Doses of Phosphorus in Monoammonium Phosphate form Incorporated in Biodegradable Polymers for Corn

The use of monoammonium phosphate (MAP) dissolved in organic polymers can reduce the fixation of phosphorus in the soil, and thus provide greater availability of this nutrient for long-term crops. The objective of this study was to evaluate the effect of doses of phosphorus in conventional form and incorporated MAP in biodegradable polymers, evaluating nutritional status, production components and corn grain yield, as well as the residual effect of P and N. The experiment was conducted in a no- tillage system consolidated for more than 10 years in a Latossolo Vermelho distrófico (Oxisol) with a clay texture located in Selvíria, MS, Brazil. The experimental design was a randomized block design with four replicates, arranged in a 4 × 4 factorial scheme, four forms of MAP (conventional, P1 = polymers with 30% MAP + water, P2 = polymers with 70% MAP + water and P3 = polymers with 30% of MAP), and four doses of P2O5 (0, 60, 120 and 180 kg ha-1), applied soon after emergence of the seedlings in the corn sowing line. Polymer P1 released higher amounts of P to the soil up to the R1 stage of corn, also provided the highest grain yield, indicating to be the most promising for use in Brazilian Cerrado soil.