Residue of Phosphorus From Banded Soluble Phosphate Fertilizer and Their Effects On Growth of Maize.

To evaluate the residual levels of phosphorus (P) from banded application of phosphate fertilizers in the furrow, the residual level from three sources of soluble P diffused into this soil, and their effects on the growth of maize was carried out a  greenhouse experiment. The plants cultivated in plastic pots with 5 kg of clayed soil. The treatments were four doses of phosphorus at 75, 50, 300 and 600 mg P kg^-1 soil from triple superphosphate (TSP), superphosphate (SPS) and phosphate monoammonium (MAP), plus a control without the fertilizer. The residues of phosphorus were those remaining in the furrow (RP_FRW) and the phosphorus diffused into the soil (RP_EFL). The banded application of the fertilizer was through cylinders made of shade net fabric put into the soil to simulate the banded application. The maize plants were evaluated during the initial stages of growth. The experimental design was the complete randomized blocks using a factorial arrangement (4 x 3 x 2) + 1 with five replications. We evaluated the residual amount and content of P from each fertilizer applied into the furrows as total phosphorus (P_TOTAL), phosphorus soluble in neutral ammonium citrate + water (P_NAC) and the phosphorus soluble in water (P_H20). For all the variables, the effects from sources of P were evaluated by tests of means and the effects from doses were evaluated by regression analysis. The mass of RP_EFL was lower than RP_FRW, but both variables followed the increases in the doses of the fertilizers. For all the fertilizers, the dry matter and the height of the maize plants followed the increases in the mass of the RP_EFL and RP_FRW. The RP_EFL from all the fertilizers had the greatest effect on the dry matter production of the maize plants. The P_H20, P_NAC and P_Total detected in the residues of fertilizers (RP_FRW) declined to levels lower than verified in the initial contents of the fertilizers. The largest decline was in the P_H20.