Effects of inter-cutting interval on biomass yield, growth components and chemical composition of napiergrass (Pennisetum purpureum Schumach) cultivars as bioenergy crops in Thailand

Abstract

The effects of inter-cutting interval on biomass yield, growth components and chemical composition of napiergrass (Pennisetum purpureum Schumach) as a source of bioenergy was investigated over 1 year in Thailand. Five cutting intervals (1-, 2-, 3-, 6- and 12-monthly) were examined on three napiergrass cultivars (Bana [hybrid with pearl millet], Common [normal type] and Muaklek [dwarf type]). Peak biomass yield occurred in all cultivars with 3-month inter-cutting interval, with a mean of 50.2 t dry matter (DM) ha−1 year−1 averaged across cultivars, while a 6-month interval produced 46.2 t DM ha−1 year−1. Although cellulose concentration increased as inter-cutting interval increased, energy concentration in the harvested material also peaked with 3-monthly cutting. Both Common and Bana were superior to Muaklek in terms of DM production. Further studies are needed to refine harvesting frequency in different seasons to maximize biomass yields while ensuring cash flow and minimizing harvesting costs.