Performance of a mixed mineral fertilizer produced from sedimentary natural phosphate

Abstract

The objective of this work was to evaluate the agronomic efficiency of a mixed mineral fertilizer produced with sedimentary natural phosphate added with limestone and sulfur sludge, compared with the simple superphosphate fertilizer. The experiment was carried out in a greenhouse and three successive crops were carried out in the following sequence: corn, beans, corn. The plants were grown in plastic pots containing 3 kg of soil classified as Red-Yellow Latosol. The experimental design was in randomized blocks, in a factorial scheme, with two phosphate fertilizers (simple superphosphate - SSP and mixed mineral fertilizer - MMF), four doses of P₂O₅ (25, 50, 100 and 150 mg of P₂O₅ dm^-3), two conditions (soil incubated with limestone and not incubated) in addition to two controls, without application of P. The shoot dry matter production (MSPA), the shoot phosphorus accumulation (APPA) and the available phosphorus concentration were evaluated in the soil after each cultivation. The results showed that SSP was more efficient than MMF in the production of dry mass and in the accumulation of P. The greatest responses of MSPA and APPA in relation to the increase in the dose of MMF were observed in LVA not incubated with limestone. The mixed mineral fertilizer provided higher values ​​of P available in the soil after the three crops compared to the SSP.