Title: Sorghum bioenergy cropping systems: production potential and early indications of soil benefits under limited water Authors
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 6, 2013
Publication Date: March 6, 2013
Citation: Burow, G.B., Acosta Martinez, V., Cotton, J.E. 2013. Sorghum bioenergy cropping systems: production potential and early indications of soil benefits under limited water. Meeting Proceedings. Paper No. PS0801. Technical Abstract: A two year field study was conducted to evaluate biofuel production potential of two forage sorghum cultivars differing in brown midrib trait under non-irrigated and deficit irrigation conditions in the semiarid Southern High Plains of the U.S. Cultivar SP1990 (non-bmr = conventional cell wall composition) produced significantly more biomass (29-62%) than PS bmr (reduced lignin) under irrigated and non-irrigated conditions during both years. Irrigation resulted in 26-49% more biomass and 28-72% more EtOH production during both growing seasons, indicating deficit water conditions without irrigation. Reduced lignin content in PS bmr biomass resulted in more efficient conversion (54%) to ethanol (EtOH) during both years. When less water was available due to below average precipitation, both cultivars produced similar amounts of EtOH at each irrigation level supporting the key role of water in biofuel productivity and in determining its sustainability in the edges or periphery of the Ogallala Aquifer region. Accordingly, when more water was available due to above-average precipitation during the second growing season, higher biomass production of SP 1990 resulted in 28% higher EtOH production than PS bmr at both irrigation levels. Overall ethanol production ranged from 1,600 to 3,380 L ha-1 during both years of the study. This study indicates that biomass chemical composition and modification (lignin reduction) and yield potential are critical factors when selecting sorghum cultivars for use as biofuel feedstocks under marginal water-deficit conditions.