Foliar Application of Agxplore Prevent Phosphorus Aid in Winter Wheat.

Adequate soil phosphorus (P) levels support root and shoot growth, promote maturity, increase water use efficiency and crop yield. P availability to plants is directly affected by soil pH. At alkaline pH values (higher than pH 7.5), phosphate ions react with calcium (Ca) and magnesium (Mg) to form less soluble compounds. Many soils in southern Idaho have pH values between 7.5 and 9.0., falling into the soil category of vey low P avaialbility. Prevent (AgXplore International, Parma, MO) with CrossLink Technology  is a phosphorus (P) management aid designed to prevent P fixation in the soil and enhances P availability, uptake, and use efficiency. The objective was to evaluate the efficacy of Prevent P management aid for increasing P availability and efficiency in wheat. Experiments were established in the fall of 2015 at two fields at the University of Idaho (UI) Parma Research & Extension Center. Winter wheat (var. Stephens) was seeded at 155 kg ha^-1 seeding rate into 3 x 6 m plots. The study consisted of 7 treatments replicated 8 times. Nitrogen (N) fertilizer urea (46-0-0) was applied at rates to achieve the UI N recommendations for winter wheat of 280 kg ha^-1. Wheat plots were treated with monoammonium phosphate (MAP; 11-52-00) at 100, 75, or 50% of recommended rate. The MAP was either treated or untreated with Prevent prior to application. One treatment (P-unfertilized) was fertilized with N only, and MAP was omitted. Whole plant above ground biomass samples were collected at Feekes 5-6, and Feekes 10 and analyzed for P content. At Feekes 5-6, Normalized Difference Vegetative Index (NDVI) was measured to access crop nutrient status using a GreenSeeker handheld optical sensor (Trimble Navigation Ltd., Sunnyvale, CA) . SPAD, 502 meter (Spectrum Technologies Inc., Aurora, IL) was used at Feekes 5-6 to estimate chlorophyll content. At maturity, the effect of MAP treated and untreated with Prevent P aid applied at various rates on wheat rain yield, test weight, grain protein and P content were evaluated.