Location: Soil, Water & Air Resources Research
2018 Annual Report
Objectives
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.
Progress Report
Objective 1: Experiments were conducted to quantify nitrous oxide production in response to temperature, soil water content, and nitrate concentration. It was found that the temperature response of nitrous oxide production from water-saturated soil was greater under aerobic conditions than under anaerobic conditions. Additional experiments will determine the extent of this phenomenon under different N regimes.
Nitrous oxide emissions were measured throughout the year, and the temporal variability analyzed with respect to rainfall. Similar data were summarized for previous years and the response of peak nitrous oxide emission events were characterized. A linear relationship was observed between the contribution of peak nitrous oxide emission to total annual nitrous oxide emission and the amount of rainfall that occurred after nitrogen fertilization.
Field method validation for N loss during application of manure was conducted for two different sites. Based on open path NH3 laser data, the loss of NH3 was significantly higher than literature estimates of 3%. NH3 volatilization also occurred over a significantly longer duration than previously estimated. Field sampling protocols were modified to captured longer sampling periods and dynamic wind flow patterns. Wind tunnel (WT) use was challenging due to the time it took for set up compared to laser systems and WTs were ineffective when field winds were greater than 3 m/s (6.7 mph). Portability of WTs also limited their deployment at remote field sites. Challenges in NH3 monitoring delayed testing of a N2O analyzer so instrument validation was delayed for another year.
Objective 2: The Relaxed Eddy Accumulation (REA) instrument requires the ability to sample pesticides at concentrations and flow rates that are commensurate with high precision fast acting solenoid valves. Previous pesticide sampling flow rates were approximately five-fold higher than the fast-acting solenoid valves. Pesticide analysis and sampling protocol were changed so that REA instrument flow rates and fast acting solenoid values were linked. However, additional testing was required for a second season as the sampling protocol had to be further refined to accommodate the newer fast acting solenoid valves. This was a needed development, but set back the project another 12 months.
Nighttime periods where atmospheric conditions are stable present challenges to properly estimate herbicide volatilization losses. Accessing the 15 years of a pesticide volatilization database we partitioned daytime (unstable) and nighttime (stable conditions) periods for herbicide and local surface parameters and began assessing data quality to select the most robust years for evaluating pesticide emissions. Four years have been identified as ideal candidates for developing model expressions of volatilization losses under stable nighttime conditions.
Characterizing the upwind and downwind air flow conditions of an animal feeding operation (AFO) is essential to predicting particulate emissions. High frequency sonic anemometer data have been processed to determine mean 3-dimensional wind flow directions. Standard deviations of these means were computed and the turbulent covariance’s that carry particulates. More analysis is ongoing to compare these parameters under different stability regimes, which can significantly impact the distribution (vertically and horizontally) of particulate emissions.
Spray drift dispersion during application was monitored for 1.5 days during a pilot study to determine the vertical and horizontal range of spray droplets. A large agrochemical spray rig presented a considerable bluff body that generates significant turbulence during application. The strength of turbulence was measured and shown to create a lofting vortex that sent droplets vertically 10’s of meters and nearly 100 meters horizontally. This pilot study confirmed the need for a wider range of conditions to include stable and unstable conditions that establish drift loss potentials based on local meteorological conditions and the rate of speed of the spray rig. A second more intensive measurement campaign is planned for the fall.
Objective 3: A study was conducted to determine the effectiveness of wet scrubber systems in swine finishing operations to control emissions of ammonia, particulate matter (PM), and odor. A commercial 2500 head swine finishing operation with a wet scrubber system was monitored for the control of air and PM emissions. The facility uses air filters to control incoming air and operates as a negative pressure system that uses the wet scrubber on fan outlets. Air from the sidewall baffles were directed to the wet scrubber. Air entering and exiting the wet scrubber system were monitored for ammonia, PM, and volatile organic compounds. Preliminary analysis of the air exiting the building showed concentrations of NH3 reduced by 20-35%, odor by 30-60%, and dust by 80-90%. Additional research is being conducted to optimize the dosing solution of the wet scrubber system.
Midwest Climate Hub: During winter and spring 2018, the Midwest Climate Hub (MCH) continued outreach to specialty crop producers (with Midwest Regional Climate Center, MRCC) at 5 conferences in the Midwest Region (total no. of participants ~ 1000 ). Engagement centered on climate impacts being/have been experienced by producers, (specifically drought), climate tools currently being used (i.e. rain gauges, drought impact reporter, Midwest Climate Hub tools and resources, etc.), and how, if any, adaptations have been implemented in producers’ management practices to mitigate climate/drought impacts. Approximately 150 producers were actively engaged by Midwest Regional Climate Center and Midwest Climate Hub staff, most of which were informed of National Drought Monitor Center’s mission and the U.S. Drought Monitor.
