Smaller agricultural fields, more edges, and natural habitats reduce herbicide-resistant weeds

Abstract

The exponential growth of herbicide-resistant weeds poses enormous challenges to the sustainability of food systems. While great efforts in weed management are being performed at the plot level, the influence of the landscape context on the presence of herbicide-resistant weeds remains largely unknown. We tested these ideas through a large-scale sampling on two of the most important crops globally: maize and soybean. In Argentina, we co-developed with farmers the sampling of 2846 soybean and 1539 maize fields (covering an area of 159 million ha) and measured the presence of herbicide-resistant weeds, landscape context (field size, edge density, natural habitat size), management variables (e.g. fertilization), crop variety, farm identity and region. We found that smaller fields, with higher edge density, and neighboring larger natural habitats were associated to a lower presence of herbicide-resistant weeds. These results were not confounded with the influence of some other management variables (e.g. fertilization), crop variety, farm or region. Landscape design is an important, but underrepresented, management tool that could help to achieve a sustainable control of weeds.