Response of canola, wheat, and pea to foliar phosphorus fertilization at a phosphorus-deficient site in eastern Saskatchewan

Foliar fertilization is a potential strategy to supplement phosphorus (P) requirements when conditions permit. In 2016 and 2017, canola, wheat, and pea were grown in a randomized complete block design trial near Pilger, SK, Canada. Each crop received a total P application of 20 kg P2O5 ha−1, with varying proportions of the P applied as seed-placed monoammonium phosphate (MAP) supplemented with foliar KH2PO4 (0%, 25%, 50%, and 100%) applied prior to anthesis. Under field conditions, yield response decreased as the proportion applied as seed-placed MAP decreased. The 100% foliar-applied P treatment in canola was able to maintain significantly higher yield than the unfertilized control in the absence of seed-placed MAP, indicating some uptake and response. Of the crops evaluated, canola was most responsive to P fertilization. Phytate content ranged from 68% to over 90% of total seed P, with the highest proportions found in wheat grain. Foliar P application had limited effect on phytate and grain iron content, but there appeared to be an inverse relationship between seed-placed MAP and grain zinc concentration that was less evident when P was applied in foliar form. In this study, foliar P application was unable to substitute for seed-placed MAP and overall had a marginal effect on grain yield and P uptake as well as seed nutritional value.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author