• 56 questionnaires were filled out by producers from six states (Michigan, Indiana, Wisconsin, Illinois, Minnesota, and Iowa). Most of the respondents were fruit and vegetable crop producers, with some also raising livestock and traditional row crops. Two-thirds of respondents farmed fewer than 100 acres, and another quarter farmed between 100-500 acres.
• About 60% of respondents had experienced significant drought over the past five years, but their biggest immediate concerns were fluctuations in spring temperatures and variable freeze/frost conditions.
• Only 39% said they used the U.S. Drought Monitor (lower than reported among larger corn and soybeans growers in the same region). Nearly 80% of respondents would be willing or maybe) to report drought impacts to inform the U.S. Drought Monitor. These findings indicate potential for working with specialty crop producers to better meet their needs for drought monitoring information, and engage them in the process.
In cooperation with ARS Air Quality National Program, the Midwest Climate Hub coordinated purchase of instrumentation to help create a regional inversion monitoring system in cooperation with the Midwest Mesonet Consortium. Installation of equipment has created the first regional effort at inversion monitoring to help reduce potential drift issues. Planning for a regional science workshop on chemical, ammonia and odor drift issues related to inversions is ongoing to help connect drift and monitoring communities to help reduce drift issues. We have also leveraged resources from NRCS for creating a regional web presence for the inversions, to develop climatologies of inversions and to help support the regional meeting.
As of July 2018 over 75% of the instrumentation has been installed and is reporting information in six states. Four states have already developed systems to report inversion information on state mesonet web sites (Missouri, Illinois, Kentucky, and Michigan). The partnership among USDA, the Midwest Regional Climate Center and seven state-run monitoring networks has created the first regional set of inversion monitoring anywhere in the country. Kentucky has matched the installation and added more stations using internal dollars. South Dakota has added stations to match the Midwest efforts. Monsanto’s Climate Corporation is using the inversion information to verify inversion forecast conditions from an application developed to serve in their on-farm management software.
The Midwest Climate Hub and partners has developed a list of 25 important indicators for agriculture, which can be measured and repeated to continue tracking information. The indicators are being refined and written for a final report and climate hub use. The effort expands on research developed by Hatfield et al. to be more comprehensive in indicators and develop some possible effort for ongoing assessment of climate change issues. Each of the indicators will have a stand-alone publication which can be published on hub web sites for individual download. The total set will be a more comprehensive report on ag-climate change indicators.
Accomplishments
1. Rising global temperatures (Global Warming) can influence the activities of soil bacteria that produce greenhouse gasses. ARS researchers at Ames, Iowa conducted experiments to quantify the activities of greenhouse gas producing bacteria under different temperature regimes. Greater temperature sensitivity of nitrous oxide production under aerobic conditions strongly suggests a positive temperature feedback phenomenon whereby increasing temperature increases both the denitrification process and other heterotrophic microbial activity. This overall enhanced heterotrophic activity increases the oxygen consumption of the microbial community increasing the anaerobic volume of a soil leading to greater overall denitrification. Implications of this result indicate a positive feedback between increasing soil temperatures and increased nitrous oxide emissions. This information will be useful to scientists interested in predicting the future increases in atmospheric levels of greenhouse gasses.
2. Accurate quantification of the greenhouse gas nitrous oxide from agricultural systems is difficult and expensive due to the high temporal variability associated with the microbial processes that produce this gas. ARS researchers at Ames, Iowa, measured and characterized the high temporal variability of soil nitrous oxide emissions that are characterized by episodic events caused by rainfall. This work quantifies the response of nitrous oxide flux to rainfall events after nitrogen fertilization. Reports of increased precipitation intensity due to climate change will exacerbate this effect unless modifications in N fertilizer management (form, timing, and placement) can mitigate this effect and reduce annual nitrous oxide emissions. The information of this study will aid in the development of agricultural management systems to mitigate soil greenhouse gas emissions.
3. Lower ammonia and odor emissions through diet formulation. The use of growth-promoting ionophores in livestock diets is thought to improve feed efficiency and thereby reduce emissions of NH3. ARS researchers in Ames, Iowa, conducted a swine feeding trial to test the effect ionophore supplementation has on manure composition and gas emissions in finishing pig diets. Data from this study showed that neither NH3 nor odor compound emissions were impacted by ionophore supplementation. The use of ionophores in swine diets for finishing pigs had little to no benefit in lowering emissions of NH3 and odor compounds.
