Sweet Corn Field Studies Sweet corn field experiments in 1982 were on a site that had a lime application of zero or Mg lime/ha in a randomized complete block design applied in early Planting, sampling and harvest dates are listed in Table Final harvest areas were 1.5 m by 5.5 m for each plot. Experiment One 1982 Three rates of banded phosphorus were applied plus one treatment with the highest P rate plus a broadcast Cu application (Table 11-5). All plots received a total of 200 kg N/ha, 45 kg N/ha banded at planting plus 155 kg N/ha top dressed as ammonium nitrate applied in early July. Main plots measured 3.0 m by 18.3 m and were split by lime blocks to give subplots of 3.0 m by 9.1 m. The site received 8 cm rainfall and plus 32 cm of irrigation water during the growing season.

60 46 Experiment Two 1982 A split plot experiment was established with zero or 6.7 Mg lime/ha as main plots and five phosphorus sources listed in Table 11-4 as subplots. Treatments applied are listed in Table Ammonium sulfate was broadcast at a rate to give a total of 100 kg N/ha at planting plus ammonium nitrate was applied in early July for a final N total application of 200 kg N/ha. Harvest areas were 1.5 m by 5.5 m. The site received 40 cm of water during the growing season of which 6 cm was rainfall.

61 47 Table 11-4: Phosphorus sources used in 1982 sweet corn field experiment at the North Willamette Experiment Station. (%N-%P-%K) Phosphorus source UPi (urea phosphate, TVA experimental material, non-purified. Produced from commercial grade wet process phosphoric acid added to urea, contains all impurities of the acid. Urea-N, 13.5%; NE1,-N, 2.0%; Total-N, 16.1%; ortho P = total P = 18.4%)j UP (urea phosphate, TVA experimental material, purified by crystalization, 85% removal of impurities) APP (sulfur coated ammmonium polyphosphate) MCP (monocalcium phosphate, TVA electric furnace) DAP (diammonium phosphate) Planted June 2, 1982.

62 48 Table 11-5: Treatments used for 1982 sweet corn field experiment at the North Willamette Experiment Station. --Nitrogent- ----Phosphorus 4 band source From P Lime Copper Band Brdct Source MCP APP UP UPi DAP Mg/ha kg/ha kg N/ha Experiment one kg P/ha _ _ - Experiment two t Nitrogen applied at planting as ammonium sulfate to give 45 or 100 kg N/ha at planting for experiment one or two respectively; both plantings received ammonium nitrate broadcast at 155 or 100 kg N/ha top dressed in early July for a total N rate of 200 kg N/ha. P sources listed in Table 11-4

63 49 CHAPTER II RESULTS Three years of sweet corn field experiments have resulted in an abundance of data. The results to be presented have been limited to those which were part of the original objectives, main treatment effects and interactions of biological importance. In this section when a main treatment affected either concentrations or yield the mean as given, has been averaged over all other main effects. Treatment means for each determination and analysis of variance are presented in the Appendix Sweet Corn Field Studies Experiment One 1980 Plant analyses, yield and analyses of variance summaries are presented in Appendix Tables 1, 2, and 3. Plant Nutrient Analysis. Leaf samples for nutrient analyses were collected at two growth stages during the field season. The early leaf samples were dry ashed to enable determination of concentrations of boron. The tasselling leaf samples were wet ashed in nitric-perchloric acid mixture. The dry ash procedures usually result in lower values for leaf Cu concentration. This may be a result of occlusion of the Cu in silica precipitates which are not soluble in the 3M HC1 which is used to dissolve the dry ash samples. The Cu concentration in tissue samples when using the dry ash procedure are not comparable to Cu concentrations determined by wet ash procedures. Comparisons within dry ashed or wet ashed samples are valid. Experiment one in 1980 was a factorial of broadcast applications of Cu, B, and P, all main treatments split by rate of band placed P. The early leaf sample demonstrated response from added Cu as concentrations increased (significance, P=0.01) from 4.4 to 5.3 mg Cu/kg plant material averaged over all other treatments. Although broadcast P had no influence on early leaf sample P concentration, rate of band placed P did. Banded P increased P concentration from

64 to 0.34 dag P/kg plant material, averaged across all other treatments, when P band rate was increased from 33 to 76 kg P/ha (significance, P=0.001). Zinc concentration in the early leaf sample was decreased from 38 to 34 mg Zn/kg plant material (significance, P=0.05) as a result of the addition of 11 kg Cu/ha. Plant nutrient analysis of tasselling leaf samples showed a significant (P=0.05) influence of broadcast Cu as Cu concentrations increased from 7.5 to 9.2 mg Cu/kg plant material with the addition of 11 kg Cu/ha when averaged over all other treatments. Band placed phosphorus did not influence P concentrations in the tasselling leaf samples whereas broadcast P increased (significance, P=0.05) P concentrations from 0.37 to 0.40 dag P/kg plant material. Copper was significantly influenced by rate of band placed P at this stage of growth as both the rate of banded P (significance, P=0.05) and the interaction between banded P rate and broadcast Cu (significance, P=0.01) reduced Cu concentrations. Rate of band placed P decreased tasselling leaf sample Cu concentration from 8.8 to 7.9 mg Cu/kg plant material. The interaction between P band rate and broadcast Cu on tasselling leaf sample Cu concentrations indicated an antagonistic interaction of P on Cu (Table 11-6). Yield Analysis. Copper and boron applications averaged over all other treatments did not influence marketable yields of sweet corn. Phosphorus fertilization as a broadcast treatment when averaged over all other treatments for harvest one increased the yields of number one ears from 13.8 to 18.4 Mg/ha (significance, P=0.001), decreased number two ears from 9.2 to 7.6 Mg/ha (significance, P=0.05), increased total yield from 23.0 to 26.0 Mg/ha (significance, P=0.01), and increased cutoff yield from 6.0 to 8.0 Mg/ha (significance, P=0.001). Increasing rate of banded P from 33 to 76 kg P/ha, when averaged over all other treatments for harvest one, increased yield of number one ears from 15.0 to 17.4 Mg/ha (significance, P=0.001), increased total yield from 23.3 to 25.3 Mg/ha (significance, P=0.05), and increased cutoff yield from 6.5 to 7.6 Mg/ha (significance, P=0.001).

