Nitrogen Fertilizer and Panicle Removal in Sweet Sorghum Production: Effect on Biomass, Juice Yield and Soluble Sugar Content

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 ˚Brix, 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 ˚Brix, sucrose and total sugar content in all varieties. Across the two years of study, panicle removal increased ˚Brix 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.

Fruit and Juice Metric Characteristics of Two Yellow Passion Fruit (Passiflora edulis Degener) Genotypes Grown in Southeastern Nigeria

“…These complementary advantages of combining organic and inorganic fertilizers enhanced better absorption of nutrients and their utilization for higher juice production among other fruit metric traits. The present study corroborates with previous reports indicating that increased fertilizer rate increased juice volume and percentage of passion fruit (Ani and Baiyeri, 2008), kinnow mandarin (Garhwal et al, 2014) and sweet sorghum (Kering et al, 2017).…”

Optimizing Bioethanol (C2H5OH) Yield of Sweet Sorghum Varieties in a Semi-Arid Environment: The Impact of Deheading and Deficit Irrigation

“…The augmented sugar content and juice yield may be linked to stalk thickening, facilitating greater juice accumulation. Similar results were reported by Rajendran et al [48] and Kering et al [49], indicating that deheading during anthesis substantially enhances productive tiller count, main stalk width (by 20%), juice output (by 30%), and sugar yield (by 10%), albeit at a slight reduction in Brix concentration, sucrose content, and juice purity (approximately 5%). Zhao et al [47] recommend harvesting sweet sorghum hybrids around 20 days post-anthesis, increasing stalk dry yield and estimated ethanol yield significantly.…”

Evaluation of Bioethanol Yield Potential of Different Sweet Sorghum Cultivars Grown as a Second Crop Under Eastern Mediterranean Conditions

“…Brix degrees varied from 19.93 to 10.50 •Bx in the study. These results were considerably higher than those reported in semi-arid tropics [14] central Missouri, USA [12], Nebraska, USA [15], and Virginia, USA [16]. The highest brix degree was obtained from Red's Red followed by ICSV 700 with slight difference, while Gülşeker attained the lowest value.…”