The Effects of composts on adsorption-desorption of three carbamate pesticides in different soils of Aligarh district

The effects of various organic manure [farm yield manure (FYM), sewage sludge and poultry manure] application on adsorption-desorption of three carbamate pesticides [oxamyl(I);S-Ethyl-Nmethylcarbamoyl)oxy]thioacetimidate (II) and N-Phenyl (ethyl carbamoyl) propyl carbamate (III) on six soil samples of Aligarh district was studied. Addition of organic manure increased soil organic carbon content and electrical conductance while pH decreased. The results of the study denoted that adsorption isotherms were ‘L’ type and adsorption-desorption data conformed to Freundlich adsorption isotherm equation. The adsorption increased with the increase in organic manure and followed the order sewage sludge > FYM > poultry manure. The adsorptivity of soils was in order soil No. 1 > 2 > 3 > 4 > 5 > 6. The adsorption capacity was significantly positively correlated with soil organic carbon and CEC and negatively correlated with soil pH. Desorption was more in unamended soil than manure amended soil and decreased with the increase in amount of organic manure. Desorption showed hystersis, indicate by the higher adsorption slope (1/n ads) compared with desorption slope (1/n des). @JASEM Pesticides adsorption and desorption are the key processes determining whether pesticide used will have any impact on environmental quality. For most of the pesticides soil organic matter and clay contents are the most important properties which affect the sorption and transformation (Durovic et al., 2009; Osborn et al., 2009; Villavarde et al., 2008). The use of composts derived from source-separated municipal solid waste/animal manure/FYM is now a common agronomic practice throughout the world. Such amendments improve the physico-chemical properties of the soil. Application of such composts affect the fate and mobility of applied pesticides in soil as addition of compost increases besides nutrients the soil organic matter content (Paustin et al., 1992). Carbamate pesticides are widely used as insecticides, nematicides and herbicides (Hague, 1979). Investigations on the adsorption of carbamate pesticides by clays have shown that they are adsorbed by co-ordination and/or protonation at the carbonyl oxygen by exchangeable cations of clays (Bansal 2009, 1983; Li et al., 2003). The purpose of the present study is to study the effect of different amount of organic manure (FYM, sewage sludge and poultry manure) on the extent of adsorption/desorption of three polar water soluble carbamate pesticides; oxamyl (I) [methyl-2-(dimethylamine)-N-{(methyl amino) carbonyl}oxy]-2-oxoethanimidothioate (CH3)2NCO(SCH3)=NOCOCH3; S-Ethyl-N(methylcarbamoyl)oxy]thioacetimidate (II) CH3-NHCO-N=C(CH3) (SCH3); and N-Phenyl (ethyl carbamoyl) propyl carbamate (III) (C6H5NHCOOCH(CH3)CONHC3H7 in six soils of Aligarh district. MATERIAL AND METHODS The six soils (1-6) selected for this study were taken from different parts of Aligarh district at plough layer (0-30 cm). They were air dried at room temperature and sieved by passing through a 100 mesh sieve. Their physico-chemical properties were determined by the usual soil laboratory methodology and clay mineralogy by an X-ray diffraction procedure on orientated specimen. Physico-chemical properties, clay mineralogy and classification are given in Table 1. Table 1. Characteristics of soils S/No Place Taxonomical name Soil units Silt % Clay % pH (1:2:5) Organic C % CaCO3 % CEC (Cmol (P) kg) Surface area mg Major clay minerals 1. A Entisol Typic Ustochrept 38.8 16.2 7.8 0.88 6.3 12.8 38.6 Q,I,C 2. B Acidisol Typic Arigids 52.0 14.0 8.8 0.72 7.6 11.6 36.2 Q,I,C 3. C Aridisol Typic Orthids 37.5 12.0 7.4 0.63 5.8 10. 8 30.1 Q,M,I,C 4. D Aridisol Typic Orthids 44.9 13.6 7.6 0.56 6.6 10.3 27.2 Q,I,C 5. E Aftisol Calciorthents 24.9 9.8 8.3 0.44 8.8 9.9 32.1 Q,I,K,C 6. F Inceptisol Calciorthents 27.1 8.5 8.1 7.9 7.6 6.9 0.48 23.3 26.6 20.2 9.0 8.6 42 46 38 25.6 Q,I,K,C A = Hathras; B = Sikandra Rao; C = Datawali; D Khair = ; E = Atrauli; F = Bank of Yamuna Tappal FYM Sewage sludge Poultry manure; Q = Quartz, I – Illite, M = ontmorillonite, C = Calcite, K = Kaolinite Soil amendment : Soils (1-6) were amended with 0, 2.5 and 5 g of organic manure (FYM, sewage sludge and poultry manure) kg -1 soil at 60% moisture level of water holding capacity and incubated for 45d at the temperature 25±2 o C. The physico-chemical properties of amended soils as determined by standard methods are given in Table 2. The Effects of composts on adsorption-desorption..... BANSAL, O P Table 2. Effect of application on organic material on soil properties Organic material added g kg soil Soil 1 Soil 2 Soil 3 Soil 4 Soil 5 Soil 6 pH OC g kg 1 EC dSm 1 pH OC g kg 1 EC dSm 1 pH OC g kg 1 EC dSm 1 pH OC g kg EC dSm 1 pH OC g kg EC dSm 1 pH OC g kg EC dSm 1 Sewage sludge 0 7.8 8.8 0.66 8.8 7.2 0.61 7.4 6.3 0.55 7.6 5.6 0.57 8.3 4.5 0.52 8.1 4.8 0.44 2.5 7.7 10.6 0.73 8.5 9.9 0.67 7.3 8.9 0.59 7.4 8.1 0.59 8.1 7.0 0.56 8.0 7.5 0.49 5.0 7.5 11.7 0.78 8.1 11.0 0.71 7.2 10.0 0.66 7.1 9.3 0.63 7.8 8.1 0.60 7.7 8.0 0.53 FYM 0 7.8 8.8 0.66 8.8 7.2 0.61 7.4 6.3 0.55 7.6 5.6 0.57 8.3 4.5 0.52 8.1 4.8 0.44 2.5 7.7 10.3 0.71 8.5 9.7 0.68 7.4 8.7 0.57 7.4 8.0 0.58 8.1 6.9 0.55 7.9 7.2 0.48 5.0 7.6 11.4 0.76 8.2 10.7 0.70 7.3 9.8 0.63 7.2 9.1 0.62 7.8 8.0 0.60 7.7 7.9 0.52 Poultry manure 0 7.8 8.8 0.66 8.8 7.2 0.61 7.4 6.3 0.55 7.6 5.6 0.57 8.3 4.5 0.62 8.1 4.8 0.44 2.5 7.7 10.0 0.70 8.5 9.6 0.66 7.4 8.6 0.57 7.5 7.8 0.60 8.2 6.8 0.55 7.9 7.2 0.47 5.0 7.7 11.0 0.73 8.2 10.5 0.69 7.2 9.6 0.62 7.2 8.9 0.61 7.9 7.8 0.58 7.8 7.8 0.50