Rotating out of weeds and into soil health: Optimizing cover crops in three Columbia Basin organic production systems

Weeds cause extensive loss in agricultural production and are particularly damaging in organic systems. Control generally relies on mechanical cultivation which reduces soil carbon, decimates soil fauna, and increases erosion potential. Cover cropping, a biologically intensive practice, can be an effective tool to reduce weed pressure and improve soil quality, but it also introduces new challenges as failed or marginal cover crop plantings create fertile ground for opportunistic weeds. This project will optimize use of summer cover crops in three different Columbia Basin production systems with three different on-farm experiments: 1) Sudangrass incorporated into a grazing and grain system, 2) planting dates and rates for Sudangrass, mustard, and mixes preceding onions, and 3) companion planted crops for carrot seed production. In addition to cover crop and cash crop performance, soil health and weed pressure will be analyzed in replicated on-farm experiments allowing us to describe soil quality and weed populations in multiple organic agro-ecosystems across the Columbia Basin.