TSADILAS Christos, SAMARAS Vasilios, SIMONIS Asterios, SETATOU Helen

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1 Scientific registration n o : 776 Symposium n o : 6 Presentation : poster Changes in DTPA-extractable iron, zinc, manganese and copper after liming Modification de la teneur du sol en fer, zinc, manganèse, cuivre extractibles par le DTPA après chaulage TSADILAS Christos, SAMARAS Vasilios, SIMONIS Asterios, SETATOU Helen National Agricultural Research Foundation - Institute of Soil Classification and Mapping, Theofrastou street, 5 Larissa, Greece. tsadilas@lar.forthnet.gr Abstract A three years (995, 996, 997) field experiment was conducted in a strongly acid Ultic Haploxeralf, in Central Greece, in order to study the change of the available forms of Fe, Zn, Mn, and Cu after soil liming. The liming materials used were refuse lime of a sugar beet factory and burned lime. The results showed that soil ph increased from.8 in the control treatment to 6.9 during the first year. was remained unchanged during the second year while it was lowered in the third year of experimentation. DTPA extractable metals showed the following trends: Mn 95 >Mn 96 >Mn 97, Fe 95 >Fe 96 <Fe 97 =Fe 95, Zn 95 =Zn 97, and Cu 95 >Cu 96 >Cu 97. Negative strong relationships were observed between soil ph and Fe and Mn. Zinc was also negatively correlated with soil ph but weaker, while Cu was not significantly correlated with soil ph. DTPA test was found efficient only for Mn. Addition of up to 5 ton ha - refuse lime and 6.5 ton ha - burned lime keep soil ph to the desirable level for at least three years, while rates of ton ha - refuse lime above three years. Introduction Extensive areas in Greece, especially in the western part, are covered by soils with acid surface horizons. This acidity is mainly due to the continuos use of nitrogen containing fertilisers and especially ammonia based fertilisers. Productivity of these soils is very low and for its improvement liming is used. Liming materials used in Greece are usually limestone, burned lime and refuses of sugar factories. Liming of soils has some consequences related to soil ph change. The most common of them is the change of the availability of metals. For example Schwab et al. (99) reported that soil ph decrease due to continuos use of ammonia fertilisers resulted in a significant increase of DTPA extractable iron (Fe) and manganese (Mn). Zinc (Zn) on the other hand was increased with soil ph while copper (Cu) was unaffected. Although there is some experience in Greece on the effect of liming on the improvement of acid soils productivity (Tsadilas et al., 997), there are no sufficient data on the effect of liming on the availability of metals (Tsadilas, 997) and the duration of the beneficial effect of the liming. So, the purpose of

2 this study was to investigate the ph variation after liming and the subsequent changes of the available forms of Fe, Zn, Mn, and Cu as they are estimated by the DTPA method (Lindasy and Norvell, 978). Materials and Methods A three year field experiment with wheat (Triticul vulgare, var. mexicali) was conducted in the Elassona area, which is located in the West Thessaly, central Greece. The soil was a strongly acid Ultic Haploxeralf, which dominates in the area studied. The basic soil physicochemical characteristics are presented in Table. The experimental design was completely randomised blocks, with seven treatments which were replicated four times. The treatments were: control (C), without liming, three treatments included addition of 7.5, 5, and ton ha - of refuse sugar beet lime (RL, RL, and RL respectively) and three treatments included addition of.5,.5, and 6.5 ton ha - burned lime (BL BL and BL respectively). The experimental plots were x m with a band of cm between them. The liming materials were applied at the beginning of October of the first year of experimentation (995) and immediately after the application they were incorporated to the soil in a depth of about 5 cm. The soil was fertilised with kg ammonium sulfate, which was applied basically before the sowing, and 5 kg ammonium nitrate applied in the early of the followed spring. The sowing was carried out at the beginning of November. Harvesting was done in the next June. The experiment was identically repeated in the same place for the two consequent years 996 and 997. At the boot stage in all the three years of experimentation, composite surface soil samples were collected from each plot and after the suitable preparation (air drying, crushing and messed through a mm sieve) were analysed for ph in water (:) (McLean, 98), and for Fe, Zn, Mn, and Cu using the DTPA procedure of Lindasy and Norvell (978). In addition, at the same time, plant samples were collected by each plot and analysed (Mills and Jones, 996) for the same metals. Metals in all the extractants were determined with atomic absorption. Results and Discussion The soil used was a strongly acid, well drained, light textured, with low organic matter content and low cation exchange capacity (Table ). Table. Selected properties of the soil studied ph (water :).8 clay content, g kg - 5 organic matter, g kg - 5 cation exchange capacity, cmol(+) kg exchangeable Al, mg kg - 75 Soil liming increased soil ph from.8 to 6. and 6.9 with the highest amount of refuse sugar beet lime and burned lime respectively (Table ). These ph values were remained unchanged during the first year, from 995 to 996. Comparison of the respective values in pairs using the t-test (Hoshmand, 99) gave a t value of.6 which

