Influence of variety, row type and time of sowing on the morphology, chemical composition and in vitro digestibility of barley straw

Abstract

SUMMARYLeaf proportions (LP) were determined in spring barley straws harvested at Cambridge in 1984 and 1985. Linear regression equations showed that a greater number of days to flowering increased LP whilst greater plant height decreased LP in spring barley straws. Plant height accounted for more than 70% of the variance in LP. By contrast, grain yield and stem diameter accounted for only a small percentage of the variance in LP. Straws from two-rowed winter barleys had slightly higher LP than six-rowed winter barleys but LP in winter and spring barleys were similar.Leaf blade and leaf sheath fractions of the straws had lower acid detergent fibre and lignin contents and were more digestible than the stem fractions. Linear regression equations of straw digestibility in spring barleys on LP, grain yields, days to flowering and plant heights showed that LP accounted for a higher percentage of the variance in digestibility in 1984 than the other characteristics. In 1985, when harvesting conditions were unusually wet, grain yield accounted for the highest percentage of the variance in straw digestibility.There were no differences in chemical composition and straw digestibility between two-rowed and six-rowed barleys, but winter barleys had higher straw digestibility than spring barleys. Date of sowing did not influence straw quality in two-rowed winter barleys.The ranking of two-rowed spring barleys for LP, chemical composition and digestibility suggested that varieties with consistently better straw quality could be identified.