Growth analysis of Toledo grass Urochloa brizantha (Hochst. Ex A. Rich.) R.D. Webster in sub-humid warm climate

Abstract

Objective: Perform a growth analysis of Toledo grass (Urochloa brizantha CIAT 26110) during de rainy season, from sowing to 180 days, to determine the optimum harvesting moment. Design/methodology/approach: The morphological composition (CM), growth rate (GR), plant height, intercepted radiation (RI), leaf / stem ratio (L:S), leaf / non-leaf (L:NL), and biomass accumulation were evaluated every fifteen days during a 180 days period, except for the first two samples (monthly). Data were analyzed using the GLM procedure of SAS, under an experimental design of randomized blocks, with repeated measures over time, with three replicates.  Results: The CM varied significantly (P<0.01) through the different physiological states. The maximum production of aerial biomass (19.9 t DM ha^-1) and GR (131.9 kg DM ha^-1 day^-1) were reached 150 days after sowing (dap) and that of leaves (3.9 t DM ha^-1) was at 135 dap. At this time the RI was 100% and the height of plant was 106 cm. Limitations on study/implications: Toledo grass should be planted in the rainy season to be used when the canopy reaches a coverage greater than 80%, because the proportion of leaves decreases as the age of the plant progresses. Findings/conclusions: The highest accumulated total biomass, so it is suggested that the cut be made at 135 days after planting