Author
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Venuto, Bradley |
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Submitted to: American Forage and Grassland Conference Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 1/20/2006 Publication Date: 3/10/2006 Citation: Venuto, B.C. 2006. Producing biomass from sorghum x sudangrass hybrids [abstract]. American Forage and Grassland Conference Proceedings, March 10-14, 2006, San Antonio, Texas. p. 34. Interpretive Summary: ABSTRACT ONLY Technical Abstract: Biomass may be derived from low-input systems, such as Conservation Reserve Program acreage and agricultural crop residue or it may be derived from dedicated cropping systems. Sorghum and sorghum x sudangrass hybrids can produce high forage yields and cultivars selected for biomass production are available. The objective of this study was to evaluate harvest strategies to maximize biomass production and extend the harvest interval. Three randomized replications of 25 sorghums and sorghum x sudangrass hybrids and ‘Piper’ sudangrass were seeded in May of 2004 and 2005 at El Reno, Oklahoma at 20 lbs per acre. Soil type was a Brewer silty clay loam. A mid June broadcast fertilizer application of 75 lbs of N per acre was made to all plots. Plot size was approximately 5 ft by 25 ft. Plots were divided into 5 ft by 10 ft sub-plots and two harvest treatments consisted of (1) a single late season harvest or (2) a late summer harvest followed by a ratoon harvest after first frost. Treatment 1 plots were harvested in late September and treatment 2 plots were harvested in early August and again in early November. Plant height and plant stem diameter (10 stems per plot) were measured at harvest. The number of stems per square foot, designated as ‘stem density’, was measured after harvest. Plant maturity was rated at the August and September harvests. Mean yield for treatments 1 and 2 were similar at 12.8 and 11.7 tons of dry matter (DM) per acre, respectively. However, harvest treatment 1 yields ranged from 7.3 to 21 tons of DM per acre and harvest treatment 2 yields ranged from 8.8 to 14.5 tons of DM per acre. No differences for year or year by entry interaction were observed for yield and plant height. However, entries and treatments differed and an entry by treatment interaction was observed. Stem diameter and stem density measurements differed across years, entries and treatments. A year by entry interaction was observed for these variables. Although correlations between yield and height, stem diameter and stem density (negative correlation) were observed, height was the strongest indirect indicator of yield with r = 0.68; P < 0.0001. Maturity did not correlate with mean harvest yield or stem density it but was positively correlated with stem diameter and negatively correlated with plant height. Maturity was negatively correlated with harvest treatments indicating an effect of maturity particularly on later season and re-growth performance. This research demonstrates the high biomass production available from sorghum and sorghum x sudan grass hybrids and the potential for matching cultivars with harvest management to provide maximum productivity over an extended harvest window. |
