Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 21, 2010
Publication Date: January 28, 2011
Citation: Anderson, R.L. 2011. Crop synergism: a natural benefit to improve crop production. No-Till on the Plains Conference Proceedings, January 25-26, 2011, Salina, Kansas. Interpretive Summary: No-till practices have changed crop production in the Great Plains. Instead of rotations comprised of one or two crops, producers are now growing several different crops in their rotations. Crop diversity has provided an ancillary benefit; some crops improve resource-use-efficiency of following crops. For example, dry pea improves winter wheat water-use-efficiency compared with soybean or proso millet as preceding crops. A further benefit is that winter wheat is also more tolerant of weed interference when it follows dry pea. In some way, dry pea affects winter wheat physiology such that yield loss due to weeds are less. Corn is also synergistic to soybean by increasing water-use-efficiency and tolerance to weeds of soybean. Producers can improve crop production efficiency by choosing crop sequences that are synergistic; this approach may provide a way for producers to reduce inputs without sacrificing crop yield.
Technical Abstract: Cropping systems in the Great Plains are changing because of no-till. Rotations now include a diversity of crops in contrast with rotations in tilled systems that grow only one or two crops. This change in rotation design has enabled producers to develop population-based weed management and reduce the need for herbicides to manage weeds. A further benefit of crop diversity is that crop tolerance to weeds may be improved by the preceding crop. Some crops, such as dry pea and corn, improve water-use-efficiency of following crops; these crops also improve crop tolerance to weed interference. This paper reviews a series of studies demonstrating that synergy among crops can affect tolerance to weeds. For example, corn tolerance to Setaria italica interference was more than two-fold higher following dry pea compared with either soybean or spring wheat as preceding crops. A similar level of synergy occurred when dry pea preceded winter wheat and corn preceded soybean. In some way, these crops synergize the following crop to improve tolerance to weed interference. The cause of crop synergy is likely related to a multitude of interacting factors such as growth-promoting substances, microbial changes, and nutrient cycling. Quantifying water-use-efficiency as affected by crop sequencing may provide a method to identify synergy among crops. No-till rotations that include a diversity of crops are synergistically improving land productivity and resource-use-efficiency in the Great Plains. A further benefit is that crop tolerance to weed interference can be increased.