SEED COTTON YIELD AND NUTRIENT CONCENTRATIONS AS INFLUENCED BY LIGNITIC COAL DERIVED HUMIC ACID IN SALT-AFFECTED SOILS

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1 Sarhad J. Agric. Vol.26, No.1, 2010 SEED COTTON YIELD AND NUTRIENT CONCENTRATIONS AS INFLUENCED BY LIGNITIC COAL DERIVED HUMIC ACID IN SALT-AFFECTED SOILS HAROON, RIAZ A. KHATTAK and DOST MUHAMMAD Department of Soil and Environmental Sciences, NWFP Agricultural University, Peshawar Pakistan. ABSTRACT Humic acid (HA) can supplement the chemical fertilizers to reduce the input cost of agricultural production. Field experiments on increasing cotton [Gossipium hirsutum L, cv. CIM-473] crop yield through HA were conducted in salt-affected soil of Kohat division, NWFP, Pakistan, during Kharif 2005 at two sites being irrigated with tube-well saline waters. Four levels of humic acid (0, 0.5, 1.0 and 2.0 kg ha -1 ) were applied alone or with recommended dose of NPK (90:60:30 kg N:P 2 O 5 :K 2 O ha -1 ). Results showed that seed cotton yield (seed+cotton fiber) significantly (P< 0.05) responded to both HA and NPK levels at both sites. When averaged across levels of NPK, application of 0.5, 1.0 and 2.0 kg ha -1 HA increased seed cotton yield by 10.5, 15.6 and 13.5 at site 1 and 12.2, 17.7 and 21.2 % at site 2 as compared to control while such increases reached to 30.5, 42.5 and 35.3 % at site 1 and 23.4, 37.7 and 31.1 % at site 2 when the same HA levels were applied with NPK. Combine application of 0.5, 1.0 and 2.0 kg HA ha -1 plus NPK enhanced seed cotton yields by 9.01, and % at site 1 and 5.02, and %, in site 2, respectively as compared to plots receiving NPK (90:60:30 kg ha -1 ) alone. The seed cotton yield increased by at site 1 and % with NPK as compared with control. The results suggested that addition of 1.0 kg ha -1 could supplement NPK fertilizer and enhance farmer s income by increasing yield in arid zone salt affected soils. Key Words: Humic acid, cotton, chemical composition, salt-affected soils Citation: Haroon, R.A. Khattak and D. Muhammad Seed cotton yield and nutrient concentrations as influenced by lignitic coal derived humic acid in salt-affected soils. Sarhad J. Agric. 26(1): INTRODUCTION The supplementation of chemical fertilizers with cheaper lignitic coal derived humic acid could reduce cost of production without compromising on yield. Humic acid (HA) is a natural product, which is present in Pakistan s lignitic coal in reasonable concentrations and is used in agriculture and industry but on limited scale (Hai and Mir, 1998). Humic substances are formed through the process of humification of organic materials as by-product of microbial metabolism and are found in soil, coal, sediments water, peat, and organic matter (Stevenson, 1994). HA is a complex molecule and is considered an alkali soluble, polymeric organic acid of aromatic structure substituted by carboxyl, phenolic, hydroxyl and alkyl groups linked together through ester linkages (Gaines and Yilmaz 1983). The critical review by Sutton and Sposito (2005) on the molecular structure of humic substances in soil, presented a new view on the basis of published data obtained from NMR spectroscopy, X-ray absorption near-edge structure spectroscopy and pyrolysis. According to their view, humic substances are clusters of diverse, relatively small organic molecules linked by H + bonds and hydrophobic interactions. Although the structural aspects are still under intense investigation, the various beneficial effects of HA on crops have been reported. Depending upon the origin, molecular size, chemical characteristics and concentrations, humic substances are implicated in a range of different metabolic effects on plant (Nardi et al., 2002a; Tan, 2003). These substances may enter into plant, translocate from roots to shoots (Vaughan and MacDonald 1976; Nardi et al., 1996) and affect plant growth by different mechanisms such as increasing respiration (Vaughan et al., 1985), enhancing microbial nutrition (Clapp et al., 2001; Varanini and Pinton, 2001), stimulating hormones activities (Vaughan et al., 1985; Nardi et al., 2002b), increasing enzymes activities (Nardi et al., 2007) and energy relation (Zancani et al., 2009).