Review Publications
Davis, M.P., Groh, T.A., Parkin, T.B., Williams, R.J., Isenhart, T.M., Hofmockel, K.H. 2018. Portable automation of static chamber sample collection for quantifying soil gas flux. Journal of Environmental Quality. 47(2):270-275. https://doi.org/10.2134/jeq2017.10.0387.
Kerr, B.J., Trabue, S.L., van Weelden, M., Andersen, D., Pepple, L. 2018. Impact of narasin on manure composition and microbial ecology, and gas emissions from finishing pigs fed either a corn-soybean meal or a corn-soybean meal-dried distillers grains with solubles diets. Journal of Animal Science. 96:1317-1329. https://doi.org/10.1093/jas/sky053.
Moore Jr., P.A., Li, H., Burns, R., Miles, D.M., Maguire, R., Ogejo, J., Reiter, M., Buser, M., Trabue, S.L. 2018. Development of the ARS air scrubber: A device for reducing ammonia, dust and odor in exhaust air from animal rearing facilities. Frontiers in Sustainable Food Systems. 2:1-10.
Gillette, K.L., Malone, R.W., Kaspar, T.C., Ma, L., Parkin, T.B., Jaynes, D.B., Fang, Q.X., Hatfield, J.L., Feyereisen, G.W., Kersebaum, K.C. 2018. N loss to drain flow and N2O emissions from a corn-soybean rotation with winter rye. Science of the Total Environment. 618:982-997. https://doi.org/10.1016/j.scitotenv.2017.09.054.
Colliander, A., Jackson, T.J., Chan, S., O'Neill, P., Bindlish, R., Cosh, M.H., Caldwell, T., Walker, J., Berg, A., McNairn, H., Thibeault, M., Martinez-Fernandez, J., Jensen, K., Asanuma, J., Seyfried, M.S., Bosch, D.D., Starks, P., Holifield Collins, C.D., Prueger, J.H., Su, Z., Lopez-Beeza, E., Yeuh, S. 2018. An assessment of the differences between spatial resolution and grid size for the SMAP enhanced soil moisture product over homogeneous sites. Remote Sensing of Environment. 207:65-70.
Reichle, R., De Lannoy, G., Liu, Q., Ardizonne, J., Colliander, A., Conaty, A., Crow, W.T., Jackson, T.J., Jones, L., Kimball, J., Koster, R., Mahanama, S., Smith, E., Berg, A., Bircher, S., Bosch, D.D., Caldwell, T., Cosh, M.H., Gonzalez-Zanora, A., Holifield Collins, C.D., Livingston, S.J., Lopez-Baeza, E., Martinez-Fernandez, J., McNairn, H., Moghaddam, M., Pacheco, A., Pellarin, T., Prueger, J.H., Rowlandson, T., Seyfried, M.S., Starks, P.J., Su, Z., Thibeault, M., Uldall, F., van der Velde, R., Walker, J., Wu, X., Zeng, Y. 2017. Assessment of the SMAP Level-4 surface and root-zone soil moisture product using in situ measurements. Journal of Hydrometeorology. 18(10):2621-2645. https://doi.org/10.1175/JHM-D-17-0063.1.
Bindlish, R., Cosh, M.H., Jackson, T.J., Koike, T., Fuiji, X., De Jeu,, R., Chan, S., Asanuma, J., Berg, A., Bosch, D.D., Caldwell, T., Holifield Collins, C.D., McNairn, H., Martinez-Fernandez, J., Prueger, J.H., Rowlandson, T., Seyfried, M.S., Starks, P.J., Su, Z., Thibeault, M., van der Velde, R., Walker, J., Coopersmith, E. 2018. GCOM-W AMSR2 soil moisture product validation using core validation sites. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 11(1):209-219. https://doi.org/10.1109/JSTARS.2017.2754293.
Chan, S., Bindlish, R., O'Neill, P., Jackson, T.J., Njoku, E., Dunbar, R., Chaubell, J., Peipmeier, J., Yueh, S., Entekhabi, D., Colliander, A., Chen, F., Cosh, M.H., Caldwell, T., Walker, J., Berg, A., McNairn, H., Thibeault, M., Martinez-Fernandez, J., Udall, F., Seyfried, M.S., Bosch, D.D., Starks, P.J., Holifield Collins, C.D., Prueger, J.H., Crow, W.T. 2018. Development and assessment of the SMAP enhanced passive soil moisture product. Remote Sensing of Environment. 204:931-941. https://doi.org/10.1016/j.rse.2017.08.025.
Andersen, D.S., Yang, F., Trabue, S.L., Kerr, B.J., Howe, A.S. 2018. Narasin as manure additive to reduce methane production from swine manure. Transactions of the ASABE. 61(3):943-953. https://doi.org/10.13031/trans.12568.
