Effect of residue management on growth, yield and quality of soybean
Ramona Mohr and Aaron Glenn (AAFC-Brandon)
To determine the effect of residue management on soybean planted in early versus later May
Manitoba’s soybean industry has grown rapidly over the past decade. The introduction of short-season cultivars has resulted in an expansion in production from traditional growing areas in the Red River Valley to shorter-season areas, leading to a record soybean acreage of 1.6 million acreas in 2016 (Statistics Canada 2016). Despite ongoing improvements in soybean genetics, soybean is inherently a cold-sensitive crop that can be prone to low-temperature damage in both the spring and the fall. As such, planting either too early or too late may pose a risk. Management practices that modify the micro-climate that soybeans are exposed to early in the growing season, and/or that give the crop a competitive advantage under stressful conditions, may help to create a set of conditions that are more conducive to soybean establishment, growth and yield and thereby potentially reduce production risk.
A series of small-plot and controlled environment studies were initiated in fall 2017 to better understand the effect of management on early-season temperature and moisture conditions and, in turn, on soybean establishment, growth, yield and quality. In 2019, early seeding increased yield at 2 of 3 sites, suggesting the potential benefit of early planting in a year like 2019 where spring frosts were not an issue, but where an early and cold fall delayed crop maturity and harvest. These results contrast with 2018 where planting date had no effect on yield. Residue management affected soybean yield only at Indian Head in 2019, with tall stubble enhancing yield in some cases, similar to the results at this site in 2018. These are preliminary results only from ongoing field trials.
The Canadian prairies mark the northern fringe of soybean production in North America.
Despite ongoing improvements in soybean genetics, soybean is inherently a cold-sensitive crop that requires a relatively long growing season. Frost, and near freezing temperatures in spring and fall can damage soybean. Early planting into cool and wet conditions can increase seedling disease and reduce plant stand (NDSU Extension Service 2010), with soil temperature acting together with soil moisture to affect establishment (Helms et al. 1996a; Helms et al. 1996b; Wuebker et al. 2001). Residue management practices may influence soil temperature as well as soil moisture, and thus potentially affect early-season growth.