65 51 Table 11-6: Phosphorus and Cu influence on tasselling leaf sample Cu concentration in sweet corn, experiment one Banded Phosphorus Broadcast Cu (kg Cu/ha) 0 11 kg P/ha mg Cu/kg plant materialt LSD (0.05) 0.9** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over broadcast P and B treatments. (planted 5/7, sampled 8/5) Table 11-7: Broadcast P rate and rate of banded P effects on yield of number one ears, total yield and cutoff yield of sweet corn experiment one, harvest one Phosphorus Broadcast Banded t Yield #1 ears #1 + #2 ears Cutoff from #1 ears kg P/ha Mg/ha LSD (0.05) 1.8*** 1.9*** 0.8*** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over Cu and B treatments. (planted 5/7, harvested 9/4)

66 52 The interaction between broadcast P and rate of banded P for harvest one significantly affected yield of number one ears, number two ears and cutoff from number one ears (Table 11-7). Copper influenced harvest one yields since the interaction between broadcast P, rate of banded P, and broadcast Cu was significant (Table 11-8). However, delaying the harvest by five days for harvest two resulted in more uniform maturity so that yield differences were not significantly affected by any of the treatments. Experiment Two 1980 Plant nutrient concentrations, nutrient uptake analyses, marketable yields, and analyses of variance summaries are presented in Appendix Tables 4 to 9. Plant Nutrient Analyses. Lime treatment did not influence any of the plant nutrient concentrations determined in the early leaf samples, however, in the tasselling leaf sample P, Cu, and Mn were affected by lime rate (significance, P=0.05, 0.01, and 0.001), when averaged over all other treatments (Table 11-9). Broadcast application of Cu increased Cu concentrations in the early leaf sample from 3.7 to 4.2 mg Cu/kg plant material (dry ashed samples, significance, P=0.001). Tasselling leaf sample Cu concentrations were also influenced (significance, P=0.05) by the interaction of lime treatment and broadcast Cu addition (Table II-10). Increasing lime application rate decreased Cu concentrations either with or without Cu addition. Broadcast application of Solubor increased early leaf sample B concentration from 11 to 14 mg B/kg plant material (significance, P=0.001). Rate of banded P influenced early leaf sample P concentration and tasselling leaf sample Cu and Zn. When the rate of banded P was increased from 33 to 76 kg P/ha early leaf sample P concentration increased from 0.31 to 0.35 dag P/kg plant material (significance, P=0.001). This increase in banded rate of P caused a decrease in tasselling leaf sample Cu and Zn concentrations from 8.2 and 38 to 7.5 and 35 mg/kg plant material, respectively (significance, P=0.01, 0.01).

67 53 Table 11-8: Broadcast P rate, broadcast Cu and banded P rate influence on yield of number one ears, total yield and cutoff yield in sweet corn experiment one, harvest one Yields t Phosphorus Cutoff from Broadcast Banded Copper #1 ears #1 +#2 ears #1 ears kg/ha Mg/ha LSD (0.05) 2.5* 2.6** 1.1* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over B treatments. (planted 5/7, harvested 9/4) Table 11-9: Lime effects on nutrient concentrations in tasselling leaf samples of sweet corn, experiment two Tasselling leaf samplet Lime P Cu Mn Mg/ha dag/kg mg/kg LSD (0.05) 0.02* 0.7** 10*** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P, Cu, and B treatments. (planted 5/7, sampled 8/22)

68 54 Table II-10: Lime and Cu fertilization influence on tasselling leaf sample Cu concentration of sweet corn, experiment two Tasselling leaf sample t Lime Copper Rate (kg/ha) 0 11 Mg/ha mg Cu/kg LSD (0.05) 1.4* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P and B treatments. (planted 6/5, sampled 8/22) Table II-11: Lime rate and broadcast Cu effects on total yield and cutoff yield of sweet corn, experiment two harvest one Lime t Yield Cutoff from Copper #142 ears #1 ears Mg/ha kg/ha Mg/ha LSD (0.05) 2.1* NS *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P and B treatments. (planted 6/5, harvested 9/22)

69 55 Nutrient Uptake. Selected treatments were sampled to determine nutrient uptake as influenced by lime treatment, broadcast Cu and rate of banded P at the same growth stage as the early leaf sample. Lime treatments did not influence uptake of P, Cu, Zn, and Mn. Copper uptake was increased from 450 to 510 pg/ten plants (significance, P=0.05) by Cu fertilization. Increasing P band rate from 33 to 76 kg P/ha increased P uptake from 340 to 390 mg/ten plants (significance, P=0.01) and increased Mn uptake from 6.8 to 7.6 mg/ten plants (significance, P=0.05). Yield Analyses. Lime treatment and boron fertilization did not influence yields for either harvest date. Copper depressed harvest two yield of number one ears by 0.5 Mg/ha from 22.8 to 21.7 Mg/ha and cutoff yield by 0.5 Mg/ha from 10.2 to 9.7 Mg/ha (significance, P=0.05, 0.05). Increasing the banded P rate from 33 to 76 kg P/ha increased harvest one yield of number one ears from 16.6 to 17.9 Mg/ha (significance, P=0.05), and cutoff yield from 6.7 to 7.3 Mg/ha (significance, P=0.05). This treatment similarly influenced harvest two yields, increasing (significance, P=0.01) yield of number one ears from 21.6 to 23.0 Mg/ha, increasing (significance, P=0.05) total yield from 24.8 to 26.0 Mg/ha, and increasing (significance, P=0.01) cutoff yield from 9.6 to 10.2 Mg/ha. Interactions between treatments were for the most part not a factor in marketable yields. The interaction between lime treatment and broadcast Cu application influenced total yield (significance, P=0.05) and cutoff yield (significance, P=0.05) of harvest one (Table II-11). Either the 9.0 Mg lime/ha application or 11 kg Cu/ha treatments increased yields as compared to the no lime, no copper yields Sweet Corn Field Studies Experiment One 1981 All plant nutrient, marketable yields and analysis of variance summaries are presented in Appendix Tables 9 and 10. Plant Nutrient Analyses. Broadcast application of P as MCP did not influence plant nutrient concentrations in either sampling.

70 56 A broadcast application of Cu increased (significance, P=0.001) Cu concentration from 6.1 to 8.3 mg Cu/kg plant material in the early leaf sample and from 9.4 to 12 mg Cu/kg plant material in the tasselling leaf sample (significance, P=0.001). Copper addition decreased (significance, P=0.05) tasselling leaf sample P concentration from 0.39 to 0.38 dag P/kg plant material. Rate of banded P influenced early leaf sample concentrations of P, Cu, Mn, and Ca and tasselling leaf sample concentrations of Cu and Mn. Increasing the rate of band applied P from 33 to 76 kg P/ha increased early leaf sample P concentration from 0.42 to 0.43 dag P/kg plant material (significance, P=0.001). This change in P band rate decreased early leaf sample and tasselling leaf sample Cu concentrations from 7.6 to 6.8 and 11 to 10 mg Cu/kg plant material (significance, P=0.01, 0.001). Increased banded P rate also increased early leaf sample Ca concentration from 3.8 to 4.1 dag Ca/kg plant material (significance, P=0.05), and increased Mn concentrations at both sampling dates from 43 to 55 and 86 to 100 mg Mn/kg plant material (significance, P=0.001, 0.001). Source of P in the fertilizer band significantly influenced Mn concentration at both leaf samplings (significance, P=0.001, 0.001) and influenced Zn concentration in the early leaf sample (significance, P=0.05), when averaged over all other treatments (Table 11-12). The interaction between rate of banded P and P source also influenced Mn concentrations in both leaf samplings (significance, P=0.001, 0.01) and Zn concentrations in the early leaf sample (significance, P=0.01), when averaged over all other treatments (Table 11-13). Yield Analyses. Marketable yields were not affected by main treatments, however, interactions between some main factors influenced yields at the 0.05 level of probability. The interaction between broadcast P and rate of banded P was such an interaction affecting number one ears, number two ears and cutoff from number one ears (Table 11-14).