2 Haroon et al. Seed cotton yield and nutrient concentrations as influenced by lignitic coal Salt toxicity is one of the major factors limiting crop production and environmental quality in saline and/or sodic soils throughout the world (Pitman and Läuchli, 2004). Excessive amounts of salts adversely affect the physical and chemical properties of soil, microbiological processes and plant growth (Mer et al., 2000; Ramoliya and Pandey, 2003). Salt affected soils occur commonly in arid and semi-arid regions have low crop productivity due to excessive accumulation of salts in the root zone. The underground water of these regions are usually saline sodic and with continuous saline irrigation and high evaporation more salts are accumulated in the soil (Bohn et al., 2001). Out of total 80 million hectares land of Pakistan about 6.3 million hectares are salt affected (Qureshi and Barrett-Lennard, 1998). The farmers of these areas confront problems of low soil fertility confounded by limited socio-economic resources with little scientific, technological and institutional support and guidance. Experiments on normal calcareous irrigated soil in Peshawar showed that application of lignitic coal derived HA increased maize and wheat yield from 25 to 40% (Sharif et al., 2002a., 2002 b). Cotton being salt tolerant crop is grown on large area of Pakistan. This study aims to asses the degree and extent of the use of HA as a low cost organic supplement to costly chemical fertilizer to enhance cotton yield in salt affected soils. MATERIALS AND METHODS The study on increasing seed cotton yield through humic acid was conducted in salt-affected soil of Kohat division, NWFP, Pakistan, during Kharif 2005 on Nasimabad (Site 1) and Jalalabad (Site 2). Four levels of humic acid (0, 0.5, 1.0 and 2.0 kg ha -1 ) were applied alone or with recommended dose of NPK (90:60:30 kg N:P 2 O 5 :K 2 O ha -1 ). Urea, triple super phosphate (TSP) and sulfate of potash (SOP) were used as sources for N, P and K, respectively. The experiment was arranged in 4x2 Factorial Randomized Complete Block Design (RCBD) with three replications and eight treatments. Fertilizers were applied through broadcast immediately followed by ridge formation at field water conditions. The required humic acid was applied in sand mixture over the ridges followed by proper mixing with the soil. Cotton variety CIM-473 was sown on ridge with ridge to ridge distance of 70 cm and plant to plant distance of 20 cm. At each spot two-three seeds were sown which were then thinned to single seedling after germination. Before humic acid or fertilizer application and ridge formation, soil samples were collected from 0-15 cm depth for pre-sowing soil chemical analysis. After crop harvest soil samples were collected from each treatment plot for post harvest soil analysis. Cotton leaves at crop maturity when more than 50% bolls were opened were also collected for nutrient uptake as influenced by different levels of humic acid and fertilizers. Physico-chemical properties were determined by the given procedure; soil texture (Gee and Bauder, 1986), soil ph (Thomas, 1996), EC (Rhodes, 1996), Na by flame photometery, Ca+ Mg by titration (US Salinity Staff, 1954) and soil organic matter (Nelson and Sommers, 1996). The AB-DTPA extractable P was extracted by the method as described by Soltanpour and Schawab (1977) and determined through ammonium molybdate color complex using spectrophotometer (Perking Elmer, Lambda 35), and KCl extracted N (mineral nitrogen) by the procedure of Mulvaney (1996). Plant leaf samples were analyzed for Cu, Zn, Fe and Mn through atomic absorption spectrophotometer (Perkin Elmer, 2380) after acid digestion following the method of Jones et al. (1991). RESULTS AND DISCUSSION Pre-sowing Soil Physico-chemical Properties The pre-sowing physical and chemical properties (Table I) indicate that both sites 1 and 2 were alkaline, strongly calcareous, low in organic matter and mineral N. Site 2, silt loam was marginally sodic contained higher (5.31±0.72 mg kg -1 ) AB-DTPA extractable P than site 1 which was silty clay loam and contained low P (1.36±0.50 mg kg -1 ).

