Water Resources Research Act Program

Details for Project ID 2017AR400B

Regionalizing agricultural field evapotranspiration observations

Institute: Arkansas
Year Established: 2017 Start Date: 2017-03-01 End Date: 2018-02-28
Total Federal Funds: $17,158 Total Non-Federal Funds: $34,317

Principal Investigators: Benjamin Runkle

Abstract: This project is aimed to significantly expand the scope of our research program’s evapotranspiration (ET) measurements to include cotton as well as rice agriculture and to generate lower-cost estimates via the surface renewal technique. This project seeks continuation from a currently running USGS 104B project that has begun to validate the Penman-Monteith equation for estimating ET for rice in Arkansas. The new project proposed will quantify ET rates at 4 rice fields and one cotton field while also testing several observation and modeling techniques to create refined, constrained estimates of ET. The project's main goals are: First, the project will create a partition of ET into its two main components (evaporation and transpiration) in rice fields over three growing seasons (2015-2017) in two growing conditions (AWD and conventional) in each of two locations AND build and interpret an observational record on cotton production. Second, bringing in the surface renewal (SR) technique will enable a test of this much cheaper method (i.e. $5k vs $50k) before suggesting its statewide implementation. Third, a major project benefit is in performing this research at the scale of the production farm using the near continuously recording EC method and associated SR method. This project fits firmly within the research vision of the PI as it supports student research projects, creates opportunities for publication and outreach on research discoveries, and will encourage follow-up funding. This project will support 2 BS students, 1 MS student and 1 Ph.D. student. Due to the strong inter-relationship between the water and carbon cycles, the proposal will significantly enhance the impact of the existing project. The existing research was initiated using the start-up funds of PI Runkle provided by the University of Arkansas College of Engineering and Vice-Provost for Research. Due to the importance of this project’s findings to the state’s water balance, to more sustainable rice yields, and to understanding mechanistic connections between ET and the carbon cycle, there will be a variety of agencies potentially interested in supporting a follow-up study. These funders include the DOE, the NSF, and the USDA, as well as the state’s Rice and Cotton Boards.