BIOCHAR NA FERTILIDADE DO SOLO, MORFOMETRIA E PRODUÇÃO DE CAPIM ELEFANTE

Abstract

Among the many forage species used in ruminant feeding, elephant grass (Pennisetum purpureum Schum.) plays a prominent role for being perennial and of high dry matter production potential. The increase in soil fertility associated with irrigation in the Cerrado (Brazilian Savannah) is shown as strategies for increasing animal production fed with elephant grass. This paper aimed to evaluate the elephant grass cultivar performance and the soil chemical characteristics under biochar doses of 0, 8, 16, and 24 t ha-1. The treatments were arranged in a randomized block design in a factorial scheme of 2 cultivars x 4 biochar doses and were analyzed in a split plot; the plots, cultivars x doses, and split plots in 4 replicates were evaluated 4 times. The factor season was not considered for soil fertility. attributes evaluated were: (a) stem diameter (SD); (b) plant height (PH); (c) number of tillers (NT); (d) number of leaves (NL); (e) pre-dry mass at 65 °C (PDM65°); (f) dry matter content (DMC); (g) green leaf yield (GLY); (h) green mass yield (GMY); (i) dry mass yield (DMY); (j) leaf/stem ratio (L/S); (k) crude protein (CP); (l) pH, soil organic matter (SOM); (m) calcium (Ca); (n) magnesium (Mg); (o) potential acidity (H+Al); (p) cation exchange capacity (CEC); (q) potassium (K); (r) phosphorus (P); (s) base saturation (BS); and (t) aluminum saturation (AS). Significant effects were found for isolated factors and cultivar x season interaction for many growth and yield attributes with cubic and quadratic adjustments; for cultivar x dose interaction, only plant height was significant. No significant attributes were found for cultivar x dose x season. In the evaluations at the 225th (2nd) and the 335th (3rd) days after biochar application, there was better performance of the cultivars. Biochar doses did not significantly increase the cultivars’ morphometric and yield attributes. There was a tendency to increase the number of tillers and L/S ratio with the increase in biochar doses in BRS Kurumi cultivar. There were correlations between growth/yield and soil variables in both cultivars. The season factor response after biochar application depends on the cultivar and indicates greater climate effect. The biochar application does not improve the yield and crude protein variables of elephant grass cultivars under this study conditions. The biochar studied showed lower results than expected, suggesting better study with longer reaction time with the soil.