CONSERVATION COMPLIANCE CREDIT FOR WINTER-WHEAT FALL BIOMASS PRODUCTION AND IMPLICATIONS FOR GRAIN-YIELD

Producers participating in federal farm and conservation programs must reduce potential erodibility below certain threshold on lands classif ied as highly erodible. The Natural Resource Conservation Service (NRC S) will credit producers in Colorado for the guantity of green winter wheat (Triticum aestivum L.) biomass at the beginning of the winter pe riod toward compliance in reducing erosion. Unfortunately few data exi st onfall 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 cr op 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 to tal of 216 scenarios were simulated, both to assist NRCS in determinin g compliance and to better understand the dynamics of early winter whe at biomass production.