Evapotranspiration of irrigated and rainfed maize and soybean

We have been making year-round measurements of mass and energy exchange in irrigated and rainfed maize-soybean systems for the past several years. In this conference, we will present the seasonal distribution of evapotranspiration (ET) of these crops during the first five years of our study. The contributions of the growing season ET and "non-growing season" (fall-winter months) ET to the annual total ET will be quantified. The role of surface mulch in explaining the interannual variability of the non-growing season ET will be investigated. Water use efficiency of these cropping systems will be quantified and examined in the framework of Tanner and Sinclair (1983, Efficient water use in crop production: Research or re-search? p. 1-27. In H.M. Taylor et al. (ed.) Limitations to efficient water use in crop production. ASA, CSSA, and SSSA, Madison, WI).