Submitted to: Field Crops Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/20/2013
Publication Date: 1/27/2014
Publication URL: http://handle.nal.usda.gov/10113/58741
Citation: Nielsen, D.C., Vigil, M.F. 2014. Searching for synergism in dryland cropping systems in the central Great Plains. Field Crops Research. 158:34-42. Doi:10.1016/j.fcr.2013.12.020. Interpretive Summary: Claims have been made regarding the beneficial synergistic effects of growing corn ahead of winter wheat or proso millet, or growing field pea ahead of wheat. The claimed synergistic effect was improved water use efficiency, or growing more crop yield with less water. This paper reviews the sources and analyses of the original data sets and adds more years of data in order to evaluate these claims of synergism. This more extensive analysis found no evidence of synergism leading to improved water use efficiency when corn or pea preceded winter wheat or proso millet in a crop rotation.
Technical Abstract: Previously published research reported a “synergistic effect” of corn on winter wheat (Triticum aestivum L.) and proso millet (Panicum miliaceum L.) water use efficiency when corn (Zea mays L.) was the preceding crop for dryland cropping systems in the central Great Plains, i.e., less water was required to grow a unit of wheat or proso millet when corn was the preceding crop. A similar synergistic effect of field pea (Pisum sativum L.) on winter wheat has also been reported. The purpose of this study was to examine longer-term data sets than originally analyzed in order to confirm or refute the previously reported synergism. Yield and water use data were acquired from a long-term crop rotation study conducted at Akron, CO from 1996 to 2011. The analysis of these data did not support a conclusion that corn has a synergistic effect on wheat or millet production nor the conclusion that pea has a synergistic effect on wheat.