Cover Crops Increase Destruction of Weed Seed in Fields, Shed Light on Predator Interactions
Cover crops have been promoted for their abilities to reduce erosion and retain or enhance soil nutrients. Now there is evidence that they can significantly reduce weed seeds from entering the soil seed bank. Crops such as red clover, planted after a main crop’s harvest, often are used to provide cover for insects such as ground beetles that feed on weed seed scattered along the soil surface. Beetles remove the seeds before they are tilled under and become part of the field’s long-term seed bank. Rodents are also important consumers of weed seeds and, like beetles, tend to prefer foraging under the shelter provided by cover.
Illustration Photo: Cover cropping at Granton Vineyard. This image shows fava beans planted in alternate vineyard rows. The beans are slashed and raked under the vines to allow the biomass to break down over time and provide a source of valuable soil nutrient, including nitrogen. (credits: Stefano Lubiana / Flickr Creative Commons Attribution 2.0 Generic (CC BY 2.0))