Sorption-Desorption of Alachlor and Linuron in a Semiarid Soil As Influenced by Organic Matter Properties after 16 Years of Periodic Inputs

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• 作者：José ; Dorado ; Cristina Ló ; pez-Fando ; Marí ; a-Cristina Zancada ; and Gonzalo Almendros
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2005
• 出版时间：June 29, 2005
• 年：2005
• 卷：53
• 期：13
• 页码：5359 - 5365
• 全文大小：90K
• 年卷期：v.53,no.13(June 29, 2005)
• ISSN：1520-5118

文摘

The effect of management practices on soil potential for regulating the residual concentration ofpesticides was examined in samples from a Calcic Haploxeralf in Toledo (central Spain). Sorption-desorption of alachlor and linuron was found to depend on inputs of lignocelullosic wastes or cattlemanure for the past 16 years. For a given herbicide, the soil sorption capacity (K_f) follows the ordercontrol < crop residues < manure, which is consistent with the organic C content in the soil samples.Some structural characteristics of the soil humic acid as revealed by visible and infrared spectroscopiesand analytical pyrolysis were useful to forecast the sorption-desorption intensity. Simple and multiplelinear correlation analyses illustrate enhanced sorption of alachlor and linuron in soil plots whereslightly altered soil organic matter accumulated (positive correlations with the intensity of infraredlignin signature band and with the methoxyphenol yields after pyrolysis of the humic acids and negativecorrelation with the aromaticity as pointed out by the optical density at 465 nm). Linuron showed apreference for soils with humic acids of low molecular weight and low degree of internal cross-linking,as inferred from the positive correlation with the ratio between optical densities at 465 and 665 nm.Under the conditions of the present experiment, agricultural practices including organic amendmentsseem to have a beneficial effect in the control of leaching and sorption of pesticides.Keywords: Herbicides; organic matter; humic acid; regression models