|Anderson, Randal - Randy|
Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: 12/15/2001
Publication Date: 1/27/2002
Citation: Anderson, R.L., Tanaka, D.L. 2002. Suggestions for including sunflowers in semiarid rotations. Proceedings Sunflower Research Workshop. Interpretive Summary: Rotations are changing in the semiarid regions of the United States because of no-till and minimum-till systems. Sunflower acreage is rapidly increasing in these regions; however, crop performance of sunflower and following crops is sometimes less than expected. We reviewed the literature to identify agronomic trends that can guide design of rotations with sunflower. Sunflower yield and its impact on following crops are affected by how frequently sunflower is grown in the same field. If grown too frequently, root diseases reduce sunflower yield whereas its high water use and low residue production reduce yield of following crops. Less frequent cropping favors the synergistic effect of sunflower in improving growth efficiency of following crops. With appropriate rotation design, semiarid producers can minimize detrimental effects of sunflower on following crops yet still retain its positive benefits. If sunflower is grown only once every four or six years, yield loss is prevented whereas the synergistic effect of sunflower on growth of following crops increases grain yield.
Technical Abstract: Because of no-till and minimum-till systems, sunflower is now being grown in drier climates such as the Central and Southern Great Plains. However, in some circumstances, producers have experienced deleterious effects when including sunflower in rotations; yield of both sunflower and following crops have been less than expected. We reviewed the literature to identify yagronomic trends related to sunflower frequency of cropping and its interaction with following crops; our goal was to suggest guidelines for sequencing of crops in relation to sunflower. Sunflower seed yield is affected by how frequently it is grown in the same field; yield is highest if sunflower is grown only once every four years. If grown more frequently, root diseases proliferate. Sunflower improves yield of following grain crops, but this response is related to precipitation; yield benefits decline with less precipitation. Impact of sunflower on following gcrops is also related to rotation length. A long-term rotation study is showing that wheat yield in a winter wheat-sunflower-fallow rotation is decreasing 7% per year over time compared to wheat yield in a winter wheat- corn-proso millet-fallow rotation. This yield decline does not occur with a winter wheat-corn-sunflower-fallow rotation. We attribute this effect to low residue production in the three-year rotation. We suggest that semiarid producers plan rotations with sunflower in a cycle-of-four design; this approach accentuates the positive impact of sunflower whereas minimizing its detrimental effects. A second alternative is to rotate two short-term rotations, such as wheat-corn-fallow with wheat-sunflower- fallow.