3 Sarhad J. Agric. Vol.26, No.1, Seed Cotton Yield at Site 1 and 2 Statistical analysis of the data according to 4 x 2 factorial design with split plot arrangement revealed that seed cotton yield (seed+cotton fiber) significantly (P< 0.05) responded to both HA and NPK levels at both sites analyzed separately as well as combined over sites, however interactions between HA x NPK, sites x HA were nonsignificant (Table II). When averaged across levels of NPK, application of different levels of HA significantly (P<0.05) increased the seed cotton yield over plots where no HA was applied (Table II). Sole application of 0.5, 1.0 and 2.0 kg ha -1 HA increased seed cotton yield by 10.5, 15.6 and 13.5 at site 1 and 12.2, 17.7 and 21.2 % at site 2 as compared to control while such increases reached to 30.5, 42.5 and 35.3 % at site 1 and 23.4, 37.7 and 31.1 % at site 2 when the same HA levels were applied with NPK. As such combined application of 0.5, 1.0 and 2.0 kg HA ha -1 plus NPK enhanced seed cotton yields by 9.01, and % at site 1 and 5.02, and %, in site 2, respectively over plots receiving NPK (90:60:30 kg ha -1 ) alone. The seed cotton yield increased by at site 1 and % with NPK as compared with control (No NPK and HA). The perusal of the data on seed cotton yield suggested that the highest dose of 1.0 kg ha -1 +NPK gave the highest yield ha -1 (Table III, Fig. I). Therefore, application of HA at the rate of 1.0 kg ha -1 plus NPK is the appropriate dose for cotton under the given salt-affected soils of the area. The combined application of HA with NPK demonstrated substantial additive beneficial effect as evident from seed cotton yield with 19.0% increase over NPK alone and up to 41.1% over control. Results are in line with reports of other researchers. Xue et al. (1994) observed superior performance of HA compound fertilizer in maize, wheat, cotton, rape and sesame production as compared to equivalent diammonium phosphate and other chemical fertilizers. It increased resistance to drought, cold, and diseases resulting in overall improvement in crop yield and accumulation of nutrients. Several other researchers have also reported increases in plant growth and yield with application of HA both in pot and field experiments ( Malik et al., 1979; Brannon and Sommers, 1985; Hai and Mir, 1998). Humic acid induced increases in plant growth on sustainable basis are associated to its effect on root enzymes and rhizosphere soil (Vaughan and MacDonald, 1976; Malcolm and Vaughan, 1979). Post Harvest Soil Chemical Composition The effect of HA and NPK treatments was non-significant on soil ph, EC e and SAR (Table IV). The ph values ranged from 7.94 to 8.18, EC e from 9.86 to dsm -1, and SAR from to at site 1 and from 7.81 to 8.06, from 8.05 to 9.59 and 8.14 to 10.35, respectively in site 2 (Table IV). Since both sites received saline irrigation waters with EC iw above 6.0 and SAR above 10.0, values of post harvest soil EC e and SAR increased with cropping. The increases in the values of EC e and SAR as compared to pre-sowing values were obviously associated with quality of irrigation water that was further accentuated by limited leaching due to low rainfall and higher evapo-transpiration during the summer season. The higher values of EC e and SAR in the site 1 were mainly because of irrigation water having higher EC e and SAR and higher clay content as compared to site 2. Micronutrient Concentration in Cotton Leaves The analyses of variance showed significant (p < 0.01) effect of sites on Cu and Fe concentration in cotton leaves while effect of HA, NPK and all interactions were non-significant. When data were averaged across NPK and sites, Cu, Zn, Fe and Mn concentrations inconsistently varied with different levels of HA manifesting the dilution effect due to variations in yields (Table V). The concentrations of Cu in leaves ranging from 9.93 to mg kg -1 could be low and Zn concentrations varying from to may be marginally sufficient (Jones et al., 1991). The concentrations of Fe and Mn in plant tissues were adequate in both sites 1 and 2. Data suggested that the cotton crop yield may be limited by Cu and Zn to some extent in these salt affected soils. Xue et al. (1994) observed increased nutrient uptake by maize, wheat, cotton, rape and sesame with HA compound fertilizer as compared to equivalent diammonium phosphate and chemical fertilizers. Cheng (1977) postulated that HA increases the permeability of the cell membranes which results in increased uptake of moisture and nutrient elements. Sharif et al. (2002 a) observed non-significant changes in micronutrient concentrations in maize leaves with addition of HA ranging from 0 to 300 µg kg -1 in pot experiments but when the concentrations were converted to total nutrient accumulation, the effect of HA treatments was significant. In other field experiments conducted on wheat, maize and sugar beet as component of this study revealed consistent increases in total uptake of micronutrients with increasing levels of HA when nutrients concentrations were converted to total nutrients uptake.

