Minimizing pesticide runoff by grass buffer strips - experiments with simulated rainfall.

摘要

Rainfall simulation experiments were carried out on two different experimental sites in Germany with the aim of analysing the influence of buffer strip width, buffer strip condition, and pesticide properties on the filtering efficacy of grass bufferstrips. Mecoprop, isoproturon, pirimicarb, terbuthylazine, fenpropimorph and pendimethalin were selected as model pesticides due to their great span in physico-chemical properties. Applications were conducted in a simulated pre-emergence treatment 24 hours before the start of simulation. In a single runoff event, between 0.1% and 13% of the pesticide amount applied were exported from the treated area. Losses of pesticides with a Koc < 100 (mecoprop, pirimicarb) occurred completely through water transport. Buffer strip efficacy increased with increasing strip width, and was highest for pesticides with high Koc-values (pendimethalin, fenpropimorph). Infiltration and sedimentation were identified as the main mechanisms to reduce pesticide runoff, however, for pendimethalin also adsorption processes could be detected.