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United States Department of Agriculture

Agricultural Research Service

Research Project: EMISSION AND DISPERSION OF AIR QUALITY CONSTITUENTS FROM AGRICULTURAL SYSTEMS
2008 Annual Report


1a.Objectives (from AD-416)
Evaluate emission and dispersion patterns to the boundary layer as a function of complex terrain and structural obstructions; Quantify the effectiveness of agricultural management to reduce ammonia and nitrous oxide emissions into the atmosphere; Identify and quantify volatile organic compounds (VOC) attached to particulates emitted from animal feeding operations and manure application on to fields. Identify and quantify amounts of endotoxins and pathogens emitted and dispersed from animal feeding operations and manure application sites.


1b.Approach (from AD-416)
Utilize a wind tunnel to conduct a series of wind flow simulations over model scale terrain and structures to determine the wind flow patterns over complex agricultural sites that include buildings. Conduct lidar measurements of particulates and water vapor coupled with turbulence measurements obtained from sonic anemometers to characterize the turbulence regime in limited fetch environments. Evaluate the potential of using open path FTIR measurements to compliment the lidar measurements in the development of improved emission and dispersion models. Conduct studies on ammonia and nitrous oxide emission from controlled laboratory studies using soil columns and various manure application practices coupled with field studies to ascertain the impact of different soil and cropping management practices on these emissions. Collect particulate samples using samplers located at various positions from different livestock production facilities to determine the variation of particulate concentration and the VOC compounds attached to the particulates.


3.Progress Report
Through the use of Lidar and turbulence measurements in the vicinity of a poultry facility the first estimates of particulate flux emissions are now being computed. This is critical to accurately evaluating management strategies to reduce emissions of particulates and gases to the atmosphere. Preliminary results clearly show that particulate emissions are not emitted as a Gaussian plume. This has serious implications for modeling efforts that assume Gaussian plume distribution. Additionally turbulent transport processes are shown to be affected by building structures and windbreaks in a manner that cannot be described by simple assumptions. Alternative conservation tillage practices are shown to significantly reduce particulate emissions when compared with conventional methods. As part of our joint efforts with the Space Dynmaics Laboratory (SDL), Environmental Protection Ageny (EPA), and San Joaquin Air Resources Board a study was completed that involved monitoring a dairy for particulate and ammonia emissions. Final report is in progress, but initial results indicate ammonia concentrations of 25-500 ppbv downwind from the dairy. This is result of a collaborative effort with EPA and the San Joaquin Air Resources Board. This progress is related to the NP 206 Action Plan in Problem Areas 1, 2 and 3 and NP 203 Component I.


4.Accomplishments
1. Interactions between Soil and Swine Manure Influence Greenhouse Gas Emissions

Manure applied to soil can stimulate release of greenhouse gases (N2O, CH4) to the atmosphere. A study was published that documents the interactions of soil type and N fertility on greenhouse gas fluxes (N2O, CH4, and CO2) from the soil surface. In a sandy loam soil N2O emissions were significantly different among all N treatments, but in a clay soil only the manure treatment had significantly higher N2O emissions. It is thought that the major differences between the two soils controlling both N2O and CH4 emissions were cation exchange capacity (CEC) and that the higher CEC in the clay soil reduced N availability through increased adsorption of NH4 compared to the sandy loam soil. These findings may lead to improved fertilizer and manure application strategies to reduce soil greenhouse gas emissions. This work relates to Atmospheric Emissions component of the Manure and Byproduct Utilization National Program (NP #206).

2. Lidar and Turbulence Measurements in the Flow Domain of a Poultry Facility

Animal production facilities affect air quality. Estimation of particulate emissions is challenging, complex and highly uncertain. Variations in management practices may lead to unusual emission characteristics with substantial impact on downwind concentrations. A particulate emission study was conducted at a poultry facility in north-central Iowa. This study focused on the effect of buildings and a windbreak on the transport of particulates emitted from three large poultry buildings. Additional measurements on the emission of ammonia from these buildings were also made and found to be well correlated with the transport of particulates. A significant accomplishment was the determination that the flow field in the vicinity of buildings and windbreaks was significantly different than the traditional assumed Gaussian distribution. The results from this study were presented at the 28th Conference on Agricultural and Forest Meteorology, 28 April - 02 May, 2008, Orlando, FL. This work relates to Atmospheric Emissions component of the Manure and Byproduct Utilization National Program (NP 206) and Air Quality Particulate Emissions from Agricultural Industry, Component I (NP 203).

