Abstract
Studies were undertaken to investigate the effect of plant density on feeding value of sorghum. Three plant populations were constituted from 44.4, 11.1 and 3.7 plants/m^2 using commercial hybrid (Sudax). 1) The dry matter yield increased with increase of plant density, but tillers and dry matter of one plant decreased at flowering stage. 2) Plant proportions were varied with plant density and rind portion of stem increased with increase of plant density. 3) Cell wall constituents (CWC) and acid detergent lignin (ADL) contents of whole plants were increased with increase of plant density. 4) CWC hydrolysis was varied with plant portion. Pith of stem and leaf blade were the most hydrolytic portions. Rind of stem was the lowest hydrolytic portion. Variation in CWC hydrolysis and in vitro dry matter disappearance (IVDMD) of whole plant were observed among the different level of plant density. CWC hydrolysis and IVDMD were increased with decrease of plant density. Those differences of feeding values were depended on the variance of hydrolysis of pith of stem and leaf blade and their proportion rates. 5) Crop growth rate (CGR) increased with decrease of plant density at heading to flowering stage. At this period, digestible dry matter which dissolved by neutral detergent solution and cellulase increased with decrease of plant density. 6) Digestible dry matter production increased with increase of plant density and was influenced with its dry matter production. But there were almost no significant difference between high and middle plant density in flowering stage. Because the IVDMD of middle plant density was higher than that of high plant density.
