Conservation compliance credit for winter wheat fall biomass production and implications for grain yield

ABSTRACT:

Producers participating in federal farm and conservation programs must reduce potential erodibility below certain thresholds on lands classified as highly erodible. The Natural Resource Conservation Service (NRCS) will credit producers in Colorado for the quantity of green winter wheat (Triticum aestivum L.) biomass at the beginning of the winter period towards compliance in reducing erosion. Unfortunately, few data exist on fall winter wheat biomass production, and fall production varies widely based on many site-specific factors at planting and during the fall, and can be expensive to document. To address these problems, a crop simulation model called SHOOTGRO was used to predict the amount of green biomass present. By combining planting dates, sowing rates, and conditions of NO₃, NH₄, total water in the soil profile, and water in the seedbed layer at planting for three sites in eastern Colorado a total of 216 scenarios were simulated, both to assist NRCS in determining compliance and to better understand the dynamics of early winter wheat biomass production.