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United States Department of Agriculture

Agricultural Research Service

Research Project: Enhancing Production and Ecosystem Services of Horticultural and Agricultural Systems in the Southeastern United States

Location: Soil Dynamics Research

Project Number: 6010-11120-008-00-D
Project Type: In-House Appropriated

Start Date: Sep 22, 2016
End Date: Sep 21, 2021

Objective 1: Assess above- and belowground responses of pastures to elevated CO2 and their ability to help mitigate climate change via sequestration of CO2. Sub-Objective 1a: Process and publish on biomass (above- and belowground) and soil physicochemical data, inclusive of soil C and N dynamics, from the 10-year CO2/N bahaigrass pasture study. Sub-Objective 1b: Plant a Southeastern bermudagrass pasture to determine the effects of atmospheric CO2 level and N management on above- and belowground responses of the plant/soil system. Sub-Objective 1c: Process and publish on soil flux of trace gases (CO2, N2O, CH4) from the 10-year CO2/N bahaigrass pasture study. Sub-Objective 1d: Plant a Southeastern bermudagrass pasture to determine the effects of atmospheric CO2 level and N management on soil flux of trace gases (CO2, N2O, CH4). Sub-Objective 1e: Determine the effects of elevated CO2 on efficacy of herbicidal control of weeds problematic in Southeastern agricultural systems. Sub-Objective 1f: Work on effects of elevated CO2 on growth and efficacy of herbicidal control of herbicide resistant weed populations. Objective 2: Manipulate fertilizers, soil amendments such as biochar, and irrigation in ornamental horticultural systems to reduce GHG emission and increase C sequestration. Sub-Objective 2a: Identify best management practices (e.g., fertilizer placement, irrigation method) that reduce GHG emissions while optimizing growth for various horticulture crops. Sub-Objective 2b: Determine the longevity of carbon in horticultural growth media (e.g., pine bark, clean chip residual, whole tree) following placement in the landscape. Sub-Objective 2c: Investigate the effects of biochar in growth media (pine bark) on growth, nutrient retention, and GHG emissions in various ornamental horticultural crops. Objective 3: Develop improved methods to utilize organic waste and soil amendments for soil and crop benefits while minimizing environmental degradation. Sub-Objective 3a: Determine the rate of Flue Gas Desulfurization (FGD) gypsum needed to increase corn yield and reduce soluble P concentration in soil. Sub-Objective 3b: Determine the rate of FGD gypsum needed to reduce P losses in runoff under no-till and conventional tillage. Sub-Objective 3c: Determine the influence of poultry litter as a nutrient source for winter wheat and canola, and its residual effects on succeeding soybean and wheat crops. Sub-Objective 3d: Evaluate the influence of poultry litter vs. inorganic fertilizer on crop production under different management practices. Sub-Objective 3e: Develop a four-band implement for subsurface band application of pelletized poultry litter, poultry litter, and similar solid manures. The implement will use pneumatic conveying or a similar method to convey the product. Sub-Objective 3f: Evaluate effectiveness of subsurface application of poultry litter for row crop production.

A long-term Southeastern bahaigrass pasture study will be terminated and a bermudagrass pasture study will be initiated. Both systems are exposed to current and projected levels of atmospheric CO2 and either managed (N added) or unmanaged (no N). Carbon flux to plants (biomass growth, allocation, and quality) and soil will be determined with supporting data on soil physicochemical properties. Emphasis will be given to measuring soil C and N dynamics and C storage, root growth, water quality, and GHG (CO2, N2O, and CH4) flux from soil. Using the same CO2 levels, container studies on weeds important to the southeastern U.S. (including those resistant to herbicides) will evaluate herbicide efficacy, re-growth, biomass, and tissue quality. In addition, research will evaluate production practices (in terms of such factors as fertilizer placement, growth media, and irrigation) to identify best management practices which ensure productivity, minimize GHG emissions, and maximize belowground C storage in the landscape for various horticulture crops. Other work will examine how the application of organic waste to soil can improve soil conditions via C addition and provide nutrients needed for crop production. Poultry litter may be a viable fertilizer option for crop producers in the Southeastern U.S. given the large amounts of manure generated by the poultry industry and the rising costs of inorganic fertilizers. However, improper application of animal manures in agriculture can contribute to environmental degradation such as increased hypoxia, eutrophication of surface waters, human health problems, and greenhouse gas emissions. Due to these environmental concerns, field and laboratory studies will be established to develop improved methods to utilize waste products for soil and crop benefits while minimizing environmental degradation. In addition, interactions of manure with tillage and cropping systems is not well understood. Thus, the environmental impact of poultry litter addition to soil must be quantified and improved management techniques for application needs to be developed for sustainable use in agriculture. Studies will be initiated to determine long term effects of poultry litter on plant yields, and soil physicochemical properties (including C storage) under various tillage and cropping systems. Further, different poultry litter application practices, such as subsurface banding, will be evaluated to determine their impact on nutrient loss and greenhouse gas emissions. Soil amendments (e.g., gypsum) will be evaluated to determine the impact on plant responses and the potential to reduce phosphorus (P) loss in runoff. Information acquired in the course of this project will be useful for developing agricultural practices using poultry litter as a nutrient source for environmentally sustainable plant production. Integrating data from these studies will aid understanding on how to adjust future agronomic management practices to sustain productivity, while aiding mitigation of global change via increasing soil C sequestration and reducing greenhouse gas emissions.

Last Modified: 09/24/2017
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