Investigation of Phenological Stages and Harvest Year on Forage Quality of Rangeland Species in West

In this research, in order to determine the nutritional value of important vegetation species in certain climates, samples were selected from among 23 palatable and important plants that generally found in the ranges under consideration. The sampling was performed in two phonological stages in years 2004 and 2005. Then, the samples were chemically analyzed for the determination of their nitrogen and ADF content. The split plat method was used for the statistical analysis of data with respect to the arrangement of randomized complete block design in three replications of 46 treatments in each location. Plant species were taken as main factors and the growth stage was considered as the secondary factor and ranges played the role of replication. The characteristic studied was the forage quality (nutritional value) of the plants in various phonological stages in the course of two growth seasons. Following collecting data, in order to examine changes in forage quality of the species in various phonological stages and as well the mutual effects of the harvest year on the forage quality, the combined variance was analyzed using MSTAT-C software program and mean values were compared based on the Dunken test. Results show that chemical composition of the plants studied varies considerably and the phonological stage affects the forage quality significantly. Statistically, a significant difference between ADF content of the species in various phonological stages was not observed so that the study showed changes in a certain species in the years under consideration follow a single trend. The protein content of the species in different phonological stages of the harvest years also varied significantly.