PHOSPHORUS SOURCES AND CORN GROWTH IN SOILS WITH DIFFERENT PHOSPHATE BUFFERING CAPACITIES

This study was carried out to evaluate, under greenhouse conditions, the efficiency of phosphate fertilizers on corn growth, in soils with different P buffering capacities: sandy Quartzarenic Neosol (NQ), loamy Red-Yellow Latosol (LVAm), and clayey Red-Yellow Latosol (LVAr). The experimental design was completely randomized with four replications, in a 2x4+8 factorial scheme. It was tested the combinations of two P Testing Sources (TS's 1 and 2) with four doses, and eight additional treatments: Testing Source 3 (TS3); triple superphosphate + calcitic limestone (SP+CL); SP + dolomitic limestone (SP+DL); the mixtures SP+TS1 and SP+TS2 in the ratio of 1: 1 based on total P2O5; magnesium thermophosphate (MT); Araxa rock phosphate (RP); and a check without P. The P doses were defined based on the remaining-P analysis, being different for each soil, and applied according to the total P2O5 content of the respective fertilizers. The dry matter production, the content and accumulation of P, and P use efficiency (PUE) in each treatment were evaluated. TS's had similar performance in relation to SP and MT on the corn growth. The PUE was modulated by the P capacity factor in the most buffered soils, LVAm and LVAr, being influenced by the P sources only in the NQ soil.