World Applied Sciences Journal 20 (2): 205-212, 2012 ISSN 1818-4952 © IDOSI Publications, 2012 DOI: 10.5829/idosi.wasj.2012.20.02.1624 Corresponding Author: Sedigheh Zarekia, Department of Range Management, Science and Research Branch, Islamic Azad University, Tehran, Iran. 205 Grazing Effects on Some of the Physical and Chemical Properties of Soil Sedigheh Zarekia, Mohammad Jafari, Hossein Arzani, 1 2 2 Seyyed Akbar Javadi and Ali Ashraf Jafari 1 3 Department of Range Management, Science and Research Branch, 1 Islamic Azad University, Tehran, Iran Faculty of Natural Resources, Tehran University, Tehran, Iran 2 Gene Bank Research Division, Research Institute of Forests and Rangelands, Tehran, Iran 3 Abstract: This paper studies short-term effects of grazing management on some of the physical and chemical characteristics of soil in steppe rangelands of Saveh (Markazi Province of Iran). Thus, features such as phosphorus, potassium, nitrogen, organic carbon, electrical conductivity, acidity and soil bulk density have been studied within two projects of range management; the Nemati rangeland with a rest-rotation grazing system for 10 years (moderate grazing intensity) and the Shirali rangeland with continuous grazing during the year (severe grazing intensity). The obtained data was compared with that of a rangeland, which had been excluded for four years. Studies showed that elements such as phosphorus and potassium in the Shirali rangeland are more than the other two regions. However, nitrogen and organic carbon, pH and soil bulk density were not significantly different in these three areas. The results indicate that enclosure and rest-rotation grazing system with moderate grazing intensity leads to small changes in some of the physical and chemical characteristics of soil. Therefore, the effect of management on soil properties requires a longer time in the steppe rangelands. Key words: Grazing Soil physical and chemical properties Steppe rangelands Iran INTRODUCTION Based on studies on rangeland, an important and Rangelands, as the context for profound economical biomass by livestock and subsequently, a significant and social changes in Iranian Nomadic People's lives, impact on the rotation of the nutrients and their have undergone some stress during the past three absorption [3]. In addition to general effects of grazing on decades due to excessive grazing (three-time the legal plants, livestock have also other effects on rangeland that capacity). Destruction of rangelands has faced our subsequently effect on forage production. Generally, country with deep crisis [1]. Soil, one of the most nutrients in livestock's feces and urine are useful for important elements of rangeland ecosystems, is the forage growth, while trampling and selective grazing can source of food and moisture content for pasture plants. be destructive. Livestock feces and urine are potential Excessive grazing is one of the most significant factors sources of nitrogen, phosphorus, potassium, sulfur, causing rangeland degradation and typically, this magnesium and calcium for plants [4]. Distribution of soil degradation is effective on vegetation and soil. In general, nutrients in a pasture is affected by different factors the effect of grazing on pastures is considered to be in including parent material, vegetation communities, three processes: the loss of plants due to livestock slope, aspect, kind of livestock, differences in grazing foraging; soil and litter trampling; and deposition of distribution patterns and watering points [5, 6]. feces and urine. The effects of these processes are hardly Different results have been reported on the effects of distinguishable from each other [2]. different grazing intensities and systems on physical and obvious effect of grazing is the removal of above-ground