71 57 Table 11-12: Phosphorus source effects on leaf sample Mn and Zn concentrations of sweet corn, experiment one Phosphorus Source Mn Early leaf Zn Samplet Tasselling leaf Mn mg/kg MCP DAP UP LSD (0.05) 3*** 2* 7*** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast, P banded rate, and Cu treatments. (planted 5/27, sampled 7/17 and 8/21) Table 11-13: Phosphorus source and P band rate effects on leaf sample Mn and Zn concentrations of sweet corn, experiment one Sample t Phosphorus Early leaf Tasselling leaf Source Rate Mn Zn Mn kg/ha mg/kg MCP MCP DAP DAP UP UP LSD (0.05) 5*** 3** 10** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over broadcast P and Cu treatments. (planted 5/27, sampled 7/17 and 8/21)

72 58 Table 11-14: Broadcast and banded P effects on yields of sweet corn, experiment one Phosphorus Broadcast Banded #1 ears Yields #2 ears Cutoff from #1 ears --kg/ha-- Mg/ha LSD (0.05) 1.1* 0.3* 0.5* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P source and Cu treatments. (planted 5/27, harvested 9/9) Table 11-15: Lime effects on leaf P concentrations, sweet corn experiment two Sample t Early leaf Tasselling leaf Lime planting 1 planting 2 planting 1 planting 2 Mg/ha dag P/kg LSD (0.05) 0.02** 0.03* NS NS *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast and banded treatments. (planted 5/11, sampled 7/6 and 8/5; planted 6/3, sampled 7/29 and 8/26)

73 59 Experiment Two 1981 All plant nutrient analyses, yield analyses and nutrient uptake data are presented in Appendix Tables 11 to 13 and analyses of variance summaries are presented in Appendix Tables 14 to 16. Plant Nutrient Analyses. Lime treatment influenced concentrations of P (Table 11-15), Cu (Table 11-16), Zn (Table 11-17), Mn (Table 11-18), and Ca (Table 11-19). Leaf concentrations of P and Ca were increased by increasing lime rate whereas the Cu, Zn, and Mn concentrations decreased. Broadcast P increased (significance, P=0.01) tasselling leaf sample P concentration from 0.34 to 0.35 dag P/kg plant material as a result of addition of 76 kg P/ha for sweet corn of planting two. Increasing the rate of banded P from 33 to 76 kg P/ha affected early leaf sample concentrations of; P, from 0.35 to 0.36 dag P/kg plant material (significance, P=0.05); Cu, from 8.4 to 7.6 mg Cu/kg plant material (significance, P=0.001); Zn, from 32 to 29 mg Zn/kg plant material (significance, P=0.05); Mn, from 48 to 50 mg Mn/kg plant material (significance, P=0.01); Ca, from 3.4 to 3.9 dag Ca/kg plant material (significance, P=0.05) for planting one. Tasselling leaf sample Cu concentrations of planting one decreased (significance, P=0.001) from 11 to 10 mg Cu/kg plant material, when averaged over all other treatments as a result of increasing the rate of banded P from 33 to 76 kg P/ha. Phosphorus band rate in planting two increased (significance, P=0.01) early leaf sample concentrations of P, from 0.34 to 0.35 dag P/kg plant material and decreased (significance, P=0.01) Cu concentration from 9.9 to 9.3 mg Cu/kg plant material as a result of increasing the banded P rate from 33 to 76 kg P/ha. The interaction between broadcast P rate and banded P rate modified early leaf sample concentrations of P and Mn in planting two (Table 11-20). Nutrient Uptake. Samples were collected from planting two for nutrient uptake determination at the same growth stage as the early leaf sample. Although the lime rate did not influence the yield of the uptake sample, the lime treatment did increase P concentration and uptake of P but decreased Mn concentration which decreased Mn uptake (Table 11-21). Addition of a broadcast application of 76 kg

74 60 Table 11-16: Lime influence on leaf Cu concentrations, sweet corn experiment two Samplet Early leaf Tasselling leaf Lime planting 1 planting 2 planting 1 planting 2 Mg/ha mg Cu/kg ' LSD (0.05) 1.5* 1.7* 1.4** 1.2** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast and banded treatments. (planted 5/11, sampled 7/6 and 8/5; planted 6/3, sampled 7/29 and 8/26) Table 11-17: Lime effects on leaf Zn concentrations, sweet corn experiment two Samplet Early leaf Tasselling leaf Lime planting 1 planting 2 planting 1 planting 2 Mg/ha mg Zn/kg LSD (0.05) 4*** 7* NS 5** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast and banded treatments. (planted 5/11, sampled 7/6 and 8/5; planted 6/3, sampled 7/29 and 8/26)

75 61 Table 11-18: Lime effects on leaf Mn concentrations, sweet corn experiment two Samplet Early leaf Tasselling leaf Lime planting 1 planting 2 planting 1 planting 2 Mg/ha mg Mn/kg LSD (0.05) 6*** 5*** 14*** 8*** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast and banded treatments. (planted 5/11, sampled 7/6 and 8/5; planted 6/3, sampled 7/29 and 8/26) Table 11-19: Lime effects on leaf Ca concentrations, sweet corn experiment two Sample t Early leaf Tasselling leaf Lime planting 1 planting 2 planting 1 planting 2 Mg/ha dag Ca/kg LSD (0.05) NS NS NS 0.7* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast and banded treatments. (planted 5/11, sampled 7/6 and 8/5; planted 6/3, sampled 7/29 and 8/26)

76 62 Table 11-20: Broadcast and banded phosphorus effects on early leaf sample P and Mn concentrations of sweet corn, experiment two planting two Phosphorus Early leaf samplet Broadcast Banded P Zn ---kg P/ha--- dag P/kg mg Zn/kg LSD (0.05) 0.01* 3* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over lime rate treatments. (planted 6/3, sampled 7/29) Table 11-21: Lime influence on uptake of P and Mn in five sweet corn shoots, experiment two planting two Concentrationst Uptake Lime Yield P Mn P Mn Mg/ha g/5 dag/kg mg/kg ---mg/5 plants- - plants LSD (0.05) NS 0.03* 10*** 60* 1.0** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast and banded treatments. (planted 6/3, sampled 7/30)

77 63 P/ha as MCP increased the yield of the five plant sample from 76 to 92 g, significant at the level of probability. This increase in yield carried over to increased uptake of P (significance, P=0.001), Cu (significance, P=0.001), Zn (significance, P=0.001), and Mn (significance, P=0.01), when averaged over all other treatments, even though there were no increases in concentrations of these nutrients as a result of this treatment. Increasing the rate of banded P from 33 to 76 kg P/ha decreased (significance, P=0.01) Cu concentration from 7.2 to 6.7 mg Cu/kg plant material and decreased (significance, P=0.01) Zn concentration from 44 to 42 mg Zn/kg plant material. This also decreased (significance, P=0.05) uptake of Cu from 600 to 550 pg Cu/five plants and Zn from 3.7 to 3.4 mg/five plants (significance, P=0.05). Yield Analyses. Increasing lime treatment rate for planting one significantly increased the cutoff ratio, weight of kernels on each cob, for both harvests (Table 11-22). Increasing lime treatment rate for planting two harvest one (Table 11-23) and harvest two (Table 11-24) increased the yield of number one ears, decreased yield of number two ears and increased cutoff yield. Broadcast application of 76 kg P/ha increased planting one harvest two yield of number one ears from 23.9 to 25.8 Mg/ha and total yield from 24.6 to 26.3 Mg/ha, both significant at the 0.05 level of probability. This treatment in planting two influenced most aspects of marketable yields (Table 11-25). Increasing the rate of banded P from 33 to 76 kg P/ha in this experiment did not influence harvests yields from either planting. Lime treatment interacted with broadcast P to influence yields for planting two harvest one (Table 11-26) and harvest two (Table 11-27). This interaction resulted in fairly constant total yields as yields of number one ears increased and number two ears decreased when either lime or broadcast P were applied. Lime treatment interacted with rate of banded P to influence total yield of planting one harvest one (Table 11-28).

