The effect of different grazing gradient on density and production of Sage-brush in different distances from critical spots in Moghan plain

Villages are from the most effective factors that influence grazing distribution in rangelands. where other limiting factors such as slope, height and soil have no variation, forage utilization by livestock is Limited by distance from watering points. This study aimed to investigate the effect of grazing pressure and distance from the center of Crisis (village) on the characteristics of sage brush such as, percentage of vegetation canopy cover, species density and Production in three center of the crisis including: Panjaloo, and Coolash, Toolkloo. after reconnaissance field visit Of the study area in each of the crisis center sampling was conducted based on three distances from the village. The first site is located about 350-450 meters from the center of the crisis (village), the second site, 275-375 Meters from the first site and the third site was located 650-750 meters from the first site. at each site, samples collected based on systematic attempt to establish transects along the each transect with 10 plot with the size of 1 square meters,with a distanceof 10 meters from each other. In each plot , nominationed percentage of Vegetation canopy cover, species density and production were recorded. In each plot the parameters of species Composition and density, the canopy cover of each species, litter, bare soil and stone and gravel was recorded. Soil samples from a depth of 0 to 30 cm in the plots of first, fifth and tenth of each transect was collected as the One sample. the soil parameters such as pH, electrical conductivity, sodium, magnesium, calcium, potassium, Lime, phosphorus, organic carbon, organic matter and the percentages of sand, silt and clay was measured. One-Way analysis of variance and Duncan test were used for testing of all parameter means equality and grouping of Respectively. According to the results, in panjaloo production of sagebrush in different distances were Significant (P<0.01). Also results showed in both Koolash and Toolkloo, species density in different distances Were significant (P<0.01). but in three villages totally, distance from village had not significant impact on Sagebrush characteristics.In the second step, multivariate analysis such as the cluster analysis, factor analysis, Principal components analysis (PCA) were conducted using SPSS16 and Minitab17. By considering cluster Analysis result from 9 site show that classified in differen groups.results of factor analysis and PCAwere not Support the hypothesis. The results of clustering by Vard and PCA showed in addition with grazing intensity, Different environmental factors had effect on sagebrush characteristics. to survey of grazing gradient using one species is not suitable but, presence of different vegetation forms and Stone, latter, bare soil, canopy cover percentage approve presence of grazing gradient in moghan flat. Based on results our firs hypothesis was rejected because of ineffectiveness of different density of grazing on sage brush characteristics but the second hypothesis, changes in soil physical-chemical characteristics in different density of grazing , was accepted.