A Study in Sulfur - PulseResearch
April 25, 2017
Research aims to help growers choose the best sulfur fertilizer source for their rotation
Sulfur fertilizer is becoming more widely recommended for pulse crops as an important part of the fertilizer mix. However, there are still some unknowns for pulse growers about the long-term effects of these products.
While previous research has examined the end result of sulfur fertilizer on crop yield response and plant sulfur uptake, there is little information available about the transformations that different sulfur fertilizers undergo in the soil from the time of application to crop uptake. “This is important information for growers to have access to in order to predict the relative performance of these products for different crops under varying application conditions,” says Dr. Jeff Schoenau, a Professor of Soil Science in the Department of Soil Science at the University of Saskatchewan.
Dr. Schoenau is leading a research study, funded by Saskatchewan Pulse Growers (SPG), which aims to answer these questions and, ultimately, help pulse growers choose the best sulfur fertilizer source for their short and long-term needs for plant-available sulfur in their rotation.
“Sulfur fertilizers are available in different chemical forms that behave differently in the soil,” he says. “Some fertilizers, such as sulfur, require microbial oxidation to sulfate to become plant-available. Other fertilizers, such as calcium sulfate, are only partially soluble, while others, such as ammonium sulfate and potassium sulfate, are completely soluble.”
Dr. Schoenau’s research, which will be conducted in different soil-climatic zones in Saskatchewan under controlled environment and field conditions, will focus on canola, pea, and wheat crops. “While canola is generally recognized as the crop most responsive to amendment with sulfur fertilizers, the response of other crops like pea and wheat to sulfur fertilization also needs to be investigated to develop better nutrition plans for these crops.”
The research will follow the fate of the fertilizers from the time of application to the uptake and recovery in the plant, as well as their effects on yield. To facilitate this research, Dr. Schoenau will use a soft x-ray microcharacterization beamline (SXRMB) from the Canadian Light Source, cutting-edge technology that facilitates microanalysis of various materials. “For the first time, we are using synchrotron spectroscopy at the Canadian Light Source to successfully follow the conversion of the fertilizer sulfur to different chemical forms in the soil,” he says.
This research will rely on previous research Dr. Schoenau has done in the areas of tolerance to various rates and forms of sulfur and phosphorus fertilizer placed in the seed-row of different canola species and varieties. “This research builds on previous work by expanding into other crops like pea and wheat, and takes the impact of sulfur fertilization beyond seed-row placement tolerance, to transformations of the sulfur in the seed-row that take place throughout the growing season, and interaction with other seed-row placed nutrients like phosphorus,” he says.
Dr. Schoenau hopes that the conclusion of the research will produce valuable new information for pulse growers about using sulfur fertilizer products in our province. He also hopes to be able to provide recommendations as to the most appropriate sulfur fertilizer for different crops, considering factors such as cost effectiveness and plant availability over the time period needed. “The new information on crop response to fertilization will be used by the industry to refine sulfur fertilizer recommendations to growers,” he says.
SPG Investment: $40,738
Co-Funders: Saskatchewan Ministry of Agriculture – Agriculture Development Fund, Saskatchewan Canola Development Commission, and Western Grains Research Foundation (collectively $109,300)
Project Lead: Dr. Jeff Schoenau, Professor of Soil Science, Department of Soil Science, University of Saskatchewan