78 64 Table 11-22: Lime influence on cutoff ratio and cutoff yield for sweet corn experiment two, planting one Harvest One t Harvest Two Cutoff Cutoff from Cutoff Cutoff from Lime Ratio #1 ears Ratio #1 ears Mg/ha Mg/ha Mg/ha LSD (0.05) 0.02* NS 0.01* NS *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast and banded treatments. (planted 5/11, harvested 8/31 and 9/3) Table 11-23: Lime influence on yields of sweet corn, experiment two, planting two, harvest one Yields Lime #1 ears #2 ears #1+#2 ears Cutoff from #1 ears Mg/ha Mg/ha LSD (0.05) 3.1* 1.8* NS 1.5* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast and banded treatments. (planted 6/3, harvested 9/14)

79 65 Table 11-24: Lime influence on yields of sweet corn, experiment two, planting two, harvest two Yields t Lime #1 ears #2 ears #1+#2 ears Cutoff from #1 ears Mg/ha Mg/ha LSD (0.05) 1.9** 1.0* 1.0* 1.0** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast and banded treatments. (planted 6/3, harvested 9/17) Table 11-25: Broadcast P influence on yields of sweet corn, experiment two, planting two Yields t Phosphorus Cutoff from Broadcast #1 ears #2 ears #1+#2 ears #1 ears kg P/ha Mg/ha HARVEST ONE SIGNIF. (P=) NS 0.05 HARVEST TWO SIGNIF. (P=) tall values averaged over lime and P banded treatments. (planted 6/3, harvested 9/14 and 9/17)

80 66 Table 11-26: Lime and broadcast P effects on yields of sweet corn, experiment two, planting two, harvest one Yields t Phosphorus Lime Broadcast #1 ears #2 ears #1+#2 ears Cutoff from #1 ears Mg/ha kg/ha Mg/ha LSD (0.05) 2.0* NS NS 0.9* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P banded treatments. (planted 6/3, harvested 9/14) Table 11-27: Lime and broadcast P effects on yields of sweet corn, experiment two, planting two, harvest two Yields t Phosphorus Lime Broadcast #1 ears #2 ears #1+#2 ears Cutoff from #1 ears Mg/ha kg/ha Mg/ha LSD (0.05) 1.4** 0.9* 1.1* 0.8* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P banded treatments. (planted 6/3, harvested 9/17)

81 67 Table 11-28: Lime and banded P effects on total yield for sweet corn experiment two, planting one, harvest one YieldI Lime Banded Phosphorus Rate (kg P /ha) Mg/ha ---Mg #142 ears/ha LSD (0.05) 1.6* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P broadcast treatments. (planted 5/11, harvested 8/31) Table 11-29: Phosphorus banded and broadcast Cu on nutrient concentrations in sweet corn, experiment one Nutrient Concentrations t P Early leaf sample Tasselling leaf sample Band Copper P K Cu Zn P K Cu Zn kg/ha dag/kg mg/kg dag/kg mg/kg LSD (0.05) 0.04** 0.3** 1.3* 9* NS NS NS 6** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over lime treatments. (planted 5/6, sampled 6/29 and 7/29)

82 Sweet Corn Field Studies Experiment One 1982 All plant nutrient analyses and analyses of variance summaries for that data are presented in Appendix Tables 17 and 18. Yield analyses and analysis of variance summaries for the yield data are presented in Appendix Table 19. Nutrient Analyses. Application of 33 kg P/ha increased early leaf sample P concentration (significance, P=0.01) and decreased Cu concentration (significance, P=0.05), when averaged over all other treatments (Table 11-29). Increasing the rate of banded P to 76 kg P/ha depressed early leaf sample K concentration and tasselling leaf sample Zn concentration both at the 0.01 level of probability (Table 11-29). Lime treatment at a rate of 6.7 Mg lime/ha decreased Zn and Mn concentrations in early leaf samples from 47 to 41 mg Zn/kg plant material and from 72 to 56 mg Mn/kg plant material and in tasselling leaf samples from 45 to 37 mg Zn/kg plant material and from 131 to 102 mg Mn/kg plant material, all significant at the 0.01 probability level. Lime application at a rate of 6.7 Mg/ha increased concentrations of Ca and Mg in tasselling leaf samples from 0.91 and 0.28 to 1.11 and 0.33 dag/kg plant material, respectively, and decreased tasselling leaf sample K concentration from 2.9 to 2.8 dag/kg plant material, all significant at the 0.01 level of probability. Yield Analyses. Marketable yields were not influenced by main treatments of lime or banded P rate or banded P plus broadcast Cu. The interaction between main treatments did result in modifications of yields of number one ears and cutoff from number one ears (Table 11-30). Either application of 33 kg P/ha or 6.7 Mg lime/ha increased yield of number one ears and cutoff yield. There was no additional benefit from either more P banded or the addition of 11 kg Cu/ha after the initial yield increase. Experiment Two 1982 Plant analyses data and marketable yield data are presented in Appendix Tables 20 to 22. The analysis of variance data included in those tables treats the experiment as a completely randomized block

83 69 Table 11-30: Lime, banded P and supplemental Cu addition influence on yield of number one ears and cutoff from number one ears, sweet corn experiment one, #1 ears Yields t Cutoff from #1 ears P Lime (Mg lime/ha) Lime Banded Copper kg P/ha kg Cu/ha Mg #1 ears/ha Mg Cutoff/ha LSD (0.05) P-Cu Treatments 1.6* 1.6* LSD (0.05)lime treatments 1.9* 0.8* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 t(planted 5/6, harvested 8/31) Table 11-31: Lime effect on tasselling leaf sample nutrient concentrations, sweet corn experiment two Tasselling leaf sample t Lime P Ca Mg Cu Zn Mn Mg/ha dag/kg mg/kg SIGNIF. (P=) tall values averaged over P banded and P source treatments. (planted 6/2, sampled 8/17)