3 Table. variation during the three years of experimentation C.8a*.a.7a BL 5.ab 5.55bc.68ab BL 6.bc 5.ab 5.abc BL 6.bc 6.cd 5.9abc RL 5.99bc 5.7bc 5.abc RL 6.5bc 6.6cd 5.9bc RL 6.9c 7.d 6.9c * Numbers in the same column followed by different letters differ significantly at the probability level P<.5 according to the Tuckey s multiple range test was not statistically significant. However, after the second year in 997, soil ph begun to raise. The respective t value of the t-test in the comparison of ph values in 996 and 997 was.5, significant at the P<. probability level. target of 6.5 was approached in the first year with addition of 5 ton ha - sugarbeet refuse lime and addition of 6.5 ton ha - burned lime. In the second year, soil ph dropped below 6.5 in both cases of liming materials. Considering the ph value of around 5.5 as the lowest desirable value, from the data of Table, it is resulted that liming with 5 ton ha - sugarbeet refuse lime or with 6.5 ton ha - burned lime soil ph can be kept in the desirable level for at least three years, while rates ton ha - of refuse sugarbeet lime keep the ph in the desirable level more than three years. The trend of the metals studied during the three years of experimentation is shown in Figure. Extractable manganese was not significantly affected in all the treatments in the first year, after the application of the liming materials. However, in the subsequent years 996 and 997 it was significantly decreased, although its variability was found high. Comparing the extractable Mn values in pairs using the t-test, it was found to follow the order Mn 995 >Mn 996 >Mn 997. Strong negative relationships between soil ph and extractable Mn was found for the years 996 and 997. The respective correlation coefficients were r=-.8*** (Figure ) and r=-.76***. This correlation was weaker for the first year 995 (r=-.*). Similar results were reported by several workers (Follet and Lindsay, 97). Soil liming caused a statistically decrease in the Mn concentration in wheat dry matter. From 9 mg kg - dry matter it was reduced up to 8 mg kg - in the treatment A and in mg kg - in the treatment B. This was not true for the other metals studied (Table ). A significant correlation was found between soil extractable Mn and Mn in the wheat tissue (r=.6***). This indicates that DTPA soil test is in some degree suitable for measuring available soil Mn. In contrast, the DTPA test was found not efficient for the other metals studied for which the correlation coefficients between their concentration in the soil and in the dry matter were not significant. Table. Influence of soil liming on the metal concentration in wheat dry matter

