EXAMINING SOIL-PROFILE C POOLS, C SEQUESTRATION, AND SOIL HEALTH UNDER EARLY- AND LATE-TERMINATED COVER CROPS IN RAINFED AND IRRIGATED NO-TILL CONTINUOUS CORN IN THE LONG TERM

Long-Term Goal The long-term goal of this project is to promote C maintenance or sequestration and improvement in the health of agricultural soils by using improved cover crop (CC) management practices in rainfed and irrigated no-till systems in the Corn Belt and western Corn Belt in particular.Specific Objectives Evaluate the long-term (10- to 14-yr) impacts of early- and late-terminated CCs on soil-profile C sequestration and C pools in rainfed and irrigated no-till continuous corn to at least 1 m soil depth in the western Corn Belt.Assess the long-term (10- to 14-yr) impacts of early- and late-terminated CCs on soil health indicators (physical, chemical, and biological properties) at different soil depth intervals to at least 1 m depth in rainfed and irrigated no-till continuous corn in the western Corn Belt.Use process-based models to extrapolate the effects of CCs on soil C sequestration and soil properties to regional scales.HypothesesEarly- and late-terminated CCs will sequester C and increase C pools in the whole soil profile relative to no CCs, but late-terminated CCs will accumulate more soil C than early-terminated CCs due to increased CC biomass production.Early- and late-terminated CCs will enhance no-till potential to improve soil health not only in the surface (< 30 cm) but also in the subsoil (> 30 to 100 cm).Process-based models can satisfactorily estimate soil C stocks and C pools under different CC management practices (early vs. late) on regional scales.