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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Research Project #431574

Research Project: Reducing the Environmental Footprint from Agricultural Systems through Managing Resources and Nutrient Inputs

Location: Soil, Water & Air Resources Research

Project Number: 5030-11610-004-00-D
Project Type: In-House Appropriated

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

Objective:
Objective 1: Characterize and improve accounting of N emissions as N2O and NH3 losses from cropping systems. Subobjective 1.1: Quantify the soil and environmental factors contributing to N2O production by nitrifying and denitrifying bacteria. Subobjective 1.2: Assess the effect of cover crops on N2O production in the field. Subobjective 1.3: Assess manure injection/incorporation methods for impact on residue/surface cover, soil disturbance, and N emissions. Objective 2: Enhance process-level characterization of agrochemical emissions, fate and transport across spatial scales from micro-environments to regions. Subobjective 2.1: Determine the effect tillage practices have on agrochemical volatilization losses from agricultural fields. Subobjective 2.2: Improve measurement and modeling approaches to describe agrochemical emissions and transport from agricultural operations. Subobjective 2.3: Determine the emission flux of NH3 and other gases from cattle feedlot surfaces using flux-gradient technique. Subobjective 2.4: Compare particulate plume data measured with LiDaR to conventional model (ex. AERMOD) predictions to assess model accuracy for both near facility and downwind transport. Subobjective 2.5: Develop an improved physics-based model on the dispersion of herbicide droplets from mechanical sprayers by incorporating ambient turbulence conditions, the turbulent kinetic energy generated by the motion of the sprayer, and atmospheric stability. Objective 3: Develop strategies to manage the effects of manure properties and air flow on NH3 emissions. Subobjective 3.1: Manipulate swine diet formulations to improve N utilization, and reduce N excretion and NH3 emission along with other gaseous emission into the environment. Subobjective 3.2: Evaluate and develop ventilation practices for reducing NH3 and other air quality emissions.

Approach:
This project will focus on knowledge gaps that exist in the loss of N and agrochemicals from cropping and animal systems. Three approaches will be pursued for addressing knowledge gaps: 1) quantify soil and environmental factors contributing to N2O and NH3 emissions in animal production and field cropping systems; 2) determine soil properties that drive volatile loss and transport of agrochemicals and N compounds, and 3) determine effectiveness of N control strategies for reducing NH3 emissions. In cropping systems, there are large gaps in our understanding of the N budget in soil including both mechanisms and magnitude of losses through emissions. Laboratory studies on N2O emissions will use stable isotopes to quantify both the effect of temperature and kinetics of denitrification under varying NH3 concentrations. Field studies using chambers will be used to quantify N2O emission for a range of soil and nitrogen management strategies. Assessing the effect residue/surface cover and soil disturbance have on N loss from manure application in cropping systems will be conducted during late fall and early spring. Whole field emissions loss of N will be quantified using both an open path laser system coupled with inverse dispersion modeling for NH3 and eddy covariance with a quantum cascade laser system for N2O emissions. Quantifying the transport parameters controlling volatile losses of pesticides from cropping systems based on tillage practices will use eddy covariance micrometeorology techniques to determine turbulent flux from whole fields. The relaxed eddy accumulation technique will be used to provide more accurate eddy diffusivities for pesticide vapor transport to improve agrochemical volatilization flux estimates. In addition, LiDaR will be used to develop dispersion models for droplets from mechanical sprayers for physics-based models on the loss of agrochemicals from fields due to spray drift. Quantifying the transport parameters controlling volatile losses of N compounds and particulates from animal production systems will involve LiDaR- to measure plume dynamics and produce a remote-sensing approach to quantify emissions and compare these results to conventional modeling approaches. In animal production systems, NH3 is the dominant form of N emissions, but gaps exist in effective N control/mitigation strategies that reduce N emissions. Reducing NH3 emissions from animal production will focus on improving N utilization in animal diets by use of feed additives and improving grind size of feed particles. Ventilation practices will be evaluating and optimized for reducing NH3 emissions. Knowledge gained through this research will provide producers and regulatory agencies scientific data to improve sustainability of agricultural production facilities in U.S. farming systems.