EFFECTS OF FERTILIZATION PROTOCOLS ON THE MORPHOLOGICAL AND PRODUCTIVE CHARACTERISTICS OF Brachiaria Brizantha CV. MARANDU

Abstract

The objective of this study was to evaluate the morphogenic and productive characteristics and water use efficiency of Brachiaria brizantha cv. Marandu in the presence and absence of liming, under different fertilization protocols. The experiment was carried out in a greenhouse, at the State University of Southwest Bahia, Campus "Juvino Oliveira", in Itapetinga, BA, between March and June 2023, and was organized in a completely randomized design, with four replications, in a 2 x 5 factorial scheme, composed of the presence or absence of liming and different dosages of NPK (0, 50,  100, 150 and 200%, on the 100% recommendation of the Fifth Approximation - Recommendations for the use of correctives and fertilizers in Minas Gerais), evaluated during two periods of 28 days. Fertilization boosted the development of morphogenic and productive characteristics of the plants. The leaf appearance rate and the phyllochron showed quadratic behavior, with optimal points at 173.6% and 153.8% of the dose, respectively. The leaf elongation rate, the SPAD index, the number of tillers, and the biomass production showed increasing linear responses to fertilization, with increases proportional to the doses applied. Total dry mass and root dry mass also showed a linear increase, while root volume and water use efficiency showed quadratic behaviors, with optimal points in 222.2% and 181.3% of fertilization, respectively. Thus, doses higher than 150% of NPK favor plant development, even without liming, optimizing productivity and water efficiency.