CUTTING FREQUENCY IN CAYMAN GRASS (Urochloa HYBRID) ON THE CALORIFIC POWER OF THE MEXICAN WET TROPIC

The objective of this study was to evaluate the effect of cutting frequency in Cayman grass (Urochloa HYBRID) on biomass yield, moisture, ash, ethereal extract, neutral detergent fiber (FDN), acid detergent fiber (FDA), acid detergent lignin (LDA), crude protein (PC), calorific value, and theoretical bioethanol yield. Four cutting frequencies were established as treatments: 30, 60, 90, and 120 d, arranged in a completely randomized block design with three replications. Data were analyzed with GLM (SAS), and means were compared with the Tukey test (p ≤ 0.05). The highest biomass production (11.9 Mg ha-1 year-1), calorific value (15.1 MJ kg-1), and LDA (5.7 %) were obtained at the 120 d cutting frequency. The concentration of FDN (61.8 %), FDA (43.6 %), cellulose (38.1 %), and theoretical bioethanol production (218.4 L Mg-1 MS) were statistically different at the cutting frequency of 90 d. The values of hemicellulose (18. 7 %) and ethereal extract (1.8 %) were statistically different at the 60 d-cutting frequency; while PC (9.7 %) and ash (11.8 %) showed significant differences at the 30-d cutting frequency. Based on the biomass yield and calorific value of Cayman grass, it can be considered as a potential plant material for cellulosic ethanol production.