EFFECT OF DIFFERENT PHOSPHORUS SOURCES IN BRACHIARIA BRIZANTHA CV. MARANDU CULTIVATED IN TWO SOILS

Abstract

The experiment was carried out at the Soil Science Department of the Federal University of Lavras, with the objective to evaluate the effect of the furnishment of different phosphorus (P) sources, during the implantation of Bracharia brizantha in the accumulation of phosphorus (P), nitrogen (N) content and shoot’s dry matter production (SDMP). The forage was grown in two distinct soils, a clayey dystrophic Red Latosol (Oxisol- LVdf) and in a sandy Neosol (Entisol- NQ), for 180 days, in pots (3 dm3). Four different phosphorus sources were evaluated: triple superphosphate (TS - 46.1% total P2O5), Arad reactive phosphate (AR - 33. 1% total P2O5), Araxá natural phosphate (AN - 22.71% total P2O5), and a 1:1 ratio mixture TS/AR (1:1 total P2O5). Each P-source furnished 200 and 350 mg kg-1 of P2O5, for the NQ and LVdf soils, respectively, based on the each source’s P2O5 total content. The experimental design was a completely randomized in 4x2 scheme, with four replicates. Based on the nitrogen (N) complementary fertilization, applied after each cut, high shoot’s N content were found ranging from 1.32 to 2.6 g/kg for the LVdf soil and 1.01 to 2.82 g/kg for the NQ soil, such that values for crude protein ranged from 8.25 to 16.25% and 6.31 to 17.62% for the LVdf and NQ soils respectively. Soil’s distinct mineralogy influenced Braquiaria response to the different P sources furnished. Considering that the shoot’s dry matter production (SDMP) was higher in the NQ soil, and the total P accumulation after four cuts was higher in the LVdf soil. The use of P- sources of higher solubility promoted higher values for SDMP. High values for brachiaria N content were observed under the addition of low solubility P-sources such as, AR and AN. Growth and dry matter production were limited by the lack of phosphorus in the grass’s establishment. KEY-WORDS: Concentration, solubility, crude protein, forage, phosphate fertilization.