Behaviour of oxifluorfen in soils amended with different sources of organic matter and subjected to severe drought

Abstract

The objective of this work was to study the effect of two organic amendments in soils contaminated with oxyfluorfen and submitted to severe drought. Two groups of treatments were arranged. One of them was watered during the experimental period and the other was maintained dry. The results obtained shown that dehydrogenase activity was lower in dry soils compared with those watered for all the treatments. Oxyfluorfen made dehydrogenase activity decrease in both scenarios. The addition of organic matter supposed an increase of this parameter, being higher in soils with MS compared with MC. This behaviour could be due to the content of fulvic acid, which were higher in MS than in MC. Fulvic acids are the more labile fraction of organic matter and, therefore, more available for microorganisms. On the other hand, MS has a bigger content of humic acid, which played a key role in the adsorption of oxyfluorfen, making the xenobiotic less available for soil microbes. Likewise, a higher degradation of oxyfluorfen was observed in soils amended with MS than those with MC, either in watered or not watered soils.