Does soil organic matter chemistry affect sorption of nonionic pesticides?

The influence of organic matter chemistry on the sorption of diuron to soils collected from a small field was investigated. Organic carbon-normalized sorption coefficients (KOC), determined by batch sorption, varied between 405 and 598 Lkg-1 amongst 10 A11 horizons, and between 547 and 975 Lkg-1 amongst 10 matching A12 horizons. In all cases KOC was greater for the A12 horizon than the corresponding A11 horizon by 27-81%. Organic matter chemistry of the A11 and A12 horizons was determined using solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. KOC was positively correlated with aryl C (r2 = 0.61, significance level 0.001) and negatively correlated with O-alkyl C (r2 = 0.88, significance level <0.001) as a single factor and combination of both we also propose A index (r2 = 0.65, significance level 0.001). Little changes in soil mineralogy across a very small field led to diminish organic matter and clay minerals interactions, allowing the effect of organic matter chemistry on KOC to be seen clearly.

کلیدواژه ها:

sorption ، diuron ، NMR spectroscopy