Nutrient Content and Release from Soybean Residues in Comparison to Other Pulse Crops in Saskatchewan.

Soybean (Glycine max (L.) Merr.) production is expanding in Western Canada due to the development of short-seaon varieties suitable for Western Canada. As a legume, soybeans can fix a significant portion of nitrogen that they need, which is beneficial to soil nutrient store and succeeding crops in rotation. While the rotation benefits have been well documented for other traditional Saskatchewan pulse crops, such as pea (Pisum sativum L.) and lentil (Lens culinaris), information is lacking on short-season soybean nutrient uptake and requirement, content and release rate of nutrient in comparison to traditional pulse crops utilized in rotation in Saskatchewan. Therefore, this study aimed to determine the plant nutrient content, uptake and composition of the residue of soybean grown under Saskatchewan conditions, and the contribution that the residue makes to nutrition and yield of following spring wheat in comparison to pea and lentil. The study utilized three modern short-season varieties at two sites in the Dark Brown soil zone and two sites in the Black soil zone in Saskatchewan. Employment of 15N dilution technique was used to estimate nitrogen fixation and cycling in the plant-soil system.