Lime and phosphate application as mycorrhizae stimulation to enhance growth and yield of Marandu grass

Abstract

Pastures are important food sources for Brazilian cattle herds. However, inadequate management of soil fertility has emerged as a major cause of low yield rates and of progressive degradation of these areas. The objective of the present study was to evaluate growth, by means of morphogenetic and structural characteristics, and yield of Brachiaria brizantha Stapf. cv. Marandu as functions of the application of the mycorrhizae stimulant formononetin, associated with lime and phosphate application. The experimental design was completely randomised with four replications, and the treatments were arranged in a 2 x 2 x 5 factorial scheme, consisting of two liming treatments (with and without limestone), two formononetin treatments (with and without application) and five P2O5 doses (0, 25, 50, 100 and 200 mg dm-3). Three shoot cuttings were carried out after a first standardisation cutting to evaluate the morphogenetic and structural characteristics as well as the dry matter yield of different morphological fractions. Liming and phosphate application at the dose of 141 mg dm-3 P2O5 increased growth and yield of Marandu grass, and these practices are essential for the cultivation of this pasture grass in Yellow Latosol of the Cerrado region of Piauí, Brazil. The application of formononetin increased stem elongation rate, total number of tillers and green stem dry matter, and decreased dead dry matter of Marandu grass, which are effects that contribute to the improvement of pasture quality.