High groundwater nitrate is a serious problem in certain areas across Nebraska. The risk for nitrogen leaching below the root zone is greatest beneath intensively irrigated sandy, well-drained soils. Few, if any, cost-effective alternatives are available to producers for controlling nitrate losses in highly vulnerable, irrigated soils. This program will demonstrate the efficacy of subsoil wood carbon injection for improving groundwater quality in areas vulnerable to nitrate leaching by forming a subsoil bioreactor layer. Locally harvested and ground woodchips will be injected at or below the crop root zone using a modified subsoil plow outfitted with a variable-speed auger hopper. This subsoil bioreactor will improve water retention in sandy soils and provide carbon to microorganisms that will intercept nitrate lost below the root zone over many growing seasons. This management practice can be scaled up and will provide a beneficial use for waste wood products currently burned or buried on Nebraska farmland, with potential benefits for enhancing carbon sequestration, improving soil health through increased carbon content and increasing resilience to erratic weather conditions.