2007 Annual Report
1a.Objectives (from AD-416)
Modify existing farming systems and develop new production systems that, through use of conservation tillage and intensive cropping practices, improve profitability and reduce economic risks by enhancing carbon storage, plant available water, and soil productivity and quality.
1b.Approach (from AD-416)
Research challenges include developing integrated conservation systems for livestock-row crop production, integrating residue management and other soil management practices to increase plant available water, improving nutrient use efficiencies of organic nutrient sources, and developing rapid soil quality assessment tools for use in management decisions and evaluating the economics of their use. Three replicated field studies will be conducted on Alabama Agricultural Experiment Station (AAES) facilities: (1) Site-specific agriculture and landscape dynamics of soil quality as affected by management, (2) Tillage and rotation as factors for changing soil quality of a Decatur silt loam in the Tennessee Valley, and (3) Tillage requirements for winter-annual grazing rotations. The research task is not complete until the information is effectively delivered to the customers and stakeholders; consequently, a technical information specialist will be dedicated to transferring the information and technology to action agencies and the general public.
This report serves to document research conducted under a Specific Cooperative Research Agreement between ARS and Auburn University. Additional details of research can be found in the report for the in-house project 6420-12610-003-00D, "Conservation Systems Research for Improving Environmental Quality and Producer Profitability." Auburn University, in cooperation with USDA-ARS, is conducting a joint test evaluating the effects of landscape variability and crop management, crop productivity, and soil quality. This test is being conducted at E.V. Smith Research and Extension Center in South Central Alabama on a 20-ac site. The site consists of typical Coastal Plain soils on rolling topography with significant terrain variability. The site has 6-replications of four crop management systems (conventional and conservation tillage with/without dairy manure) traversing the field as strips in a corn – cotton rotation; both phases of the cropping system are in place each year. Data being collected includes yield mapping, soil survey data, electrical conductivity, and terrain attributes. Different techniques for grouping the soil and terrain variability are currently being evaluated. The goal of this study is to gain a more through understanding of the interaction of crop management and soil landscapes, and the development of techniques for developing management zones for cost-effective site-specific management. Simulation modeling was used to evaluate short change soil organic carbon (SOC) dynamics when transitioning from convention al to conservation crop management systems. The rationale was that if calibrated models can effectively simulate SOC dynamics, assessment of site productivity (since SOC is highly correlated with crop yields in our region) and C sequestration over time could be developed. An automatic parameter optimization procedure was used to calibrate the Environmental Policy Integrated Climate (EPIC) model against results from the site-specific experiment at the E.V. Smith Research and Extension Center in Shorter, AL. Model performance in predicting corn and cotton yields and soil organic carbon (SOC) dynamics was evaluated on different landscapes of a Coastal Plain soil during the initial adoption of conservation tillage (5 years). Simulated yield explained 88% of measured yield variation, with greatest disagreement between measurements and simulations at the sideslope position, and the least disagreement in the drainageway. With enhance models, we concluded that EPIC could be a valuable tool for simulating field-scale SOC dynamics affected by short-term management decisions. In addition, as part of this agreement, a15-acre partially irrigated cotton field in the Tennessee Valley region of North Alabama was infested with reniform nematodes for future reniform tests. Several experiments will be started in Fall of 2007 to determine appropriate soil management to reduce the effects of nematodes on cotton production in conservation tillage systems. The ADODR has monitored activities via email correspondence, teleconferences, and site visits.