Introducing resistance species (Bromus tomentellus L. Festuca, ovina and Stipa hohenackeriana) against medium grazing intensity in Firoukooh

This research was aimed to determine the allowable use of Bromus tomentellus, Festuca ovina and Stipa hohenackeriana in Firouzkooh rangeland during 2006 to 2010. Treatments included different harvesting intensities of 25%, 50%, 75% and control, performed on 40 medium-sized individuals of each species. Data were analyzed in a split plot in time design by SAS software and means were compared using Duncan. Results showed that the effects of treatment, year, and interaction effect of year*treatment were significant at 1% level of significance. In addition, the results of mean comparisons showed that the reduced forage yield was under the influence of harvesting intensities. In this regard, S.hohenackeriana and B.tomentellus were sensitive to drought while F.ovina was resistant to drought and more affected by the harvesting intensity. Our results clearly showed that a harvesting intensity of 25% and control treatment had no impact on the yield of species, leading to the reduced forage yield of the mentioned species. Therefore, an allowable use of 50% is recommended.