A New Look at Row and Broadcast Phosphate Recommendations for Winter Wheat1

Phosphate fertilizer recommendations for winter wheat have traditionally been in terms of doubling the row applied P rate if broadcast application is to be used. A literature search failed to locate a significant amount of supportive data for this practice. The experiments reported here were conducted to determine if there is a consistent relationship between broadcast and row applied P rates for winter wheat and if so, what that relationship is. Six field experiments were conducted over a 2 year period on soils of, the Typic Argiustoll subgroup. Treatments were five rates of 0‐46‐0 (0, 11, 22, 34, 45 kg P/ha) applied as either preplant broadcast or drilled with the seed. All experiments were on soils that responded positively to P fertilization. Results contradicted the concept of a 2:1 ratio of broadcast to row P application as standard practice. The relative effectiveness of row and broadcast methods changed with changing soil tat P levels. Low soil test locations exhibited an effective ratio of about 3:1 while medium soils tests had ratios of 1:1.