2012 Annual Report
1a.Objectives (from AD-416):
Objective 1: Quantify water and nitrate fluxes out the bottom of the rootzone into tile drains. This contributes to monitoring of water and N flux and storage, for “footprints”. Objective 2: Develop science-based knowledge that addresses climate mitigation and adaptation, informs policy development, and guides on-farm, watershed level, and public decision making in corn-based systems, using both conventional and organic production practice.
1b.Approach (from AD-416):
1. Our comparison is Drainage Water Management (DWM) vs. conventional “free” drainage. We will be using a farmer cooperator site we have already established, building on regional work started in the recent Conservation Innovation Grant that just ended. Treatments: DWM vs. free drainage. Rotation: corn-soybean-wheat, only one phase each year. Tillage system: all sites are some form of conventional till, appropriate for that area. Treatment areas are large production fields or portions of fields. DWM reduces drainflow and nitrate loads from tile drained fields. It may also in some years, increase crop yield. 2. Our approach is to quantify and compare the water, carbon, and nitrogen balances between no-till based conventional practice (commercial fertilizer and pesticides are used) and organic practice (no chemical amendments) corn-soybean-wheat rotations on six small instrumented watersheds at the OARDC research facility in Coshocton County, OH. OARDC has agreed to provide field facilities, equipment, and support personnel to conduct the research plan through a Research Support Agreement with the Soil Drainage Research Unit. Analysis and interpretation of the data will be the responsibility of ARS scientists. Each phase of both rotations will be present every year in separate small watersheds where we will measure and account for the water, carbon and nitrogen. Precipitation, runoff, soil moisture content, and ET will be continuously monitored. Annual soil and biomass samples will be analyzed to quantify form and fate of carbon and nitrogen in the system. Runoff samples will also be analyzed to determine carbon and nitrogen migration from the system. Nitrogen and water use efficiency will be determined for both the conventional and organic rotation systems.
Research activity conducted within this Reimbursable Agreement directly contributes to Sub-Objective 1a of the parent project: Develop subsurface drainage water management system design and operational criteria that optimize environmental protection and crop production; and to Sub-Objective 2a of the parent project: Evaluate no-till, soil amendment, and cover crop practices as compared to conventional management practices for improving crop yield and soil/water quality in intermittently wet soils.
For objective 1, precipitation, drain discharge volume, water table level, and soil water content were all monitored continuously for both drainage water management treatment zones. Agronomic production inputs and crop yield were recorded. Drainage water samples were taken periodically and analyzed for carbon (C), nitrogen (N), and phosphorous (P). Soil samples and crop seed and stover samples were obtained and analyzed for C and N. Parameter values have been entered into the Climate and Corn-Based Cropping Systems Coordinated Agricultural Project CSCAP database.
For objective 2, pursuant to the closure of the ARS North Appalachian Experimental Watershed (NAEW) location effective 9/30/2011, Project # 3605-13000-004-11R budget and management were transferred to the Soil Drainage Research Unit Columbus to fulfill the agreement with Iowa State University under the project titled: CLIMATE CHANGE, MITIGATION, AND ADAPTATION IN CORN-BASED CROPPING SYSTEMS. Collaboration has been established with the Ohio State University, Ohio Agriculture Research and Development Center (OARDC) to carry out the day-to-day data field operations and sample collection activities; data collection, processing, and management activities; and purchase of supplies, materials, and some analytical sample processing. Data collection continued on seven watersheds and seven lysimeters, three rain gauges, and a weather station. Runoff and lysimeter water samples were analyzed by the ARS lab in Columbus, Ohio. Soil and plant samples were analyzed for C and N at the STAR lab at OARDC. All of the project treatment, sampling, and data management activities are current although the weather conditions and weed pressure have created the need for changes in the cover crops related to the organic farming treatment. In an effort to improve weed control, the cover crop has been changed from red clover inter-seeded in the wheat phase of the rotation to use of various combinations of annual rye grass, cowpea, Austrian winter pea, and oil seed radish depending on the phase of the rotation present in each watershed. These crops provide greater competition for weeds because of their rapid early growth which causes shading of emerging weeds as well as their allelopathic attributes which suppress weed seed germination.