كليدواژه :
زمان برداشت , Forage sorghum , Different harvesting dates , كشاورزي , سورگوم علوفه اي , قابليت هضم , پروتيين خام , Dry matter digestibility , crude protein
چكيده لاتين :
The effect of different harvesting dates on nutritive value of forage sorghum cultivars was studied in a Randomised Complete Block Design with factorial arrangement of 15 treatments and four replications at Experimental Station, College of Agriculture, Ferdowsi University of Mashhad. The three cultivars of forage sorghum were Ghalami Tabasi (a native cultivar), F1104 and Speed Feed. The harvesting dates were beginning of flowering, one week, two, three, and four weeks after beginning of flowering. The investigated plant characteristics were: plant height, number of tiller per plant, dry matter yield, forage yield components (percentage of leaf, stem and inflorescence), in vitro dry matter digestibility and crude protein content. Results indicated that there were significant differences between different cultivars in terms of plant height, number of tillers per plant, percentage of stem in dry matter, crude protein as well as dry matter digestibility. Percentage of leaf decreased by delaying the harvesting date for the first cut, but by delaying harvesting, the percentage of stem and inflorescence increased. Crude protein content decreased with delay in harvesting dates. There was no significant difference between different harvesting dates in terms of dry matter digestibility. Speed Feed cultivars had the highest total digestible dry matter yield in comparison with the other. Simulated model was indicative of the fact that plant height, number of tiller per plant and percentage of leaf were the main variables controlling dry matter digestibility in different sorghum varieties.
