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United States Department of Agriculture

Agricultural Research Service

Research Project: Preserving Groundwater Quality and Availability for Agriculture

Location: Watershed Physical Processes Research Unit

2013 Annual Report

1a.Objectives (from AD-416):
Reduce reliance on groundwater and maintain the quality of groundwater and surface water sources for agricultural uses through improved water management in agricultural systems.

1b.Approach (from AD-416):
USDA-ARS and Arkansas State University (ASU) are both interested in the preservation and enhancement of water resources in both the Arkansas Delta and the Grand Prairie. While water availability (both surface and groundwater) is reasonable to the east of Crowley’s Ridge, water quality is an issue. To the west of Crowley’s Ridge, both water availability (particularly groundwater) and water quality are serious concerns. Plant-based agriculture in Arkansas (primarily located in the eastern half of the state) is dependent on irrigation and Arkansas ranks 4th in the U.S. in irrigated acreage. Thus, the sustainability of agriculture and water resources in Arkansas are very closely linked. Ways must be found to increase the efficiency of water use while also improving the quality of the water resources in the state.

In addition to development of modeling resources, both groups will work to support the broad dissemination of modeling techniques via known scientific research channels such as TerraGrid. This will provide others with experience gained by researching groundwater issues in the Mississippi Delta.

3.Progress Report:

The United Stated Department of Agriculture (USDA) Agricultural Research Service (ARS) is working closely with the Arkansas State University (ASU) on several projects. USDA ARS personnel have established collaborative relationships with university staff and faculty in several departments. Three students (two graduate and one undergraduate) are supported through this agreement. The first graduate student (GS1) began at ASU in August of 2012 and is working toward a PhD in environmental sciences. The research of GS1 is focused on development of field sensor data collection and communication networks through the incorporation of technology into water management. GS1's salary, fees and tuition are covered under this agreement and another Specific Cooperative Agreement (SCA) with ASU. The second graduate student (GS2) began as an hourly technician in the early summer of 2012 and switched to graduate school in January of 2013. GS2's salary, fees and tuition are split between this agreement and another SCA with ASU. The undergraduate began in spring of 2013 and took over the technician responsibilities of the student just described.

Water quality characterization in surface runoff and irrigation return flows is important to sustainable agriculture in the region. This agreement fully or partially funded three water quality monitoring projects. The first is water quality monitoring at a nearby reservoir-tailwater recovery system. It was sampled 8 times at 13-16 locations measuring nutrients, solids, alkalinity, hardness, Chlorophyll, acidity, conductivity, and dissolved oxygen. Additional funding from USDA Natrual Resources Conservation Service (NRCS) is anticipated from a state funded Conservation Innovation Grant (CIG) to continue this research in earnest.

The second study utilized the support of the technician described above to provide maintenance and some data collection at the ten edge-of-field water quality monitoring sites that are collaboratively managed by USDA-ARS and ASU and funded through the Mississippi River Healthy Basins Initiative (MRBI). These ten sites are part of a state-wide network described in a paper published in the Journal of Soil and Water Conservation in 2013. The GS1 student has been integral in improving the edge-of-field communication and programming, including remotely triggered field cameras for monitoring field activities. Data from the edge-of-field sites has been presented at several conferences by both USDA-ARS and ASU researchers, including Society of Environmental Toxicology (Long Beach, CA), American Geophysical Union Fall Meeting (San Francisco, CA), Soil and Water Conservation Society Annual Meeting (Ft. Worth, TX), and American Society of Agricultural and Biological Engineers (Kansas City, MO).

The third water quality project was an experiment to determine variability in water quality due to flood release practices from fields that stored water over winter for waterfowl habitat.

Access to research sites to evaluate alternative cropping systems was provided by ASU. The research farm at ASU is home to an extensive biofuels study. This study was one of the cornerstones of a National Institute of Food and Agriculture (NIFA) proposal submitted by USDA-ARS, ASU, University of Missouri and University of Nebraska.

Water management practices impact yield and the use of resources in agriculture both locally and regionally. Incorporating technology into water management is the primary focus of the GS1 student funded through this agreement. The GS1 has worked with collaborators from USDA NRCS, the White River Irrigation District and Diesel Engine Motors to plan needed work for sensor and radio telemetry for integration with existing pump and motor systems as well as independent field monitoring units (monitoring soil moisture, water flow, water depth, monitoring field pump and motor). Funds from this agreement were used to purchase equipment for a prototype system of a wireless sensor network to monitor water depth in a nearby production-sized rice field. In addition, GS1 worked with a graduate student in agriculture that is researching irrigation planning and design. GS1 developed circuitry and remote data access for custom sensors for detecting irrigation wetting front and water depth using different technologies (i.e. XBee, Wi-Fi, Synapse remote telemetry components). In collaboration with the College of Agriculture and Technology, the GS1 student has helped establish, troubleshoot, update hardware and perform program maintenance for weather stations instrumentation, datalogger and public web access portal at three university weather stations (

Funds from this agreement were used to purchase one eddy covariance-energy balance (EC-EB) system of sensors in 2011. This system was deployed in 2012 in a large rice field that was conventionally irrigated. Detailed plant staging information was collected from this field and correlated to water use and energy balance measurements made from the EC-EB system. A manuscript of the findings from this research is being completed and should be submitted before October 1, 2013. USDA-ARS was able to purchase a second EC-EB system in late 2012. The two EC-EB systems are currently deployed in a conventionally flooded and an intermittently flooded field to monitor water use and plant response to these contrasting water management practices. All students funded through this agreement worked on the preparation and deployment of these systems. The GS1 student continues to monitor and troubleshoot data issues as they arise from these systems.

Resources from this agreement were used to support and participate in the Arkansas Soil & Water Education Conference (ASWEC) in several ways. Attendance at ASWEC is comprised of producers, state and federal agency personnel and regional university faculty and students. Funds from this agreement were used to pay for the rental of the facility. Both graduate students that are supported through this agreement presented their research at the conference- “Remote telemetry using near-realtime data collection for Mississippi River Healthy Basins Initiative (MRBI) monitoring network “ and “Proposal to Study Water Quality of an Agricultural Reservoir and its Effects on Macroinvertebrates”. This research is in direct support of objective 2 and 4 described above.

“Create @ Astate” is a campus wide conference that encourages scientific and creative exchange for students. One of the graduate students funded through this agreement presented their initial findings from their research at this conference.

Laboratory and office space continues to be provided by the university. Expanding numbers of undergraduate summer help and a visiting international graduate student has required a doubling of student desk space areas occupied. Additional laboratory space was provided for approximately one month to accommodate the testing of two eddy covariance-energy balance towers prior to field deployment.

Last Modified: 7/22/2014
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