Effects of Residual and Fertilizer Phosphorus on Durum Wheat Production and Wheat Stem Phosphate Levels

Abstract

Collecting additional data to calibrate and refine current guidelines for interpreting soil and plant test values is an ongoing need in Arizona. An experiment was conducted at the Safford Agricultural Center during the 1987 -89 crop years to evaluate the response of 'Aldura' durum wheat to a range of residual soil and fertilizer P levels. Maximum grain yields exceeding 5,500 lbs./A were obtained by banding 50 lbs. P₂O₅/A as triple superphosphate with the seed at planting in 1988. Residual P front phosphorus fertilizer applications up to 80 lbs. P₂O₅/A had no significant effect on grain yields of the succeeding wheat crop. Basal stem PO₄-P tissue analysis seemed reliable in monitoring P nutrition of durum wheat during the vegetative growth period. Observed critical levels of POD P in basal stem tissue for durum wheat at the 3-4 leaf, joint and boot growth stages were 2000, 1200 and 500 ppm, respectively.