Continuous Zero-till Organic Wheat Production: Defining the Limits.

Organic farmers in the U.S. northern Great Plains are interested in reducing tillage frequency and intensity to improve both crop performance and soil quality when growing wheat [Triticum aestivum L. emend. Thell.] and other grain crops. A long-term study was established in 2009 to determine if economic wheat yields could be maintained following the establishment of continuous no- or zero-till (OZ) under organic management. Current cropping systems have been in place since 2010. Results suggest that organic wheat yields cannot be maintained at economic levels by year five after continuous OZ methods first are adopted, even if biological (i.e., grazing) and cultural control methods, along with the application of natural products, are used in attempts to suppress weeds. Results of this study suggest that Organic ZT phase farming, where ZT practices are rotated with tillage, is the best near-term strategy for incorporating ZT practices into cropping systems that are comprised of annual field crops.