84 70 split by blocks of lime. Appendix Table 23 is the analysis of variance data for the experiment treated as a factorial of 2 banded P rates and 4 P sources split by blocks of lime, with the exclusion of the P zero treatment. The results will be presented on the bases of the latter statistical treatment. Plant Nutrient Analyses. Application of 6.7 Mg lime/ha decreased early leaf sample Zn concentration from 49 to 42 mg Zn/kg plant material (significance, P=0.05) and Mn concentration from 78 to 60 mg Mn/kg plant material (significance, P=0.01), when averaged over all phosphorus treatments. This treatment significantly increased P, Ca, and Mg concentrations and decreased Cu, Zn, and Mn concentrations in tasselling leaf samples (Table I1-31). Increasing the rate of banded P significantly increased P concentration and decreased Cu concentration in both leaf samplings (Table I1-32). Source of P in the fertilizer band affected only the concentration of P in the leaf samples (Table I1-33). Yield Analyses. Increasing the lime rate from zero to 6.7 Mg lime/ha increased total yield from 16.3 to 17.5 Mg/ha, significant at the 0.05 level of probability. Increasing the rate of banded P from 33 to 76 kg P/ha increased the yield of number one ears from 6.9 to 10.1 Mg/ha, decreased yield of number two ears from 9.6 to 7.4 Mg/ha and increased cutoff yield from 2.7 to 3.9 Mg/ha all significant at the level of probability. The interaction between lime rate and rate of banded P indicated that at zero lime 76 kg P/ha was required for maximum total yield and minimum proportion of number two ears. Once lime was applied there was no further total yield benefit of a higher rate of banded P than the 33 kg P/ha rate, however, the proportion of number one ears increased by increasing the banded P rate (Table 1I-34). Phosphorus sources banded responded differently dependant on the rate of applied lime. Lime application with UPi actually decreased yields whereas DAP, APP, and UP either resulted in no change with applied lime or increased yields at the lime addition rate of 6.7 Mg lime/ha (Table I1-35).

85 71 Table 11-32: Banded phosphorus effect on P and Cu concentrations in leaf samples of sweet corn experiment two Samplet Phosphorus Early leaf Tasselling leaf Banded P Cu P Cu kg P/ha dag/kg mg/kg dag/kg mg/kg SIGNIF. (P=) NS tall values averaged over P source treatments. (planted 6/2, sampled 7/19 and 8/17) Table 11-33: Influence of banded P source on leaf concentration of P, sweet corn experiment two, Sample t Phosphorus Early leaf Tasselling leaf Source P P dag P/kg DAP UPi APP UP LSD (0.05) 0.02* NS *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over all other treatments. (planted 6/2, sampled 7/19 and 8/17)

86 72 Table 11-34: Lime and banded P effects on yields of sweet corn, experiment two Phosphorus Lime Banded #1 ears Yields t #2 ears #1+#2 ears Mg/ha kg/ha Mg/ha LSD (0.05) NS 1.4* 1.7* *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged over P soucres treatments. (planted 6/2, harvested 9/8) Table 11-35: Lime and source of banded P influence on yields of sweet corn, experiment two, Yields t Phosphorus Cutoff from Lime Source #1 ears #1+#2 ears #1 ears Cutoff ratio Mg/ha Mg/ha 0 DAP UPi APP UP DAP UPi APP UP LSD (0.05) 2.0** 2.5* 0.8** 0.02*** *,**,*** Represent F-test Significance P=0.05,0.01,0.001 tall values averaged P rate treatments. (planted 6/2, harvested 9/8)

87 73 CHAPTER II DISCUSSION A limited number of samples were collected from 1980 and 1981 field studies from selected border rows of some of the treatments which had not received banded P. This was done to have some record of sweet corn nutrient concentrations and marketable yields with no banded P, but with rates of broadcast P and/or lime amendments. Due to the design of the experiments this data is not appropriate for statistical comparison with the experimental treatments. This data is presented in Appendix Tables 24 to 26. The addition of banded P and increased rate of banded P usually depressed leaf Cu concentrations, this was greater in the early leaf samples but was also present in the tasselling leaf samples. Copper concentration was decreased to 3.8 mg Cu/kg plant material in the early leaf sample of experiment one 1982 as a result of the addition of 33 kg P/ha, compared to 5.4 mg Cu/kg plant material in the zero P treatment demonstrates this effect of banded P. In that experiment increasing the rate of banded P or adding 11 kg Cu/ha did not further influence the Cu concentration in the early leaf sample. Increasing the rate of banded P from 33 to 76 kg/ha decreased leaf Cu concentrations in most of the experiments. Copper concentration in tasselling leaf samples of experiment one 1980 decreased from 8.8 to 7.9 mg Cu/kg plant material and in experiment two 1980 from 8.2 to 7.5 mg Cu/kg plant material as the rate of banded P was increased from 33 to 76 kg P/ha. Similar changes occurred in the 1981 leaf sample as a result of increased banded P rate. Increasing banded P rate from 33 to 76 kg P/ha decreased total uptake of Cu in a whole plant sample from 600 to 550 pg Cu/5 plants in experiment two, planting two The interaction between banded P rate and leaf Cu concentrations has been clearly demonstrated in this series of sweet corn experiments. Interaction between broadcast P and leaf Cu

88 74 concentrations was not evident. The interaction between banded P and leaf sample Cu did not influence yields in these experiments. The decrease in Cu concentration in leaf samples may have had its origin in the reactions within the fertilizer band. The soil solution concentration of Cu in a Willamette CL from the sweet corn study site was depressed by the addition of phosphorus, and rate of addition of phosphorus as MCP in a laboratory incubation study (Chapter I of this thesis). That result on soil solution Cu concentration was in the presence of added Cu in the fertilizer band with the MCP and AmS. This would indicate that the decrease in leaf Cu concentrations may be a result of decreased Cu concentrations in the soil solution in the fertilizer band with added P. The DTPA extractable soil Cu for the sweet corn experimental site in all three years was greater than 8.3 pmol/kg soil (0.53 pg/g) which is in excess of Lindsay and Norvell's (1978) suggested soil critical level of 3.2 pmol/kg soil (0.2 pg/g). Sweet corn grown on a soil with a lower level of soil Cu may have become Cu deficient under the conditions of this series of experiments if banded P depressed Cu uptake as it did in some these experiments. Recent literature the P-Zn interaction indicates that the P-Zn interaction is a result of a physiological change within the plant cells as a result of deficiency of Zn (Welch, et al., 1982). Zinc deficiency can also occur as a result of liming or addition of high rates of phosphorus (Adams, J., 1982; Liebhardt, 1979). The information gathered in the soil solution studies (Chapter I of this thesis) and the sweet corn field studies suggest that the interaction between P and Cu is in the soil, not in the plant. This conclusion is strengthened by the observation that the antagonism between P and Cu occurred in these studies as a result of banded P but not broadcast P. The interaction between P and Zn does not appear to be sensitive to placement of phosphorus. The placement of P should be of little consequence if the depression of Cu concentration in sweet corn was physiological in nature. The Cu concentrations in sweet corn leaves, although they were not excessive would be consider sufficient for normal growth. Zinc concentrations are usually low to

