Characteristics of phosphorus supply to sweet corn grown on a "cerrado" soil

Abstract

Phosphorus supply to sweet corn grown on a Red-Yellow Latosol was studied in two steps. In the first one, nine P levels ranging from 10 to 600 mg of P/kg of soil were applied to an untreated soil of Brazilian "cerrado", by mixing triple superphosphate. In the second experimental study, five P levels ranging from 10 to 500 mg of P/kg of soil were applied to each of the nine levels of the first phase, in a simulated furrow, in 5 liter pots. Plant growth and P uptake responses were related to aplied P for both treatments, by calculating regression equations for each step. The Y = a-bP+cP² equations relating P needed to obtain 90% maximum growth to phosphorus in the soil at each experiment of study two were fitted. These equations were calculated for three methods of P soil analysis: P in the soil solution, P extractable by double acid and P extracted by resin.