Evaluation of Triple Super Phosphate as Foliar Fertilizer.

Phosphorus (P) is the second most limiting nutrient in crop production after Nitrogen.  The amount of P in the soil is greater than required by the plants; however, most P in the soil is not available to plants. When P is combined with aluminum, iron and calcium, the formation of very insoluble compounds occur, depending on soil pH. Phosphorus also can be found in organic forms, which can be unavailable to plants. Foliar application of P has arisen as a possible solution to overcome the problems regarding the behavior of P in soils which often results in low P use efficiency. This technique can be used to supplement plant P requirements in deficient soils, permitting the application of lower amounts of P, in periods when it is most needed. In addition, foliar P fertilization could reduce potential environmental concerns related to runoff and erosion, as well as reduce costs related to soil. Field experiments will be conducted with the objective of identifying the influence of triple super phosphate (TSP) as a source of foliar phosphorus fertilizer. The experiment will be tested on winter wheat, corn and soybeans. Yield, P grain concentration and P use efficiency will be evaluated. The use of surfactants to improve foliar P uptake will also be studied.