Performance evaluation of biomass sorghum in Hawaii and Texas

Authors: MEKI, MANYOWA - Texas Agrilife Research; OGOSHI, RICHARD - University Of Hawaii; Kiniry, James; CROW, SUSAN - University Of Hawaii; YOUKHANA, ADEL - University Of Hawaii; NAKAHATA, MAE - Hawaiian Commercial And Sugar Company; LITTLEJOHN, KERRIE - University Of Hawaii

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2017
Publication Date: 4/26/2017
Publication URL: https://handle.nal.usda.gov/10113/5672296
Citation: Meki, M.N., Ogoshi, R.M., Kiniry, J.R., Crow, S.E., Youkhana, A.H., Nakahata, M.H., Littlejohn, K. 2017. Performance evaluation of biomass sorghum in Hawaii and Texas. Industrial Crops and Products. 103:257-266.

Interpretive Summary: Since the 1970s the state of Hawaii (HI) has been aggressively seeking alternative and renewable energy resources to reduce its overdependence on imported oil. Of the available alternatives, fuels produced from biological raw materials are viewed favorably due to the tropical year-round growing season for the production of fast-growing biofuel feedstocks. Although biomass sorghum [Sorghum bicolor (L.) Moench] has been identified as a high yielding bioenergy feedstock crop on the continental USA, there is lack of conclusive data on its performance in HI. The objective of this study was to (i) determine the adaptability and productivity of two biomass sorghum varieties, and (ii) identify the associated crop parameter attributes and environmental factors for high biomass yields. Two parallel trials were conducted on Maui, HI and in Temple, TX. At Temple, the sorghum varieties responded as expected, growing to heights in excess of 3 m and producing average biomass yields of 37.4 Mg ha-1. The biomass sorghum varieties also had large leaf surface areas that captured more solar radiation which resulted in a faster plant growth rate. In Maui, and in sharp contrast to the results obtained at Temple both biomass sorghum varieties behaved like grain sorghums, flowering in approximately 90 days after planting. The varieties did not grow as tall as the ones in Texas and yields were drastically reduced. The study underscored the importance of not only choosing the right bioenergy crop species, but also the suitability of target environments, planting season and management practices.

Technical Abstract: Although biomass sorghum [Sorghum bicolor (L.) Moench] has been identified as a high yielding bioenergy feedstock crop on the continental USA, there is lack of conclusive data on its performance in HI. The objective of this study was to (i) determine the adaptability and productivity of two biomass sorghum cultivars, and (ii) identify the associated crop parameter attributes and environmental factors for high biomass yields. Two parallel trials were conducted on Maui, HI and in Temple, TX. At Temple, the sorghum cultivars responded as expected, growing to heights in excess of 3 m and producing average biomass yields of 37.4 Mg ha-1. The high leaf area indices (LAI, 7.8-9.8) intercepted over 90% incident photosynthetically active radiation (PAR) at LAI > 4, while the computed average light extinction coefficient (k) was 0.48. An average plant growth rate (PGR) of 189 kg dry biomass ha-1 day-1 was achieved, while the average radiation use efficiency (RUE) was 2.75 g MJ–1. In Maui, and in sharp contrast to the results obtained at Temple both sorghum cultivars behaved like photoperiod insensitive short day grain sorghums, flowering approximately 90 days after planting. Measured and derived traits responded poorly; total biomass yields were reduced by 76%, plant heights (< 2.5 m), LAI (average, 3.8), PGR prior to heading (average, 41 kg ha-1 day-1). The study underscored the importance of not only choosing the right bioenergy crop species, but also the suitability of target environments, planting season and management practices.