Efecto de la Aplicación de Herbicidas en Condiciones de Campo Sobre Algunas Actividades Biológicas

Abstract

Some recent research has indicated that the use of herbicides can cause different effects on soil biological activities. However, most of these studies have been conducted in laboratory conditions without considering field conditions. In view of this, an experiment was carried out on andisol soil with the purpose of ascertaining the effect of different herbicides applied on traditional anual crops in southern Chile upon microbial biomass and some enzyme activities. The crops and herbicides applied in each case were wheat-MCPA+metsulfuron-methyl, lupin-simazine, oil rape-trifluraline and a control without applying any herbicides. Microbial biomass C and N were affected negatively by trifluralin and MCPA+metsulfuron methyl. In general, all enzyme activities were negatively affected by the different herbicide treatments in the first and second sampling in relation to the control. Dehydrogenase activity, was observed a significant reduction in relation to the control after applying the different herbicides on the different crops in the first and second sampling. As for the acid phosphatase activity the same tendency toward dehydrogenase activity was observed in the simazine treatment. In the case of urease activity, a significant reduction was observed in the third and fourth sampling in relation to the witness treatment. In general, the enzyme activities were also conditioned by the crops that each treatment was applied on. Therefore, it is interesting to continue studying the relation between enzyme activities and the different agricultural managements including the application of herbicides.