89 75 deficient in plants which suffer from Zn deficiency induced P toxicity (Jackson and Carter, 1976). Copper fertilization at a rate of 11 kg Cu/ha as a broadcast application of copper sulfate pentahydrate effectively increased Cu concentrations in leaf samples in this series of experiments. The Cu applications did not influence yields. It would therefore be assumed that Cu concentrations in sweet corn leaves in these experiments were adequate for normal growth. Copper concentrations in these experiments ranged from 3.0 to 11 mg Cu/kg plant material for the early leaf sample and from 6.0 to 14 mg Cu/kg plant material for the tasselling leaf sample. The experiments with rates of added lime indicated that for the site used, application of 4.5 Mg lime/ha, which increased soil ph from 5.5 to 5.9 in 1980 and 5.6 to 6.0 in 1981, was sufficient for maximum production of sweet corn. Although application of higher rates of lime altered some plant nutrient concentrations, yields were usually not increased. Hemphill and Jackson (1982) on this same experimental site obtained similar results with bush beans and carrots as a result of increased lime application rate. Kamprath suggested that liming to a soil ph of 5.8 to 6.2 was adequate if all nutrients were in adequate supply (McLean and Kamprath, 1970). The results of this series of experiments demonstrate that a soil ph of 5.8 to 6.0 should be adequate for sweet corn production. Application of phosphorus in bands, and increased rate of banded P usually increased sweet corn yields, P concentrations, and altered concentrations of other nutrient in some of the experiments. Band placement has usually been found to be superior to broadcast P applications at supplementing soil phosphorus. Peterson et al. (1981) suggested that this superiority of banded P varied from 1:1 to 3:1 dependant on conditions and the level of soil P. Band placement is particularly advantageous where the soil is cold and wet during the growing season (Sutton, 1969). That would be the condition of the sweet corn experimental site for the planting in early May. Sheppard and Racz (1982) presented information on the effect of soil temperature on wheat utilization of applied P. As soil temperature

90 76 increased root proliferation in a fertilizer band decreased and signs of P toxicity to roots were evident at a soil temperature of 25 C. The sweet corn plantings at early dates usually indicated an advantage of banded P compared to broadcast P. Experiment two, planting two of 1981 did not show this banded P advantage. In that experiment broadcast P application was far superior to banded P at increasing yields. That experiment may have demonstrated the adverse type of reaction from banded P that Sheppard and Racz (1982) reported for wheat. The soil temperature for sweet corn experiment two, planting two 1981 would not be expected to be cold. During the period from June 3, 1981, when the corn was planted, to June 15, 1981, the soil temperature at the North Willamette Experiment Station at depths of 5 cm and 20 cm reached average maximum temperatures of 20 and 18 C and average minimum temperatures of 13 and 17 C, respectively (North Willamette Experiment Station records). Whereas the soil temperature from May 11, 1981, the date of the early planting to May 23, 1981, the soil temperature were a maximum of 20 and 17 C and a minimum of 12 and 15 C at 5 and 20 cm, respectively. Therefore it is possible that the band placement at that late of planting date may not be as effective for the conditions of the experimental site as a broadcast application of P. It must be noted however that all measurement of broadcast P were made in the presence of banded P at rates of 33 or 76 kg P/ha. Three phosphorus sources for experiment one 1981, MCP, UP, and DAP, were all being equally effective in increasing yield. Plant nutrient concentrations were affected by the P banded source. Urea phosphate and diammonium phosphate both resulted in elevated leaf sample Mn concentrations as compared to monocalcium phosphate banded with ammonium sulfate. The soil ph of experiment one 1981 was approximately 6.3. The increase in plant Mn concentration was not detrimental at this soil ph level. Comparisons were made in experiment two 1982 between band placement of the four sources DAP, UPi, APP, and UP. Sweet corn leaf sample P concentrations were affected differently by the source of P in the fertilizer band. The TVA experimental products UPi and UP re-

91 77 suited in lower leaf P concentrations than either DAP or APP. The four sources also resulted in differing yield responses with amendment of soil ph by lime. The two grades of the TVA experimental urea phosphate responded in opposite trends in yield as a result of the addition of 6.7 Mg lime/ha which altered soil ph from 5.4 to 6.0. Use of the impure product UPi at low soil ph resulted in the highest yield. The yield at higher soil ph with this product was depressed and resulted in the lowest total yield at the higher soil ph level. The opposite trends in yield responses occurred with the pure UP product. Recent analyses by F. E. Knasawneh (Research Soil Scientist, Agricultural Research Branch, Division of Agricultural Development, Tennesse Valley Authority, Muscle Shoals, Alabama) has shown that there is significant concentration of biurete in the UPi material; which is toxic to germinating seedlings and would delay plant development. Planting dates can not be compared statistically in this series of experiments since true randomization of planting dates was not feasible. Some general observations can be made as to the effect of planting date. Yields of experiments planted in early May were higher than plantings in late May to early June. Planting dates in early June or late May tended to respond to a lesser extent to banded P rate and may have benefited more from a broadcast application of P. Lime treatments may have been a more important factor in attaining maximum yields of late planted sweet corn. Both in experiment one and experiment two of 1980 boron fertilization increased early leaf sample B concentrations. The boron had been applied at a rate of 2 kg B/ha as Solubors. It can be concluded that this treatment can effectively increase sweet corn boron concentrations. Boron treatments did not result in yield increases. Boron concentrations in the absence of added B were 7 to 9 mg B/kg plant material. This level of B in early leaf samples can be assumed to be sufficient for normal growth of sweet corn.

92 78 CHAPTER III Onion Field Studies on Organic Soils INTRODUCTION Onion field studies conducted on a mineral soil at the Southern Oregon Experiment Station (SOES) in 1978 and 1979 with rates of banded and broadcast phosphorus with and without additional Cu indicated an antagonistic influence of phosphorus on Cu concentration and uptake by onions was occurring (Jackson and Yungen, 1980). The onion study at the Southern Oregon Experiment Station had been conducted on a mineral soil low in phosphorus. Commercial onion production in Western Oregon is predominately in areas of high organic matter soils which have high residual P levels from past fertilizer applications. The studies in southern Oregon may not be applicable to these organic soils but that location offered an opportunity to evaluate P-Cu interactions on a soil with a marked P response. Studies were initiated on organic soils of Lake Labish to ascertain whether the same P-Cu interaction could also be expected to occur when organic matter and soil analyses for available P were high. The major objective of the onion field studies was to obtain information on the possible interaction between P and Cu using organic soils. Additionally the following objectives were incorporated into the experiments. 1. Kurth and Klampe sites 1980 i. investigate rate and placement of P influence on onion yields and nutrient concentrations in onion leaves. ii. investigate source, rate and placement of fertilizer Cu. iii. investigate the effect of two soils on the above treatments. 2. Kurth and Klampe sites 1981 i. investigate rate and placement of P and Cu fertilizers

93 79 on onion yields and nutrient concentrations in leaves. ii. investigate rate and source of Cu fertilizer for onions on organic soils. iii. investigate nitrogen rate and placement, and manganese fertilization effects on onions at Klampe site only Field Study at Klampe site i. investigate copper, zinc, manganese and nitrogen fertilizer effects on onions.

