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

Abstract

Abstract Energycane (Saccharum hybrid) could be a viable bioenergy crop for the Southeast United States. Five energycane cultivars were planted in 2008 at a northern (Watkinsville, GA) and a southern (Tifton, GA) site, and were grown for 7 yr to compare biomass yields. Plots were arranged in a four replicate randomized complete block design at each site. Energycane was grown under rainfed conditions with 90–112 kg ha–1 N applied annually. Plant height was recorded at least monthly, and stalks were sampled to determine juice volume and Brix (estimate of sugar concentration) at harvest. Whole plots were mechanically harvested each year after killing freeze and weighed to determine biomass yields. Biomass yield and mature plant height were strongly correlated at both Tifton (r = .746) and Watkinsville (r = .727). Biomass yields peaked in Year 4 at Tifton (39.8 Mg ha–1) and Year 5 at Watkinsville (30.5 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 Watkinsville than Tifton, resulting in yields being more variable at the northern location. The greatest yielding cultivars were Ho 06‐9001 (27.0 Mg ha–1) and Ho 06‐9002 (25.1 Mg ha–1). Stability analysis revealed that these two cultivars responded positively to favorable environments in terms of biomass yield and plant height.