Influence of phosphorus, nitrogen, and potassium chloride placement and rate on durum wheat yield and quality

Information regarding the impact of P and KCl rate and placement in conjunction with N rate on durum wheat (Triticum turgidum L. var. durum) is limited in the Great Plains. Our objectives were to determine the effects of N, P, and KCl fertilizer rate and P and KCl placement on grain yield and quality of durum wheat grown on low P soils. Nine combinations of N and P fertilizer and five combinations of N, P, and KCl applied with the seed and in a side band, were compared over 3 yr at Indian Head, SK, in fields with soil P levels <9 kg ha(-1). Grain yield increased 15% as N application increased from 45 to 140 kg ha(-1). Grain yield increased by 10% as the P rate increased from 0 to 17 kg ha(-1) under dry conditions in 2003, but not in 2002 and 2004. No interaction was detected between N and P for grain yield. Grain yield was unaffected by KCl application and P or KCl placement, in the high K soils included in the study. Grain protein increased from 123 to 150 g kg(-1) as N fertilizer rate increased, but decreased from 140 to 136 g kg(-1) as more P was applied. However, Red smudge decreased as P increased. Results from this study indicate that N application does not affect the amount of P required by durum wheat and that yield responses to P can occur in soils low in P under dry conditions.