Cover crops

Cover crops can suppress many weeds through competition for light and nutrients or allelopathy. Covers may also control disease and insects in soil since non susceptible plants inter-planted with susceptible species may intercept pathogen inoculum or insect pests. Various nematode species may be affected by a cover crop, but others are not. Rye and timothy, among other cover crops, are able to release substances with nematicidal effect  during their decomposition. Cover crops may also reduce nitrate leaching and runoff water from fields.