Agronomic evaluation of a homogeneous nitrogen-phosphorus-sulphur fertilizer in southern Manitoba

Field studies and a growth chamber study were conducted to evaluate the effect of a homogeneous nitrogen-phosphorus-sulphur (NPS) fertilizer on the emergence and crop utilization of phosphorus (P) and sulphur (S). In the field study, spring wheat (Triticum aestivum L. cv. AC Barrie) and spring canola (Brassica napus L. cv. DKL 34-55) were grown in southern Manitoba and fertilized with NPS, monoammonium phosphate (MAP) + ammonium sulphate (AS), MAP + elemental S-bentonite (S°), MAP only and a control (no P or S); and S was applied at 0, 5, 10, 15 and 20 kg ha'. Wheat and canola emergence was not affected by any of the seed-placed P and S fertilizer sources or S rates used in the study. The NPS and other P fertilizer sources increased dry matter yield 6--10% in wheat at midseason but not at maturity; canola yields were not increased by P and S fertilization at any stage. At midseason, all of the phosphate fertilizers increased P uptake by 8--13% in wheat and 23--45% in canola, while NPS and MAP + AS increased S uptake by wheat 7--9%. At maturity, all of the P fertilizers increased total P uptake by 9--12% in wheat but not in canola, and all responses to S fertilization had disappeared. (Abstract shortened by UMI.).