1a. Objectives (from AD-416)
Evaluate the long-term effect of soil organic carbon (SOC) on soil quality: 1)To determine the amount and types of carbon accrued in long-term field plots; 2)To evaluate the effects of tillage practice, winter cover cropping, compost application, soil depth and soil aggregate size fraction on total SOC and SOC constituent contents; 3)To relate total SOC and SOC constituent contents with soil structural stability and erodibility; 4)To determine total SOC content level and constituents most effective at increasing soil stability and reducing soil erodibility; and 5)To identify agronomic practices that effectively increase soil stability and decrease erodibility.
1b. Approach (from AD-416)
Soil quality will be evaluated in university controlled long-term piedmont and coastal field plots that have treatments of no-tillage, no-tillage with winter cover and compost, disk tillage, and disk tillage with winter cover and compost. In each treatment, SOC will be analyzed for particulate carbon, labile carbon, microbial biomass, total soil carbohydrates, and glomalin. SOC components will be related to mineralization, respiration, and aggregate stability. Testing for aggregate stability include wet sieving, dry sieving, and rainfall simulation of selected aggregate sizes analyzing runoff and splash.
3. Progress Report
This research relates to the inhouse objectives: Improve soil structure and reduce soil strength to improve crop productivity and environmental quality. Improve Coastal Plain soil physical properties that increase infiltration of rainfall/irrigation and increase plant available water content using conservation tillage and reduced compaction. Develop structure in sandy Coastal Plain soils to increase plant-available water holding capacities, reduce penetration resistance, sequester carbon, and bind excess phosphorous and trace elements. Increase soil organic matter contents to improve soil physical/chemical properties in highly-weathered sandy Coastal Plain soils using cover crops, biochar, and green manures. A proposal was written with researchers at NC A&T State University to investigate the effects of cover crops, compost application, and tillage management on soil erosion, aggregation, and organic matter. Researchers are recipients of a 2010 NIFA grant from the 1890 Institution Capacity Building Grants Program “Food and agricultural byproduct-based biochars for enhanced soil fertility and long-term carbon sequestration” (Proposal 2010-02371). The project was approved for funding on 1 July 2010 and project initiation will be forthcoming. This funded proposal will develop biochar, a charcoal-like material, by pyrolyzing crop and food-waste feed-stocks under controlled conditions to design amendments for selected Coastal Plain and Piedmont soils. Relationships between the biochar and production of greenhouse gases (GHG) will be examined to insure that the biochars do not accelerate GHG production. It is anticipated that specialized biochars will improve Coastal Plain and Piedmont soil quality while also increasing soil carbon sequestration. Project monitoring includes e-mails, phone calls, and face-to-face meetings.