The effects of cultivation methods and planting season on biomass yield of Napier grass (Pennisetum purpureum Schumach.) under rainfed conditions in the northeast region of Thailand

Abstract The worldwide search for carbon dioxide neutral biomass for the conversion into bio-energy as alternative to fossil fuels has promoted Napier grass for cropping in warm climates due to high yields even under less-than-ideal management. Our objectives were to evaluate the effects of cutting types (setts, 60-cm and 120-cm stem sections and terminal cuttings), planting methods of setts (vertical insertion or horizontal burial), and planting date (rainy or dry season) of Napier grass for dry matter yield (DMY) in a field experiment under low-fertile conditions carried out and repeated in two consecutive years in northeast region of Thailand. Terminal cuttings produced up to 16.14 Mg DM ha −1 and also showed the best planted-to-produced biomass ratio, followed by long stems but the setts produced the smallest yields. It was observed that the organogenesis of stem-section cuttings was slower than terminal cuttings which, consequently, produced more DMY. In fact, terminal cuttings appeared most suitable for the direct propagation in the field for the highest biomass production. Non-significant differences between DMY were observed between planting methods of vertical insertion or horizontal burial of setts as what prefers their handling in the field. Furthermore, an unclear pattern was found for the planting date of setts when more biomass was produced in the dry season from 2012 to 2013, and vice versa during second year of the experiment. Nevertheless, the non-significant differences of planting date showed that Napier grass could improve land-use efficiency and bear additional income, if cropped during the dry season.