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ARS Home » Southeast Area » Jonesboro, Arkansas » Delta Water Management Research » Research » Publications at this Location » Publication #352492

Research Project: Preserving Water Availability and Quality for Agriculture in the Lower Mississippi River Basin

Location: Delta Water Management Research

Title: Eddy covariance measurements of carbon dioxide and water fluxes in Mid-South U.S. cotton

Author
item Reba, Michele
item Fong, Bryant - Orise Fellow
item Teague, Tina - Arkansas State University
item Runkle, Benjamin - University Of Arkansas
item Suvocarev, Kosana - University Of Arkansas

Submitted to: Arkansas Agricultural Experiment Station Research Series
Publication Type: Experiment Station
Publication Acceptance Date: 4/24/2018
Publication Date: 10/1/2018
Citation: Reba, M.L., Fong, B.N., Teague, T.G., Runkle, B.R., Suvocarev, K. 2018. Eddy covariance measurements of carbon dioxide and water fluxes in Mid-South U.S. cotton. Arkansas Agricultural Experiment Station Research Series. 652:93-97. http://arkansas-ag-news.uark.edu/pdf/652_Summaries_Arkansas_Cotton_Research_ 2017.pdf.

Interpretive Summary: Eddy covariance (EC) is a micro-meteorological technique used to quantify land-atmosphere interaction of CO2 and H2O fluxes. It is the most direct and defensible method to measure field-scale fluxes. In this study, EC was used to measure CO2 and H2O fluxes over a production sized cotton field under typical management for the 2016 and 2017 production season. Measured values of H2O flux were lower than those measured in the arid cotton growing regions but aligned with lysimeter measurements in the humid Mid-South. Measurements from this study will contribute to research efforts to refine inventories of agricultural GHG emissions and may influence management, specifically irrigation, in the humid mid-south.

Technical Abstract: An eddy covariance (EC) system was used to quantify carbon dioxide (CO2) and water (H2O) fluxes as net ecosystem exchange (NEE) and crop evapotranspiration (ET), respectively, in a production-sized cotton field in Northeastern Arkansas in 2016 and 2017 growing seasons. Average ET was 0.13±0.01 in d-1 during 2016 and 0.14±0.01 in d-1 during 2017 growing season. The average ET values were similar to results from lysimeter studies conducted in humid SE US climates, but lower than observed in studies in arid regions; this variation was likely due to comparatively higher relative humidity and lower solar radiation in the southeastern US. NEE decreased from emergence until the first square stage due to increasing gross primary productivity (GPP), remained constant during squaring and flowering periods, and then increased after physiological cutout during boll maturation due to decreasing GPP. These findings will contribute to research efforts to refine inventories of agricultural GHG emissions and improve water use and irrigation management in the humid mid-south.