Effect of Harvesting Time on the Chemical Composition of Pennisetum clandestinum

The study of the chemical composition of Pennisetum clandestinum at various harvesting time was carried out between March 2015 and March 2016 at the University of Dschang. A completely randomized block design comparing three harvesting frequencies (30, 45 and 60 days of growth) in 8 replicates on 96 plots of 4 m 2 (2m x 2m) each one, for a total of 24 plots per block, was used for the production of P. clandestinum. Consecutive harvests at each frequency were done throughout the farming season (March-November 2015). Samples of forage at each mow were collected for chemical analysis. The results showed that, from the first to the last mow of each frequency, dry matter (DM) and organic matter (OM) contents increased; the ash, crude protein (CP) and lipid contents decreased; while the cell walls (NDF), cellulose and hemicellulose contents varied in a zigzag way (except for hemicellulose at 60 days frequency). The mean chemical composition at each frequency showed that CP content decreased (p<0.05), cell walls content increased (p<0.05) with increasing cutting age while the highest lipid content (2.78 %) was obtained at the 45 days frequency. The mean chemical composition at 45 days frequency appeared better balanced: it was comparable (p>0.05) to the 30 days frequency for the highest CP and lipid content, and to the 60 days frequency for the highest cell walls content. Therefore, the 45 days re growth age should constitute the suitable harvesting frequency of P. clandestinum for its best chemical composition as fodder crop.

Keywords: Chemical composition, Cutting frequency, Harvesting time, Pennisetum clandestinum.