Location: Soil, Water & Air Resources Research
Project Number: 5030-11610-006-000-D
Project Type: In-House Appropriated
Start Date: Sep 14, 2021
End Date: Sep 13, 2026
Objective:
Objective 1: Develop new methods and improve the characterization of carbon, nitrogen and water cycles and agrochemical dynamics to improve management opportunities for better productivity and reduced environmental impact.
Subobjective 1.1: Evaluate and compare management system influences on ET, CO2 exchange, surface energy balance partitioning and N2O emissions as a function of conventional and cover crop tillage practices.
Subobjective 1.2: Evaluate effect of drainage depth and spacing on N2O emissions.
Subobjective 1.3: Develop an improved measurement technique to quantify volatilization and atmospheric transport of agrochemicals necessary to develop and evaluate agrochemical management and remediation strategies.
Objective 2: Improve understanding of nutrient partitioning and flows from animal production to field application of manure to reduce gaps in emission inventories and improve mitigation techniques.
Subobjective 2.1: Determine NH3 and H2S emissions from swine finishing barn and manure storage based on feed inputs.
Subobjective 2.2: Assess manure injection/incorporation methods for impact on residue/surface cover, soil disturbance, and NH3 emissions.
Subobjective 2.3: Develop improved techniques for quantifying ammonia deposition near livestock production sites.
Objective 3: Identify drivers of soil and plant associated microbial community structure and function to improve soil health, nutrient use efficiency, and system resilience.
Subobjective 3.1: Test cropping system influence on soil and plant associated microbial communities.
Approach:
This project will focus on knowledge gaps that remain in nutrient cycling, water use efficiency, and fate of resource inputs for cropping-livestock systems including cropping systems with highly structured canopies. Three approaches will be pursued for addressing knowledge gaps: 1) Long-term agriculture research (LTAR) networks to evaluate tillage, cover-crop, and fertilizer management influence on surface energy partitioning, water use efficiency, soil health and greenhouse gas emissions; 2) Turbulent transport mechanisms will be determined, including deposition and management practices that reduce the loss of agrochemicals from cropping systems; and 3) The partitioning of nutrients in livestock systems will be determined to evaluate management practices that reduce nutrient emissions and deposition. Field studies at LTAR network sites using eddy covariance towers will quantify evapotranspiration, carbon dioxide exchange and surface energy partitioning from reduced tillage practices with chamber studies at LTAR sites being used to quantify nitrous oxide (N2O) emissions from a range of soil and nitrogen management strategies. In other field studies, eddy covariance towers will be used to quantify water use efficiency through variable irrigation scheduling in vineyards and chamber studies used to quantify N2O emissions through intensified drainage practices. The transport parameters controlling volatile losses of agrochemicals from cropping systems based on tillage practices will be quantified using eddy covariance micrometeorology techniques to determine turbulent flux from whole fields. The relaxed eddy accumulation technique will be used to provide accurate eddy diffusivities for agrochemical vapor transport to improve agrochemical volatilization flux estimates. Riparian buffer zones will be used to quantify the fraction of agrochemicals captured by vegetative buffers to the fraction of agrochemicals volatilized. Open path ammonia (NH3) lasers will be used to quantify NH3 emissions using both barn ventilation and micrometeorology inverse dispersion modeling techniques. The partitioning of nutrients between animal, manure, and gas emissions will be quantified based on nutrient inputs (feed, animals, and residue manure) and nutrient outputs (live and dead animals, manure, and gas emissions of nitrogen (N) and sulfur (S) compounds from barns). Open path methane (CH4) and NH3 lasers and an array of NH3 passive samplers along a transect from an animal feeding operation will quantify NH3 dry deposition using both a tracer gas technique and a bidirectional NH3 flux modeling technique. The quantification of soil extracellular polymeric substances and soil aggregate stability coupled with microbial genome sequencing analysis will be used to evaluate tillage and cover-crop impact on soil health. Knowledge gained through this research will provide producers and regulatory agencies scientific data to improve the sustainability of agricultural production facilities in U.S. farming systems.