4 Haroon et al. Seed cotton yield and nutrient concentrations as influenced by lignitic coal Table I Pre-sowing soil physico-chemical properties of cotton field at site 1 and 2 during kharif 2005 Soil parameters Mean±SD Site 1 Site 2 ph 8.34± ±0.11 EC e (dsm -1 ) 5.86± ±0.16 SAR 15.41± ±0.29 Lime (%) 16.56± ±0.16 SOM (%) 0.91± ±0.18 AB-DTPA ext. P mg kg ± ±0.72 Mineral N mg kg ± ±2.87 Textural Class silty clay loam silt loam Table II ANOVA of seed cotton yield at site 1 and 2 and combined over two sites (F values) SOV D.F. Site-1 Site 2 Combined Seed cotton yield Site *** Replications 2 (4)# 0.78ns 2.06ns 1.45ns HA levels * 3.72* 7.96*** Sites x HA ns NPK ** 10.47** 38.79** HA X NPK ns 0.36ns 0.44ns Error Total SS CV (b) # D.F for Replication and location *, **, *** significant at P < 0.05, < 0.01, and ns= non-significant Table III Seed cotton yield (kg ha -1 ) at site 1 and 2 as influenced by different levels of HA with or with out NPK in saltaffected soils during kharif 2005 HA Site 1 Site 2 (kg ha -1 ) - NPK + NPK Mean - NPK + NPK Mean b b ab ab a a a a Mean 642 b 771 a b 671 a - Averaged across sites c b a ab Mean 617 b 721 a - LSD 0.05 for seed cotton = for site 1, 74.0 for site 2, and kg ha -1 for combined analysis, respectively. NPK added at the rate of 90:60:30 kg N:P 2 O 5 :K 2 O ha -1. Table IV Post harvest soil ph, EC and SAR of cotton plot as influenced by HA and fertilizer during 2005 Treatments Site 1 Site 2 HA NPK phe ECe SAR phe ECe SAR (kg ha -1 ) - dsm dsm :0: :60:

5 Sarhad J. Agric. Vol.26, No.1, Table V Concentrations of Cu, Zn, Fe and Mn (mg kg -1 ) in cotton leaf tissues as influenced by HA applied with and without NPK under salt affected soils at site 1 and 2 during kharif 2005 Treatments Site 1 Site 2 HA NPK Cu Zn Fe Mn Cu Zn Fe Mn kg ha -1 ) mg kg :0: :60: Averaged across sites and NPK levels (2 site x 2 NPK levels) Averaged across Humic acid and sites (4 HA x 2 site) 0:0: :60: Seed cotton yield (kg ha -1 ) w ithout NPK w ith NPK HA level (kg ha -1 ) Fig. 1 Seed cotton yield as affected by HA application with and without NPK (averaged across site1 and 2) under salt affected soils during kharif 2005 CONCLUSION The substantial increase in seed cotton yield with combined application of 1.0 kg HA ha -1 with NPK over alone NPK revealed additive effect of HA. This suggest that supplementation of chemical fertilizer with humic acid could reduce the cost of production without compromise on yield and thus could increase the farmer s income.

6 Haroon et al. Seed cotton yield and nutrient concentrations as influenced by lignitic coal REFERENCES Bohn, H.L., B.L. McNeal and G.A. O Gonnor Soil Chemistry. 3 rd Ed. John Wiley and Sons, Inc. New York. Brannon, C.A. and L.E. Sommers Preparation and characterization of model humic polymers containing organic Phosphorus. Soil Biol. & Biochem. 17: Cheng, B.T Soil organic matter as plant nutrients. Proc. of Int l. Symp. Soil Organic Matter Studies, 1, IAEA, Vienna. Clapp, C.E., Y. Chen, M.H.B. Hayes and H.H. Cheng Plant growth promoting activity of humic substances. p In: R.S. Seift, K.M. Sparks (eds.). Understanding and Managing Organic Matter in Soils, Sediments and Wates. IHSS, Madison. Gaines, I. and A. Yilmaz Comparison of five Humic Acid. Fuel. 62: Gee, G.W. and J.W. Bauder Particle size analysis. p In: A. Klute (ed.). Part 1. 2 nd Ed. Method of Soil Analysis. Agron. USA. Hai, S.M. and S. Mir The lignitic coal derived HA and the prospective utilization in Pakistan s agriculture and industry. Sci, Tech. & Dev. 17: Jones, J.B. Jr., B. Wolf and H.A. Mills Plant analysis handbook. A Practical Sampling, Preparation, Analysis, and Interpretation Guide. Micro-Macro Publishing, Athens, Georgia, USA. Malcolm, R.E. and D. Vaughan Humic substances and phosphate activities in plant tissue. Soil Biol. & Biochem. 11: Malik, K.A., N.A. Bhatti and F. Kausar Effect of soil salinity on the decomposition and humification of organic matter by fungi. Mycologia. 