94 80 CHAPTER III MATERIALS AND METHODS Danvers variety of onions (Alluim sp.) were seeded at two sites in 1980 and 1981 and at one site in The soils used at the two sites are described in Table III-1. Leaf samples were collected for chemical analyses once in 1980 and twice in 1981 and The leaf sampled was the third visible leaf collected from 10 to 20 plants at each sampling. The onion bulbs were 2 to 4 cm in diameter at the first sampling and were 4 to 6 cm in diameter at the second sampling, approximately 4 to 6 weeks later. Samples were prepared and analyzed by the same procedures as described for sweet corn in Chapter Two of this thesis. Marketable grades of onions were determined by size. Four grades were used, less than 4.5 cm, 4.5 to 7.6 cm, greater than 7.6 cm and culls. The culls were discarded, the weights of the three marketable grades were recorded. Pesticide and irrigation applications were made by the producers and were in accord with normal practices for onion production in the Willamette Valley of western Oregon. Fertilizer additions common to each year were made at both sites by the producers in addition to the experimental treatments. The Kurth site had a preplant application of 140 kg K/ha as potassium chloride plus 26 kg K/ha 17 kg Mg/ha and 34 kg S/ha as SUL- PO -MAG (K SO *2MgS0 ) The Klampe site had a top dress application of 13 kg N/ha and 22 kg Ca/ha as calcium nitrate (Ca(NO3 ) ) applied in early July of each year. 2 Surface applications of fertilizer were used at both locations incorporated by harrowing and field leveling. This procedure mixed the fertilizer material with the surface 5 to 10 cm of soil. Band application in all cases were made by banding the fertilizer material 4 to 5 cm directly below the seed placement. The seeding in 1980 was done with Planet Junior vegetable planters at both locations. Seeding in 1981 consisted of first banding the fertilizer material at a depth of 5 to 7 cm below the soil surface followed by the producer

95 81 Table III-1: Soil characteristics and dates of seeding and sampling for three years of onion experiments. Site Series Name Classification Kurth Semiahmoo Typic Medisapist, euic, mesic Klampe Labish Cumulic Humaquepts, silty clay loam, fine montmorillonitic, mesic, acid Dates of seeding and leaf sampling Site Year Seeding date First sample Second sample Uptake sample Kurth Kurth Klampe Klampe Klampe Soil analyses t Site Year ph P K Ca Mg Cu Zn Mn OM cmol/kg ---pmol/kg--- dag/kg Kurth Kurth Klampe Klampe Klampe t Conversion factors: cmol P/kg to mg P/kg multiply by 310; cmol Ca or Mg/kg to meq Ca or Mg/100 g multiply by 2; cmol K/kg to meq K/100 g multiply by 1; pmol Cu, Mn or Zn/kg to mg Cu Mn or Zn/kg multiply by , or respectively; dag/kg to % multiply by 1.

96 82 seeding directly over the fertilizer band, this procedure was used to improve the stand establishment. The 1982 experiment was seeded by the producer, no fertilizer band treatments were included. The seeding rate of Danvers variety of onions was from 2.8 to 3.4 kg seed/ha in all experiments. Analysis of variance was performed on all data collected Onion Field Studies The treatments listed in Table were established in a randomized complete block design with four replications at both experimental sites. Kurth Site 1980 Ammonium sulfate was applied as a broadcast treatment at a rate of 25 kg N/ha at seeding to the entire experimental site. The site was not harvested for final yield due to poor stand establishment. Leaf and uptake samples were obtained on the dates reported in Table Klampe Site 1980 The experimental site received preplant applications of ammonium sulfate at a rate of 45 kg N/ha and potassium chloride at a rate of 83 kg K/ha. Harvest yield and plant samples were obtained at this site on the dates recorded in Table III-1. Yields of marketable onions were obtained by harvesting all plants in 5.5 m of each of the four treated rows of each plot Onion Field Studies The treatments listed in Table were established in a 4 by 2 phosphorus band rate by banded copper factorial, split by blocks of broadcast phosphorus. Smaller experiments were established at each site in randomized complete block designs as described in Table Statistical analyses of the small experiments was separate from the main experiment. Kurth Site 1981 A common treatment of 25 kg N/ha banded below the seed was applied as ammonium sulfate. Seeding and sampling dates are listed

97 83 Table 111-2: Fertilizer treatments used for both 1980 onion field experiments. Treatment t number --Phosphorus-- Brdct Band Rate Copper Placement Source ---kg P/ha-- kg Cu/ha Brdct CuSul Brdct CuSul Brdct CuSul Brdct CuSul Brdct CuSul Brdct CuSul Brdct CuSul Brdct CuSul Brdct CuSul Brdct CuSul Brdct CuSul Band CuSul Brdct CuEDTA Band CuEDTA Brdct CuEDTA Band CuEDTA Brdct CuEDTA Foliar CuEDTA Band CuEDTA Foliar CuEDTA t Phosphorus supplied as monocalcium phosphate; CuSul represents copper sulfate pentahydrate; CuEDTA represent disodium copper ethylenediaminetetraacetate.

98 84 Table 111-3: Fertilizer treatments used for both 1981 onion field experiments. Coppert Manganese Phosphorus Place- ----Nitrogen-- Place- Brdct Band Rate 4 Source ment Band Brdct Rate Source ment Treatments at both Kurth and Klampe sites ----Treatments at the Klampe site only -kg P/ha- kg Cu/ha kg/ha kg/ha kg/ha MnSul Band MnSul Band MnSul Band MnSul Band CuEDTA Band MnSul Band CuEDTA Band MnSul Band CuEDTA Band MnSul Band CuEDTA Band MnSul Band MnSul Band MnSul Band MnSul Band MnSul Band CuEDTA Band MnSul Band CuEDTA Band MnSul Band CuEDTA Band MnSul Band CuEDTA Band MnSul Band Klampe site additional treatments CuEDTA Band CuEDTA Band MnSul Band CuEDTA Band MnSul Band CuEDTA Band CuEDTA Band MnSul Band CuSul Band MnSul Band CuSul Band MnSul Band Kurth site additional treatments CuEDTA Band CuSul Band CuSul Band tphosphorus supplied as monocalcium phosphate; nitrogen supplied as ammonium sulfate; CuSul = CuSO4.5H20; CuEDTA = disodium copper ethylenediaminetetraacetate; MnSul = MnSO Foliar copper was applied to all plus copper treatments at Kurth site at a rate of 0.5 kg Cu/ha as CuEDTA to give a total rate of 3.0 kg Cu/ha.

99 85 in Table Marketable yields were obtained by collecting 4.9 m of three of the four treated rows. Klampe Site 1981 All treatments except those indicated in Table received 50 kg N/ha, 25 kg N/ha broadcast and 25 kg N/ha banded, as ammonium sulfate, 5 kg Mn/ha banded as manganese sulfate and 83 kg K/ha as potassium chloride broadcast prior to final seedbed preparation. Seeding and sampling dates are listed in Table III-1. The four rows receiving the experimental treatments were harvested for a length of 4.9 m each to determine marketable yields Onion Field Study Only the Klampe site was used in Copper, zinc and nitrogen treatments listed in Table were all broadcast prior to final seedbed preparation to plots 5.2 m by 12.2 m with foliar manganese treatment applied to half of each plot and a split application of nitrogen applied to most plots in July. The foliar Mn treatment was applied as a spray of manganese sulfate on 6-2, 6-26, 7-2 and All treatments received a preplant application of 44 kg P/ha as monocalcium phosphate and 83 kg K/ha as potassium sulfate. Leaf samples were collected on the dates listed in Table Marketable yields were determined by harvesting 9.1 m lengths of four rows in the treated areas.

100 86 Table 111-4: Fertilizer treatments used for the 1982 Klampe onion field experiment. Manganese t Copper Zinc Nitrogen at Planting Top Dress Source kg Mn/ha kg Cu/ha kg Zn/kg ----kg N/ha Urea Urea Urea Urea Urea AmC Urea Urea Urea Urea Urea AmC1 t Manganese supplied as a foliar application of manganese sulfate; copper and zinc supplied as broadcast treatments of CuS0 '5H 0 2 or ZnS0 '1,1 O. nitrogen as urea or ammonium chloride (AmCi); ' phosphorus 2 and potassium applied to the entire site at rates of 44 and 83 kg/ha respectively as monocalcium phosphate or potassium sulfate.

