Location: Soil Management and Sugarbeet ResearchTitle: Still gaining: Long-term benefits of conservation bioenergy practices
Submitted to: Soil and Water Conservation Society International Annual Conference
Publication Type: Abstract Only
Publication Acceptance Date: 3/16/2022
Publication Date: N/A
Interpretive Summary: No Interpretive Summary is required for this Abstract Only. JLB.
Technical Abstract: Conservation agricultural management practices and perennial bioenergy crop production can increase soil organic C (SOC) stocks on marginal soils. Co-benefits often associated with increased SOC are positive effects on water and nutrient retention, soil microbial biomass (SMB) and diversity and soil structure, resulting in better soil quality. However, tracking changes over time is necessary to quantify these benefits, and identify metrics that reflect meaningful long-term soil change. We measured a variety of surface soil (0-30cm) properties and soil quality indicators including SOC, aggregate stability, SMB-C, bulk density (BD), soil volumetric water content ('v) at field capacity (FC) and wilting point (WP), and available water (FC – WP) over 16-year bioenergy study. Switchgrass (Panicum virgatum L.), and no-tilled corn (NT-C, Zea mays L.) were established under N fertilizer (0, 60, 120, and 180 kg N ha-1) and harvest management treatments on a marginal soil in the western U.S. Corn Belt. Switchgrass, with large, deep root biomass, has the potential for long-term soil C storage and soils continue to linearly accrue SOC. Soil quality indicators SOC, microbial biomass, and aggregation showed greater increases under switchgrass and increased over time. Available water increased with increasing SOC content, but the effect was small and unlikely meaningful for plant growth. Conservation management impacts on water capture and infiltration may be much larger than the water storage. Our results suggest that perennial systems need long-term measurements to accurately quantify bioenergy impacts and evaluate model predictions.