71: Mer, R.K., P.K. Prajith, D.H. Pandya and A.N. Pandey Effect of salts on germination of seeds and growth of young plants of Hordeum vulgare, Triticum aestivum, Cicer arietinum and Brassica juncea. J. Agric. & Crop Sci. 185: Mulvaney, R.L Nitrogen-inorganic forms. p In: D.L. Sparks (ed.). Methods of Soil Analysis. Part 3. Amer. Soc. Agron., USA. Nardi, S., A. Muscolo, S. Vaccaro, S. Baiano, R. Spaccini and A. Picco Relationship between molecular characteristics of soil humic fractions and glycolytic pathway and krebs cycles in maize seedlings. Soil Biol. & Biochem. 39: Nardi, S., D. Pizzeghello, A. Muscolo and A. Vianello. 2002a. Review physiological effects of humic substances on higher plants. Soil Biol. & Biochem. 32: Nardi, S., E. Sessi, D. Pizzeghello, A. Sturato, R. Rella and G. Parvoli. 2002b. Biological activity of soil organic matter mobilized by root exudates. Chemosphere. 46: Nardi, G., G. Concheri, G. Dell Angnola and P. Scrimin Biological activity of humic substances. p In: A. Piccolo (Ed.). Humic Substances in Terrestrial Ecosystems. Elsevier, Amsterdam. Nelson, D.W. and L.E. Sommer Total C, organic C and organic matter. p In: D. L. Sparks (ed.). Method of Soil Analysis. Part 3. Amer. Soc. Agron. USA. Pitman, M.G. and A.Läuchli Global impact of salinity and agricultural ecosystems. p In: A. Läuchli and U. Lüttge (eds.). Salinity: Environment Plants Molecules. Springer Netherlands. Qureshi, R.H. and E.G. Barrett-Lennard Saline Agriculture for irrigated land in Pakistan. p. 11. A handbook. Austral. Centre for Int l Res. Canberra, Australia. Ramoliya, P.J. and A.N. Pandey Effect of salinisation of soil on emergence, growth and survival of seedlings of Cordia rothii. Forest Econ. & Mgt. 176: Rhoades, J.D Salinity: Electrical Conductivity and total dissolved solids. p In: D. L. Sparks (ed.). Method of Soil Analysis. Part. 3. Amer. Soc. Agron. USA. Sharif, M., R.A. Khattak and M.S. Sarir. 2002a. Effect of different levels of lignitic coal derived humic acid on growth of maize plants. Commun. Soil Sci. & Plant Analy. 33: Sharif, M., R.A. Khattak and M.S. Sarir. 2002b. Wheat yield and nutrients accumulation as affected by humic acid and chemical fertilizers. Sarhad J. Agric. 18: Soltanpour, P.N. and A.P. Schawab A new soil test for simultaneous extraction of soil macro and micronutrients. Commun. in Soil Sci. & Plant Analy. 8: Stevenson, F.J Humus Chemistry: Genesis, Composition, Reactions. 2 nd ed. Wiley and Sons Ltd. New York. 496 p.

7 Sarhad J. Agric. Vol.26, No.1, Sutton, R. and G. Sposito Molecular structure in soil humic substances: The new view. Envir. Sci. & Tech. 39: Tan, K.W Humic Matter in Soil and the Environment. Principles and Controversies. Marcel Dekker, New York, NY. 258p Thomas, G.W Soil ph and soil acidity. p In: D.L. Sparks (ed.). Methods of Soil Analysis. part 3. Amer. Soc. of Agron. US Salinity Staff Diagnosis and Improvement of Saline and Alkali Soils. USDA Handbook 60. US Deptt. of Agric. Washington DC. Varanini, Z. and R. Pinton Direct versus indirect effect of soil humic substances on platn growth and nutrition. p In: R. Pinton, Z. Varanin, and P. Nannipiei (Eds.).The Rhizosphere. Marcel Dekker, Basel. Vaughan, D. and I.R. MacDonald Some effects of humic acid on cation uptake by parenchyma tissue. Soil Biol. & Biochem. 8: Vaughan, D., R.E. Malcom and B.G. Ord Influence of humic substances on growth and physiological processes. pp In: D. Vaugan, and R.E. Malcom (Eds.). Soil Organic Matter and Biological Activity. Martinus Nijhoff. Dordrecht/Dr Junk. W. Publishers, Dordecht, The Netherlands. Xue, S.C., D.C. Liu., D.Y. Tong, J.M. Han and Y.R. Li Studies on the effects and mechanism of HA compound fertilizer. J. Hebei Agric. Univ. China. 17: Zancani, M., E. Petrussa, J. Krajňáková and V. Casolo Effect of humic aids on phosphate level and energetic metabolism of tobacco BY-2 suspension cell cultures. Envir. & Exper. in Bot. 65: