No‐Till Winter Wheat Response to Phosphorus Placement and Rate

Phosphorus deficiency of winter wheat ( Triticum aestivum L.) is common in the central Great Plains. Acceptance of reduced and notill systems for wheat production has made soil incorporation of broadcast P fertilizer more difficult. This field study evaluated the effectiveness of P placement methods (surface broadcast with and without incorporation and banded below the seed zone) for no‐till winter wheat production at rates of 0, 34, 67, 101, and 134 kg P ha −1 in 1986 and 1987. Subplots of 0 and 56 kg N ha −1 were included with each P rate. A Rosebud‐Escabosa loam soil (fine‐loamy, mixed, mesic Aridic Argiustoll‐Calciustoll) with a NaHCO 3 ‐extractable P level of 10 mg P kg −1 soil (medium soil test level) and a pH of 7.8 was used. Phosphorus placement had no significant effect on grain yield. Grain yields increased curvilinearly with increasing P rate up to 101 kg P ha −1 for both broadcast and banded treatments. Straw yields also increased curvilinearly with increasing P rate. Nitrogen fertilization enhanced grain protein by 6% and also grain P uptake. Total P uptake by grain increased with increasing rate of P application. Broadcast applications of P without incorporation under no‐till conditions effectively increased winter wheat yields on a soil testing medium in available P. When sufficient P was applied to correct P deficiency in winter wheat, method of placement had little effect.