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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Publications at this Location » Publication #307170
Title: Portable canopy chamber measurement of evapotranspiration in corn, soybean and reconstructed prairie

Author
item LUO, CHENYI - Iowa State University
item WANG, ZHUANGJI - Iowa State University
item Sauer, Thomas
item HELMERS, MATT - Iowa State University
item HORTON, ROBERT - Iowa State University

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: To meet the increase of energy demands, the biofuel production in the US is increasing. Because of this demand, land transformation from row crop production to bioenergy production with perennial plants is promoted in the Midwest. This transformation may impact the field water balance, and it is important to understand how the different cropping systems affect the field water balance. Evapotranspiration (ET) is a vital component of the field water balance, and accurate determination of ET is particularly important. The objective of this study is to quantify the seasonal and diurnal trends of ET in three cropping systems and compare the field water balance among different cropping systems. Three cropping systems, including corn and soybean in a corn-soybean rotation, and reconstructed prairie, were studied at the Comparison of Bio-fuel Systems (COBS) research site in central Iowa. Portable canopy chambers were used to measure ET in the different cropping systems during the 2014 growing season. Three different chamber sizes were used to match different crop growth stages. The validation of the accuracy of the portable canopy chamber measurements is proved by laboratory tests. The diurnal change of ET is collected with the portable canopy chamber once a week. The plant indicators (plant height, leaf number, and leaf area) are be measured to show the proportional relationship with ET flux. Potential evaporation flux is also estimated with weather data to compare with the chamber ET. The chamber measured ET flux of corn is generally the largest value, and the ET flux of the reconstructed prairie is larger than the soybean. Potential evaporation is generally larger than measured ET flux, due to the soil water deficit. The field water balances of the three cropping systems are determined with measurements of precipitation, ET flux from the chambers, the change of soil water storage, and the subsurface drainage volumes.