Effect of Vegetative Buffer Strips on Herbicide Runoff from a Nontilled Soil

Buffer strips can reduce herbicide runoff fromcultivated fields due to the ability of vegetation to impede the flow of surface runoff, promote infiltration, and adsorb herbicides. Conservation agriculture hasmany environmental advantages, but the transition phase froma conventional to a conservation systemis a critical period, especially for surface runoff. In 2015, a field in Italy that was transitioning from conventional to conservation agriculture was tested to analyze the efficacy of different types of buffer strips in reducing the runoff of three herbicides compared with no-buffer plots. At each runoff event, water volume was measured and terbuthylazine,metolachlor, and mesotrione concentrations were determined. Buffer strips were able to reduce the number of runoff events by 63% to 83%. The runoff volumes were significantly reduced in the presence of buffer strips, whereas no differences were found between different types of buffer strips. Among herbicides, mesotrione was not detected in runoff water samples. The highest losses of terbuthylazine and metolachlor were from plots without buffer strips during the first three runoff events. All types of buffer strips significantly reduced the total losses of terbuthylazine and metolachlor in the monitored runoff events, with a reduction of more than 99%. This study confirmed that buffer strips are a very effective mitigation system against surface water pollution by herbicides, even in agronomic situations that promote runoff.