101 87 CHAPTER III RESULTS AND DISCUSSION The data for treatment means and analysis of variance of each experiment from three years of onion field studies are presented in Appendix Tables 27 to 40. The experimental treatments had in most cases, no influence on any aspect of onion production. The reasons for this outcome are not completely known. Stand establishment was a major problem in the experiments and may be largely responsible for the lack of yield responses. This may have been a result of poor germination, depth of seed placement, seed not dispensed uniformly by the planters, infestation by insects, diseases or just bad luck. Excessive water in one experiment standing over the Kurth experimental site reduced the stand of onions. Stand establishment should have had little influence on plant nutrient concentrations. The lack of statistical significance in most of the nutrient concentrations which were determined and the inability to prove that applied fertilizers were being utilized by the onions would suggest that the added fertilizer was not necessary. The extremely low levels of leaf Zn and Mn would indicate that these nutrients may be limiting growth. A band application of manganese sulfate and/or ammonium sulfate increased leaf Mn concentrations from 15 to 25 mg Mn/ kg plant material at the Klampe site in 1981, but these treatments did not result in yield increases. Application of Zn and Mn fertilizers were made in the 1982 field study at this site. These treatments did not result in plant nutrient concentration increases nor did they result in yield increases. The original objective of these onion experiments on organic soils was to study the interaction between P and Cu. This interaction was not found in onions at either study site. Incubations with soils from these sites with banded MCP and CSPH resulted in either no change in Cu at increasing rate of banded P or

102 88 increase in soil solution Cu concentration (Chapter I of this thesis). Thus it may be assumed that the interaction between P and Cu may be limited to soils which are dominated by inorganic colloids. Since neither leaf Cu concentrations nor yields were influenced by Cu fertilization no statement can be made as to Cu source, rate, placement or leaf concentrations. This also applies to the P rate and placement. Means of nutrient concentrations and yields for each of the experiments are presented in Table Although yields are quite good, concentrations of Cu, Zn, and Mn in leaf samples are below optimum levels reported in the literature. Since applications of these nutrients did not influence nutrient concentrations or yields it is felt that either the levels reported are adequate, or some unknown factor is limiting utilization of these nutrients.

103 89 Table 111-5: Average nutrient concentrations and yields of onion field studies. YEAR EXPERIMENT NUMBER ONE TWO ONE TWO 1982 ONE LEAF SAMPLE ONE P (dag/kg) Cu (mg/kg) Zn (mg/kg) Mn (mg/kg) LEAF SAMPLE TWO P (dag/kg) Cu (mg/kg) Zn (mg/kg) Mn (mg/kg) YIELDS TOTAL (Mg/ha) MEDIUM (Mg/ha) LARGE (Mg/ha) SMALL (Mg/ha) tall values averaged over all treatments.

104 90 SUMMARY Field experiments with sweet corn and onions were established in 1980, 1981, and 1982 to study mineral nutrition as influenced by fertilizer materials and lime amendments. The sweet corn experiments were all at the North Willamette Experiment Station on a Willamette SiL. The experimental sites had uniform lime application to achieve an optimum soil ph or rates of lime were established in the fall of The onion studies were on two organic soils, Semiahmoo and Labish, on the Lake Labish organic soil deposit in the Willamette Valley which is used predominately for commercial onion production. Incubation studies were also conducted with soil samples from each of the study sites as well as five other locations in western Oregon. A major objective for these studies was to investigate the possible interaction between fertilizer phosphorus and native or applied Cu. The soil incubation studies identified two types of effects of band placed MCP on soil solution Cu concentration in the presence of added Cu. In five mineral of five soils MCP added in a band decreased soil solution Cu concentrations by as much as 8 fold. In three organic soils, which included one mineral soil with low clay content and relatively high organic matter content, banded MCP either did not influence soil solution Cu concentrations or increased soil solution Cu concentration. The sweet corn experiments confirmed that an antagonistic interaction was occurring between band applied P and Cu. This antagonism did not occur with broadcast applications of phosphorus and was not altered by Cu fertilization or lime amendment. The field studies with onions on organic soils did not demonstrate this interaction between P and Cu. Since the P-Cu interaction occurred in sweet corn only with the banded P applications, it is possible that P placement may be a factor in the P-Cu interaction. The studies with the mineral group of soils in incubations with MCP and Cu lead to the conclusion that the interaction between banded P and Cu may be a result of banded P itself. The lack of a P-Cu interaction between in the onion experiments on organic soils which did not demonstrate the

105 91 antagonism between banded P and Cu in incubation studies strengthens this conclusion. Therefore the interaction between P and Cu probably occurs in the soil, not in the plant and may be limited to soils which have dominately mineral soil colloids. The studies on sweet corn production usually indicated an advantage of banded P as the method to increase plant utilization of applied P. In one experiment with a planting date in early June broadcast P as MCP was more effective than banded P. This may have been due to warm soil temperatures at that planting date compared to earlier plantings. Source of banded phosphorus, did not affect response from added P, with the exception of two TVA experimental materials. The two TVA experimental urea phosphate products need further field testing to ensure that detrimental effects are not common to these products. The opposite yield response to the two forms of the urea phosphate at two levels of soil ph also indicate the need of further study of these materials. Sweet corn experiments with rates of lime amendments indicated that soil ph in the range of 5.8 to 6.0 was adequate for sweet corn production. Some nutrient concentrations were altered by higher soil ph levels but this generally did not result in a yield increase compared to soil ph in the range of 5.8 to 6.0. Copper sulfate broadcast at a rate of 11 kg Cu/ha was found to be an effective treatment for increasing sweet corn leaf Cu concentrations. Yield increases as a result of this Cu fertilization did not occur. It was assumed that sweet corn Cu levels determined in these studies, from 3.0 to 11 mg Cu/kg for the early leaf sample and 6.0 to 14 for the tasselling leaf sample, were adequate for normal growth. Application of 2.0 kg B/ha as Solubor increased early leaf sample B concentrations from 7-9 to mg B/kg plant material. This treatment did not influence yields, therefore this level of B in early leaf samples of sweet corn is assumed to be adequate for normal growth. Delaying planting from early May to early June resulted in decreased maximum yields. Experiments with onions at two sites on Lake Labish did not respond to most of the fertilizer treatments. Band applications of

106 92 either manganese sulfate or ammonium sulfate were effective treatments for increasing leaf Mn concentrations at the Klampe site in In one of the experiments band applications of MCP increased leaf P concentrations. These treatments did not affect yields or alter proportion of the marketable sizes of onions. Further and more comprehensive monitoring of nutrient levels is required to clarify reasons for the lack of response by onions to added nutrients. Soil solution extraction by the centrifugation procedure has proven to be a very useful tool for assessing effects of fertilizer practices. This technique can be used on very small samples. Studies with this technique may be useful in obtaining a more thorough understanding of the influence of fertilizer practices on plant responses.

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112 APPENDIX