Enhancing corn and soybean yields in Ontario

Gone are the days of grandpa getting the tractor and 3 furrow plow out to work the whole farm each fall after harvest. For decades now, producers have been developing and adapting new technologies and practices to optimize land use, while continuing to care for it. Thirty-one years of data evaluated by the University of Guelph demonstrates the various effects of changing tillage practices and crop rotations in Ontario field crop production.

It seems as though our seasons are becoming more and more variable each year, with bigger temperature swings and dramatic changes in precipitation. With more time between rain events, crops need to be efficient in water conservation and usage.

A research report published in 2015 titled “Increasing Crop Diversity Mitigates Weather Variations and Improves Yield Stability”, demonstrates that more diverse crop rotations beyond corn and soybeans is a key factor in yield increases. Reducing and adjusting tillage is also shown to have a significant effect on yield. As part of Dr. Bill Deen’s research team at the University of Guelph, Amelie Gaudin and colleagues studied thirty-one years of weather data from the University of Guelph, Elora Research Station. Both crop rotations and tillage data were evaluated for corn yield advantages, corn and soybean yield stability and any other potential benefits.

Their findings showed moving from a 2 crop (corn-soybean rotation) to a 3-crop rotation (adding wheat to corn-soybean rotation) increased the following average soybean yields by 13 per cent. The 5-year average for Ontario soybeans is 49 bu/ac. The more crops in a rotation, and the more times the complex rotation repeated, the better the long-term effects.

Corn and soybeans displayed different yield reactions to the various methods of mitigating stresses. While corn appeared to favour crop rotation and diversity, adjusting tillage practices had little effect on yield and stress tolerance. However, soybeans preferred changes in tillage programs over rotation diversification. Less tillage on soybean ground resulted in more consistent crop stress mitigation than conventional tillage. Tillage and crop diversity had a greater positive effect on crop response to heat and drought than they did for wet and cold periods. These practices offered some yield stabilization for wet and cold periods (or entire seasons), but it was lesser than the effects noted during drought stresses.

More recent research published in 2020, confirmed the earlier results. Sites across Canada and the United States saw an average yield increase of 28.1 per cent across all conditions when crop rotations were more diverse (Long-Term Evidence Shows that Crop-Rotation Diversification Increases Agricultural Resilience to Adverse Growing Conditions in North America). They also saw a large reduction in yield losses on drought years. Sites used both synthetic nitrogen and organic nitrogen, and varied tillage systems between no till, reduced till and conventional tillage.

Adding small grain cereals, forage legumes and other niche crops can add some costs and can complicate management practices, but does it have a place on your operation? The more complex the rotation, and the more diverse the tillage practices, the higher the potential to reduce crop stresses. Add in the potential benefits for weed, pest and disease control, and the value may soon dramatically outweigh the cost for your farming operation.

– Click here to read the July 6 field crop report at the Field Crop News website.