No-Till Winter Wheat Response to Phosphorus Placement and Rate

Abstract

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 NaHCO3-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.