Top Crop Manager: How many years are too many years?
Soybeans offer valuable benefits in a crop rotation. However, like any crop, if you grow soybeans too often, problems can start to emerge. What is the optimal rotational frequency of soybeans that will sustain strong yields, good economic returns and healthy soils?
Agronomist Yvonne Lawley investigated that question in an eight-year rotational study in central Manitoba.
The first four years
“When this study started in 2014, soybeans were rapidly expanding in Manitoba rotations. That was being driven in part by important breeding work and having early-season soybeans available,” explains Lawley, an assistant professor in the Plant Science Department at the University of Manitoba (U of M). “But it was also driven by market and weather conditions. It was very profitable to grow soybeans. And Manitoba was in a wet cycle and soybeans were doing really well relative to other crops.”