Biomass production and stability of five energycane cultivars at two latitudes in Georgia, USA

Authors: Knoll, Joseph - Joe; Anderson, William - Bill; MISSAOUI, ALI - University Of Georgia; Hale, Anna; HANNA, WAYNE - University Of Georgia

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2021
Publication Date: 3/4/2021
Citation: Knoll, J.E., Anderson, W.F., Missaoui, A., Hale, A.L., Hanna, W.W. 2021. Biomass production and stability of five energycane cultivars at two latitudes in Georgia, USA. Agrosystems, Geosciences & Environment. 4:e20146. https://doi.org/10.1002/agg2.20146.
DOI: https://doi.org/10.1002/agg2.20146

Interpretive Summary: Energycane is a tall perennial grass that is related to sugarcane, but it has lower sugar content and greater cold tolerance than sugarcane. Energycane has been considered as a viable bioenergy crop for the Southeast USA. Five energycane cultivars were tested at a northern (Athens, GA) and a southern (Tifton, GA) site for seven years. Test plots were planted during the fall of 2008 and were grown under rainfed conditions with recommended fertilizer applied in the early spring each year. Plant height was recorded at least monthly, and stalks were sampled to determine juice and sugar content at harvest. Whole plots were mechanically harvested after killing frost each year and weighed to determine biomass yields. A strong correlation was observed between biomass yield and mature plant height, while sugar yields and biomass yields were not strongly correlated. Averaged across years and locations, the greatest biomass yields were produced by cultivars Ho 06-9001 (27.04 Mg/ha) and Ho 06-9002 (25.11 Mg/ha). Average biomass yields peaked in year four at Tifton (39.75 Mg/ha) and year five at Athens (30.52 Mg/ha), but local weather conditions appeared to have a greater influence on yields than stand age. Day-long freezes during the winter and late spring freezes after shoot emergence resulted in reduced growth rate and yields in subsequent growing seasons. These cold weather events were more common at Athens than Tifton, resulting in yields being more variable at the northern location.

Technical Abstract: Energycane (Saccharum hyb.) could be a viable bioenergy crop for the Southeast USA. Five energycane cultivars were planted in 2008 at a northern (Athens, GA) and a southern (Tifton, GA) site, and were grown for seven years to compare biomass and sugar yields. Plots were arranged in a four replicate randomized complete block design at each site. Energycane was grown under rainfed conditions with ample fertilizer such that nutrients would not be limiting. Plant height was recorded at least monthly, and stalks were sampled to determine juice content and Brix (an estimate of sugar content) at harvest. Whole plots were mechanically harvested each year after killing freeze and weighed to determine biomass yields. A strong correlation (r = 0.785) was observed between biomass yield and mature plant height, while the correlation between biomass and sugar yields was low (r = 0.271). On average, the greatest biomass yields were produced by cultivars Ho 06-9001 (27.04 Mg ha-1) and Ho 06-9002 (25.11 Mg ha-1). Sugar yields were generally low, averaging only 609 kg ha-1. Biomass yields peaked in year four at Tifton (39.75 Mg ha-1) and year five at Athens (30.52 Mg ha-1), but local weather conditions had a greater influence on yields than stand age. Day-long freezes during the winter and late spring freezes after shoot emergence resulted in reduced growth rate and yields in subsequent growing seasons. These cold weather events were more common at Athens than Tifton, resulting in yields being more variable at the northern location.