Phosphorus Effects On Winter Hardiness Of Winter Barley And Winter Wheat PDF Download

"This research showed a consistent grain yield response to P fertilization at sites where the initial soil test P level was less than 12 ppm. At sites where the initial soil test P level was greater than 12 ppm (and less than 15 ppm), grain yield response was limited to situations where plants had, or were suspected to have, root injury. Maximum benefit was usually achieved with 15 lb/a P, but in some cases, responses to this rate were no different from those achieved with only 5 lb/a P. The significant overall effect of the 15 lb/a P rate on spikes per unit area and grain yield is evidence that applying more than 5 lb/a P is not unreasonable, particularly in years with greater-than-average yield potential."--Summary.