Location: Soil, Water & Air Resources Research
Project Number: 5030-12210-004-000-D
Project Type: In-House Appropriated
Start Date: Oct 5, 2021
End Date: Oct 4, 2026
Objective 1: Develop improved crop practices based on carbon management that can be used to enhance soil physical properties in agricultural production systems, including better soil drainage and degradation of a subsoil fragipan. Subobjective 1.A: Investigate decadal impacts of artificial drainage on soil health. Subobjective 1.B: Evaluate annual ryegrass cover crops for improving seasonal soil water dynamics in fragipan soils. Subobjective 1.C: Determine the chemical composition of fragipans at varying stages of degradation by ryegrass or humic product application. Subobjective 1.D: Determine the effects of a humic product on the chemical speciation and quantities of root exudates released by ryegrass in a hydroponic system. Objective 2: Establish the benefits of plant biostimulants, including humic products, to enhance plant growth and improve soil properties, and identify their mechanistic effects on plant physiological processes to develop more resilient agroecosystems. Subobjective 2.A: Identify plant physiological processes that respond to humic product application for multiple plant types in diverse field settings and determine environmental influences on the plant responses. Subobjective 2.B: Evaluate humic product impacts on soil physical properties. Objective 3: Determine the responses of soil organic matter biochemistry to crop management practices in order to establish mechanistic interrelationships among soil carbon cycling, physical properties, and nutrient availability, and therefore develop improved management practices to optimize cropping system sustainability.
At multiple Corn Belt sites, historical changes in soil carbon (C) stocks and associated soil properties will be measured under current soil drainage practices, including proposed future practices, to help drainage management adapt to changing precipitation patterns in the Midwest. In the southern Corn Belt, existing studies of annual ryegrass and humic products as management options for degrading a hardened subsoil fragipan will be expanded. Their benefits will be measured for improving seasonal water relations and extending rooting depth through fragipan degradation at multiple sites. Existing field investigations of humic products as a crop amendment will be expanded by identifying their seasonal effects on plant carbohydrate production and plant hormone fluxes, as potential mechanistic explanations for the improved grain yield that was demonstrated previously in corn-soybean rotations. The commonality of these plant process responses to humic products will be established by expanding the scope of field sites to include natural grasslands, wheat, and potentially additional crops in other U.S. regions. To distinguish the relative contributions of plant vs. microbial materials to soil C sequestration, the concentrations of plant and microbial bio-marker compounds will be measured in labile fractions of soil organic matter for field treatments in two wheat-based and corn-based agroecosystems where soil C has been sequestered. Project results will provide critical information needed to guide the use of C amendments and other crop management practices for promoting soil C accumulation, enhancing other soil properties, and increasing crop performance, primarily for corn-based Midwestern cropping systems.