Cover Crops for Weed Suppression
Winter cover crops compete with weeds for light, moisture, and nutrients. When cover crops are killed, they produce a soil-covering mulch, which can inhibit weed germination. In addition, some cover crops may release chemicals which further inhibit weed seed germination.
Greater cover crop biomass leads to a thicker mulch layer, and thus better weed control. Earlier cover crop planting and later cover crop termination increases cover crop biomass. In organic reduced-tillage systems, mechanically killed cover crops can suppress weeds that would otherwise be controlled with tillage and cultivation. However, the efficacy of cover crop termination also depends on termination timing.