Phosphorus fertilizer by-product effect on the interaction of zinc and phosphorus in corn and soybean

The application of high phosphorus fertilizer by-products to farmland is a common practice used to reduce storage volume and disposal cost. However, because Iowa soils are generally high in both phosphorus and zinc, there are environmental and fertility questions concerning their application to farmland. A greenhouse study was conducted to determine the effect of a soil-applied fertilizer by-product on the zinc-phosphorus relationship in corn and soybean plants grown on three Iowa soil series: Belinda, Downs, and Haig. The soils were mixed with a high-phosphorus fertilizer by-product and plants were also collected and analyzed for phosphorus and zinc content and uptake. Soil samples were analyzed for phosphorus and zinc content. The experiment was repeated, switching pots to assess the residual effect after one cycle of rotation. The treatments were arranged in a totally randomized design with three replications. The results indicated that the high phosphorus fertilizer by-product increased soil and plant concentrations of phosphorus in soybean and corn plants and soils. However, the increase of P concentration did not induce changes in the phosphorus-zinc interaction in corn and soybean plants in any of the studied soils. Key words: Phosphorus, corn, soybean, zinc, sludge, by-products, Zn-P relationship, zinc-phosphorus interaction