|DOLD, CHRISTIAN - Orise Fellow|
|Sauer, Thomas - Tom|
|WACHA, KENNETH - Orise Fellow|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2018
Publication Date: 5/18/2018
Citation: Dold, C., Hatfield, J.L., Prueger, J.H., Sauer, T.J., Wacha, K.M. 2018. Water use efficiency in corn-soybean cropping systems in the Midwestern US [abstract]. In: Preceedings of 33rd Conference on Agriculture and Forest Meteorology, American Meteorological Society (AMS), May 15-18, 2018, Boise, Idaho.
Technical Abstract: The Midwestern US agriculture is dominated by corn and soybean production, that are grown primarily under rain-fed conditions. Therefore, the prevailing weather conditions can have a high impact on yield. The aim of this study was to analyze evapotranspiration (ET), gross primary production (GPP), and crop yield in a Midwestern US corn-soybean rotation. We analyzed eddy flux data from a 9.1 m eddy co-variance (EC) tower, covering two fields cropped with corn and soybean in annual rotation from 2007 - 2015. The studied period comprised a wide range of climatic conditions with dry and wet as well as cold and warm years. Annual rainfall was between 578 and 1441 mm, while average air temperature was 17.1 – 20.1 and -2.3 – 3.5 °C in the growing and off-season, respectively. The average GPP was 966 g C m-2 yr-1. The average ET was 622 mm yr-1 and 470 mm-1 for the whole year and the growing season, respectively. The average water use efficiency (IWUE*) 15.9 g C x kPa mm-1 for the growing season. The IWUE* was significantly (p < 0.05, n = 9 years) related to rainfall (R2 = 0.57), with increasing IWUE* at decreasing precipitation. This is probably connected to a trend of increasing ET and decreasing VPD under high rainfall and vice versa, while GPP showed no such trend. In a second step, water use efficiency will be calculated using eddy flux data from several EC towers in the region, as (1) IWUE* as well as (2) crop yield divided by ET, using footprint analysis and yield maps. Both, estimates from several towers and combined crop estimates are important to model and analyze regional water use efficiency in corn-soybean rotations.