Abstract
Alternative and renewable bio-based energy sources are gaining prominence worldwide. Sweet sorghum is currently being evaluated throughout the world because its stem juices are rich in sugars that can be directly fermented to ethanol. In this two-year study, sweet sorghum varieties; Dale, Theis, Topper 76-6, and M81E (Obtained from Mississippi State University Experiment Station, MS) and CHR-SW8 (Obtained from Chromatin Inc., IL) were used. Nitrogen (N) fertilizer rates of 0, 40, 80 or 120 kg·N·ha-1 were applied to experimental units. The experiment was a randomized complete block design with treatments in a split-split plot arrangement with three replications. Nitrogen rate was the main plot, cultivar as sub-plot, and panicle removal as sub-plot. Results showed that N application increased fresh stem yield, juice volume, but had minimal effect on juice soluble sugar concentration. Compared to controls, application of ≥40 kg·N·ha-1 increased fresh yield and juice by >60% and 10%, respectively. There were also variety differences in harvested fresh biomass, juice volume and oBrix, and soluble sugar content. Dale and Theis consistently showed lower sucrose compared to other varieties over the two years. Panicle removal during early reproductive phase increased oBrix, sucrose and total sugar content in all varieties. Across the two years of study, panicle removal increased oBrix by more than 10%, sucrose and total sugar increased by more than 20%. Selection of varieties that produce high juice volume with high sugar content and strategies to inhibit seed formation may result in improved juice quality.
Highlights
Sweet sorghum is currently being evaluated throughout the world because its stem juices are rich in sugars that can be directly fermented to ethanol
Results showed that N application increased fresh stem yield, juice volume, but had minimal effect on juice soluble sugar concentration
Across the two years of study, panicle removal increasedBrix by more than 10%, sucrose and total sugar increased by more than 20%
Summary
Sweet sorghum whose stems contain high content of fermentable sugars [3] [4] [5] [6] is being evaluated, worldwide, as a source of sugar-rich juices for bio-ethanol production. Sweet sorghum is reported to produce 23% more fermentable sugars, requiring 37% less nitrogen (N) fertilizer, and 17% less irrigation water than maize [8]. Variety selection and field management approaches like de-heading affect stem sugar concentration [12] [13]. These differences in juice sugar concentration and juice volume may be responsible for reported variation in ethanol yields among sweet sorghum cultivars [9] [12] [14] [15]. Bagasse can be burned to provide heat and electrical energy [5] [17]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
