The influence of nitrogen, phosphorus and potash fertilizer application on oat yield and quality

Western Canada has become one of the key production areas for oat (Avena sativa L.) in North America. Limited information is available regarding fertilizer management strategies to optimize yield and quality in this environment. An experiment was conducted at two locations in southern Manitoba in 2000, 2001 and 2002 to assess the impact of factorial combinations of N (0, 40, 80, 120 kg N ha(-1) as urea), P (0, 13, 26 kg P ha(-1) as monoammonium phosphate), and KCl (0, 33 kg K ha(-1)) on the growth, yield and quality of AC Assiniboia oat. Low to moderate N rates significantly increased yield, with optimum relative yield achieved with a plant-available N supply of approximately 100 kg N ha(-1). Increasing N rate also increased lodging and reduced test weight, kernel weight and kernel plumpness, suggesting that optimal N management must balance yield improvement against reductions in grain quality. Phosphorus application increased yield in 2 of 6 site-years, but had no overall effect on quality. Application of KCl resulted in small increases in yield (88 kg ha(-1)), kernel weight and kernel plumpness on moderate to high K soils, which were not likely to provide a significant economic benefit. The lack of consistent interactions among N, P, and KCl suggests that these nutrients may be managed individually.