Response of vegetation and soil chemical characteristics to different grazing intensities in steppe rangelands of Nodushan, Yazd province, Iran

From the perspective of rangeland ecology، awareness of the effects of livestock grazing on the changes of structure، plant vegetation and soil characteristics is essential. The aim of this study was to determine the effect of different grazing intensities including heavy (0-200 m distance from water point)، moderate grazing (200- 800 m) and light grazing (800-1200 m) intensities on vegetation indices and soil characteristics in Nodushan region، Yazd province of Iran. For this purpose، plant vegetation cover and composition were recorded under three grazing intensities. Soil was sampled from depths of 0-30 cm. Data were analyzed by one way ANOVA، t-testandordination method (CCA) to assess the vegetation response in different grazing intensities. Results showed that plant species such as Astragalus achrochlarus، Salsola arbusculata and Tragopogon sp. were found in light grazing area. Allysum minus، Artemisia sieberi، Poa sinacia، Iris songarica، Lactuca glacifolia and Stipa barbata were identified in moderate grazing area. Eryngium sp.، Cousinia desertii، Bromus tectorum and Peganum harmala were the major species in heavy grazing area. Soil properties including N، P، K، OC، EC and pH were measured. According to the results، nitrogen and soil organic matter were decreased by increasing grazing intensities but P، K، EC and pH were increased. Since grazing pressure causes damage to vegetation and some soil properties، a moderate grazing is recommended for sustainable utilization of rangelands.