تاثير شدت هاي گوناگون چراي دام بر مواد آلي ، نيتروژن ، فسفر و پتاسيم خاك

The Effects of Different Grazing Intensities on Nitrogen, Phosphorus, Potassium and Organic Matter in Step Rangelands

The present study has analyzed the effects of different grazing intensities on soil chemical properties including nitrogen, phosphorus, potassium and organic matter content in different conditions of reference area, key and critical areas located in Savojbolagh, Iran during 2004-2005. Data produced based on randomized complete block design plot. In this case, study area, time and depth of sampling were appropriated for main plots and sub-plots, respectively. Statistical analysis was done using SPSS version 12. If significant differences were found between treatments then Duncan test was used for comparison of means. According to the results, there were significant differences between NPK rates during two years. The rate of organic matter, nitrogen and phosphorus was increased in second year and the amount of potassium was decreased. Animal grazing significantly affected soil chemical characteristics in all areas (reference, key and critical). There were significant differences between content of nitrogen, phosphorus, and potassium in two years, during the grazing season and between the two depths.