ADUBAÇÃO FOSFATADA EM SOJA EM AMBIENTE PROTEGIDO: DOSES E MODO DE APLICAÇÃO

Abstract

Is a great match fixing in soil types dystrophic, and this is coming from non-renewable natural resource, there must be a conscious use of this nutrient, thus ensuring a sustainable way of practicing agriculture. This study aimed to evaluate, under protected cultivation, the amount of phosphorus that provides the best soybean development, and compare the mode of application of phosphorus determines changes in aspects of plant development. The experiment was conducted in greenhouse of DSER/CCA/UFPB in Areia - PB. Was used as substrate material of the surface layer of a yellow Latosol texture sandy clay, sieved in a 2 mm mesh. Eight treatments were used, with a combination of four levels of phosphorus (0, 15, 30 and 75 mg dm-3) and two application modes (localized and uniformly distributed): T1 - 15 mg dm-3 of P2O5 applied located, T2 - 15 mg dm-3 of P2O5 applied evenly distributed, T3 - 30 mg dm-3 of P2O5 applied located, T4 - 30 mg dm-3 of P2O5 applied evenly distributed, T5 - 45 mg dm-3 of P2O5 applied located T6 - 75 mg dm-3 of P2O5 applied located T7 - 75 mg dm-3 of P2O5 applied evenly distributed, and T8 - 0 mg dm-3 of P2O5 (control), using the experimental design in blocks with eight treatments and five replications. 48 days after sowing, the following parameters were evaluated: stem diameter (DC), number of leaves (NL), plant height (PH), number of nodes (NN), dry matter production of shoots (PMSPA), production of root dry matter (PMSR) and dry matter production of nodules (PMSN). The stem diameter, number of leaves, number of nodules, dry weight of shoot, dry weight and root dry weight of nodules, whose data were adjusted to the quadratic model, getting the best performance for the doses of 62,25; 55,19; 51,18; 81,05; 47,32 and 52 mg dm-3, respectively. And the variable height showed a positive linear correlation, not reaching its stability.