Most of the time intensive grazing affects the lands either its vegetation or soil. This research aimed at determination of the exclosure, i.e. grazing ceased, effect on characteristics of vegetation and soil. Study area is located on northeast rangelands of Delfan County, Lorestan province. For this purpose, 120 quadrates of 1*1 m² in a randomized-systematic method of sampling were put along 12 transects of 100 m long. In each quadrate, the list, density, the percentage of canopy cover of the species were recorded in addition, litter, stone and gravel, and bare soil were measured and recorded. Soil samples from the beginning, middle and end of each transect were taken from a depth of 0-30 cm in the exclosure and under grazing areas (36 samples in each area). Samples were taken to the laboratory and some soil characteristics including organic matter, potassium, phosphorus, electrical conductivity, Acidity and percentage of clay, silt and sand were determined. Independent t-test was used to compare the mean of the studied factors of both areas, in the SPSS18 environment. Principal component analysis (PCA) was used to determine the most important variables affecting exclosure and grazing areas. According to the results, 132 species were identified, belonging to 30 families and 104 genera, of which 124 and 108 species were recorded in the rangelands under exclosure and grazing conditions, respectively. The canopy cover percentage of perennial grasses and forbs as well as litter percentage was higher inside the exclosure. The canopy cover percentage of annual grasses and shrubs as well as bare soil percentage was lower in comparison to outside of the exclosure. The density of perennial grasses and forbs increased, while the density of shrubs decreased inside the exclosure (P<0.01). In addition, a higher production and percentage of palatable plants was obtained from the rangeland under exclosure condition. In the exclosure area, the percentage of organic matter, nitrogen, phosphorus and potassium is higher than the grazing area (P<0.01) and the electrical conductivity is lower than the grazing area (P<0.05). Results of principal component analysis showed that organic matter, nitrogen, phosphorus, potassium and electrical conductivity had the most influence on vegetation characteristics of exclosure and under grazing areas.

Keywords: Exclosure, Production, Vegetation, soil characteristics, Delfan County.

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