Research conducted at the University of Saskatchewan’s (USask) Department of Soil Science, has demonstrated that pulses can be sensitive to seed-placed starter nitrogen, phosphorus, and sulphur fertilizer products, with lentils, peas, and chickpeas being the most sensitive.
Dr. Jeff Schoenau, a soil fertility professor and Ministry of Agriculture Strategic Research Program (SRP) Chair in Soil Nutrient Management, and his team conducted a controlled environment study and a field experiment evaluating the emergence, yield, and nutrient uptake responses to the starter seedrow placed fertilizer blends and combination products containing nitrogen, phosphorus, and sulphur in soybeans, green peas, faba beans, black beans, small red lentils, and Desi chickpeas.
They discovered that of all six pulse crops seeded, there was the strongest injury potential to starter fertilizer placed in the seedrow with lentils, peas, and chickpeas. Soybeans and black beans could tolerate slightly higher rates of starter seedrow fertilizer, and faba beans were the least affected pulse crop.
Based on the results of this study, pulses that begin nitrogen fixation early, and fix large amounts of nitrogen such as faba beans and peas would require the least, if any, amount of starter nitrogen.
“Overall, 10 kilograms nitrogen per hectare or less appeared to be the limit as starter fertilizer rate in the seedrow expressed on a N basis for the blends and products for the most sensitive, least responsive crops like lentils, peas, and chickpeas,” says Schoenau.
Schoenau also notes that in the controlled environment study, soybean, black bean, and faba bean could tolerate slightly higher rates of nitrogen, up to 20 kg N/ha, depending on crop and fertilizer blend or product. Placement in a separate band away from the seedrow is a means to avoid injury issues with reduced emergence and low plant populations when higher rates are desired. The studies were conducted on a loamy textured Brown Chernozem under good moisture conditions. Sandy texture and dry conditions increased injury potential.
“Dr. Schoenau’s work on pulse starter fertilizer provides growers with clear recommendations to get these crops the nutrients they need while balancing seed safety,” says Dr. Dave Greenshields, Director of Research and Development with Saskatchewan Pulse Growers. “Adequate fertility helps to get pulses off to a good start, which makes them better able to withstand biotic and abiotic stress and contributes to yield at harvest.”
The results of this research can be viewed on the Saskatchewan Pulse Growers website. The research was funded by the Saskatchewan Agriculture Development Fund and Saskatchewan Pulse Growers.