3. Comparison of a sequence of conventional tillage practices with a single pass optimizing tillage implement and its effect on particulate emissions.

Particulate emissions in the San Joaquin Valley are significantly increased as a result of multiple passes made during each cultivation cycle. Typical stable boundary-layer conditions (inversions) can trap much of the particulates near the surface significantly impacting air quality. Reducing or combining multiple tillage passes can reduce particulate loading into the atmosphere. A study was conducted to evaluate the particulate emissions from two different tillage systems following the harvest of cotton in the San Joaquin Valley of California. This study is result of an agreement between ARS and EPA supporting project 3625-11630-002-00D, Emission and dispersion of air quality constituents from agricultural systems. The tillage systems compared were the typical sequential operations with individual tillage implements compared to a single pass tillage implement that combined all of the operations into one pass. Complete fields were evaluated and the study design was developed to measure particulate concentrations at the upwind and downwind positions along each side of the field. These measurements were coupled with micrometeorological measurements to determine atmospheric turbulence and stability. The particulate and micrometeorological measurements were combined with Lidar observations of the complete plume over the field. Ancillary observations were collected of wind speed and wind direction and surface soil water content. All of these observations are being combined to estimate a particulate flux for the different tillage operations. This work relates to the Air Quality Particulate Emissions from Agricultural Industry, Component I (NP 203) and Atmospheric Emissions component of the Manure and Byproduct Utilization National Program (NP 206).

4. Particulates, Ammonium Nitrate and Ammonium Sulfate: Effects on Air Quality in Rural Iowa. Ammonia interacts with the acid gases, namely nitric and sulfuric, to form PM2.5 particulates. These particulates contribute to a decrease in air quality. Ammonium nitrate, ammonium sulfate and particulates were measured at two sites in Iowa. One site was at a swine confinement operation and the other in a rural setting not affected by animal operations. Results indicated no significant differences between the sites due in part to the limited sources of the acid gases needed to complete the formation of PM2.5. This work relates to the Air Quality Particulate Emissions from Agricultural Industry, Component I (NP 203).

5. Hanford, CA Spring 2008 Tillage and Dairy Campaign.

The Central Valley of California is classified as a non-attainment area for PM2.5. One source of PM is the tillage operations associated with crop production and another source is from dairy operations. Measurement of emissions from these operations is both difficult and tedious. Measurements were made over a 6 week period in the Hanford area. Conventional practices and new conservation practices were monitored for dust emissions. Preliminary data indicates a significant reduction using conservation practices. A dairy was also monitored for dust and ammonia emissions. Ammonia concentrations in air ranged from 20 ppbv upwind to nearly 1000 ppbv downwind. Full data analysis including PM values is underway. This work relates to the Air Quality Particulate Emissions from Agricultural Industry, Component I (NP 203) and Atmospheric Emissions component of the Manure and Byproduct Utilization National Program (NP 206).


5.Significant Activities that Support Special Target Populations
In 2008 efforts have been expanded to include poultry and dairy units as well as alternative tillage practices in the San Joaquin Valley, CA.


6.Technology Transfer

None

Review Publications
Pearson, C.H., Ernst, S.M., Barbarick, K.A., Hatfield, J.L., Peterson, G.A., Buxton, D.R. 2007. Agronomy Journal Turns One Hundred. Agronomy Journal. 100:1-8.

Causarano, H., Doraiswamy, P.C., McCarty, G.W., Hatfield, J.L., Milak, S., Stern, A.J. 2008. EPIC modeling of soil organic carbon sequestration in croplands of Iowa. Journal of Environmental Quality. 37:1345-1353.

Jarecki, M.K., Parkin, T.B., Chan, A.S., Hatfield, J.L., Meek, D.W., Jones, R. 2008. Greenhouse gases emission from two soils under N fertilizer and swine slurry. Journal of Environmental Quality. 37:1432-1438.

Last Modified: 9/3/2014
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