Does soil organic matter chemistry have influence on the sorption of diuron?

摘要

The influence of organic matter chemistry on the sorption of diuron to soils collected from a small field (2 ha) was investigated. Organic carbon-normalized sorption coefficients (K_OC), determined by batch sorption, varied between 405 and 598 L kg-1 amongst 10 A11 horizons and between 547 and 975 L kg-1 amongst 10 matching A12 horizons. In all cases K_OC 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. K_OC 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 K_OC to be seen clearly.