4 Mn Zn Cu Fe mg kg - dry matter C 9b 5.a 7.a.a BL 7a 5.5a 7.a 8.5a BL 5a 57.a 8.6a.7a BL 8a 9.5a 8.9a.5a RL 5a 56.5a 8.9a.a RL a 8.a 9.a.a RL a 57.a.5a 7.7a * Numbers in the same column followed by different letters differ significantly at the probability level P<.5 according to the Tuckey s multiple range test Extractable Fe was decreased from the first to the second year after liming and tented to increase again in the third year (Figure ). This trend was in the opposite direction of the trend of soil ph, with which extractable Fe was strongly correlated in a negative way (Figure ). This negative relationship between soil ph and available Fe was in close agreement with those reported by Schwab et al. (99). However, DTPA extractable Fe was not found to be a good predictor of the available soil Fe. The correlations between soil Fe and Fe concentration in dry matter of wheat as well as between soil ph and Fe concentration in wheat tissue were not significant. Furthermore, Fe concentration in wheat tissue was not significantly affected by soil ph changes due to soil liming. Extractable Zn was significantly decreased because of the liming. From.75 mg kg - soil in the control treatment it was reduced to.7 and.59 mg kg - soil in the treatments A and B respectively (data not presented). Zinc concentrations did not differ in the years 995 and 997 (data for the year 996 are not available). Soil Zn concentration was weakly correlated with soil ph (Figure ). In addition, soil Zn concentration was not significantly correlated with Zn in wheat tissue concentration, suggesting that DTPA test is not efficient for prediction of available Zn to wheat in the soil studied. Zinc does not show similar to Fe and Mn trend in soils in relation to soil ph. Schwab et al. (99) found that Zn strongly interacted with N and P in soils showing a positive relationship with soil ph. They finally suggested that ph, P and DTPA extractable Zn are related to the chemistry of the extracting solution rather than the soil chemistry of Zn. Extractable copper was not significantly affected by the liming. However, a significant decrease was observed from the first to the two subsequent years (Figure ). These findings are not in agreement with those reported by Follet and Lindsay (97) who found that extractable Cu was lost slowly during a period of weeks after Cu-fertilizer application. Extractable Cu showed a weak negative relationship with soil ph (Figure ). In addition, concentration of soil Cu was not significantly correlated with Cu concentration in wheat tissue. change after liming did not significantly affect Cu concentration in wheat tissue. Conclusion Liming of strongly acid soils with 5 ton ha - refuse lime or 6.5 ton ha - burned lime can keep soil ph in desirable level for at least three years. During this period Mn and Cu

5 continue to decrease while Fe tends to increase in the third year following a decrease in the second year. Acknowledgments This work was partially financed by the Hellenic Sugar Industry. References Folley, R.H. and Lindasy, W.L. 97. Changes in DTPA-extractable zinc, iron, manganese, and copper in soils following fertilization. Soil Sci. Soc. Am. Proc. 5:6-6. Homshmad, A.R. 99. Experimental research design and analysis, a practical approach for agricultural and natural sciences. CRC Press, London. pp. 8. Lindsay, W.L. and Norvell, W.A Development of a DTPA soil test for zinc, iron, manganese, and copper. Soil Sci. Soc. Am. J. :-. McLean, E.O. 98. and Lime Requirements. In A.L. Page (ed.) Methods of Soil Analysis, Part, Chemical and Microbiological Properties, nd ed. No 9 Agronomy, ASA, SSSA, Mad. wisc. USA. pp Mills, H.A. and Jones, J.B. Jr Plant analysis handbook II, a practical sampling, preparation, analysis, and interpretaion guide. MicroMacro Publishing Inc. pp.. Schwab, A.P., Owensby, C.E., and Kulyigyong, S. 99. Changes in soil chemical properties due to years of fertilization. Soil Sci. 9():5-. Tsadilas, C.D effect on the distribution of heavy metals among soil fractions. Proceedings of the Fourth International Conference on the Biogeochemistry of Trace Elements, June -6, 997, Berkeley, California. pp Tsadilas, C.D., Samaras, V., Varvarousis, J., and Maslaris, N Liming of acid soils. I. Influence on wheat yield. Proceedings of the XVIII Grasslands Congress, June 8-9, 997, Winnipeg, Manitoba, Saskatoon, Saskatchewan, Canada (in press). Keywords: soil ph, DTPA extractable metals, soil liming, iron, zinc, manganese, copper, liming Mots clés : sol, fer,, zinc, manganèse, cuivre, chaulage, DTPA 5

6 Mn-DTPA, mg kg C A A A B B B Zn-DTPA, mg kg -,5,5,5,5 C A A A B B B Fe-DTPA, mg kg Cu-DTPA, mg kg - 5 C A A A B B B C A A A B B B Figure. Variation of DTPA extractable Mn, Zn, Fe and Cu during the three years Mn-DTPA, mg kg - 5 y = 56.5x -.9 R =.65*** Mn-DTPA, mg kg y =.67x -.7 R =.5* Fe-DTPA, mg kg y = -.5x R =.5*** Cu-DTPA, mg kg -,,,8,6,, y = -.9x +. R =.5* Figure. Relationship between soil ph and concentration of metals extracted by DTPA 6