Potential Impacts of Water Stress on Rice Biomass Composition and Feedstock Availability for Bioenergy Production

Bioenergy from rice biomass feedstock is considered one of the potential clean energy resources and several small biomass-based powerplants have been established in rice-growing areas of Thailand. Rice production is significantly affected by drought occurrence which results in declined biomass production and quality. The impact of water stress (WS) was evaluated on six rice cultivars for biomass quality, production and bioenergy potential. Rice cultivars were experimented on in the field under well-watered (WW) and WS conditions. Data for biomass contributing parameters were collected at harvest whereas rice biomass samples were analyzed for proximate and lignocellulosic contents. Results indicated that WS negatively influenced crop performance resulting in 11-41% declined biomass yield (BY). Stability assessment indicated that cultivars Hom Pathum and Dum Ja were stress-tolerant as they exhibited smaller reductions by 11% in their BY under WS. Statistics for proximate components indicated a significant negative impact influencing biomass quality as ash contents of Hom Chan, Dum Ja and RD-15 were increased by 4-29%. Lignocellulosic analysis indicated, an increase in lignin contents of Hom Nang Kaew, Hom Pathum, Dum Ja and RD-15 ranging 7-39%. Reduced biomass production resulted in a 10-42% reduction in bioenergy potential (E). Results proved that cultivation of stress-susceptible cultivars or farmer's choice and occurrence of WS during crop growth will reduce biomass production, biomass feedstock availability to biomass-based powerplants and affect powerplant's conversion efficiency resulting in declined bioenergy production.