Enhanced Efficiency Phosphorus Application for a Corn-Soybean Rotation.

With high fertilizer costs, farmers are interested in reduced phosphorus (P) fertilizer application rates and use of enhanced efficiency P fertilizer applications or treatments. AVAIL®(Specialty Fertilizer Products, Leawood, KS) and P₂O₅ Max (Rosen’s Inc., Fairmont, MN) are commercially-available products that are intended to enhance the efficiency of  P fertilizers. The first objective of this research initiated in 2010 was to determine the effects of tillage/fertilizer placement (no-till (NT)/surface broadcast or strip-till (ST)/deep banding), monoammonium phosphate (MAP) rate [0, half the recommended rate (56 kg ha^-1), and recommended rate (112 kg ha^-1)], and the presence and absence of two enhanced phosphorus efficiency products (Avail® and P₂O₅-Max®) on a corn-soybean rotation. The second objective was to determine the effect of liming application (0 and recommended rate), P source [non-treated control and a broadcast application of diammonium phosphate (DAP) or triple superphosphate (TSP)], and the presence and absence of two enhanced phosphorus efficiency products (Avail® and P₂O₅-Max®) on a corn-soybean rotation.