Estimation of long-term pasture production using important factors of climate and soil characteristics on forage production is inevitable. Reduced water and precipitation is important factor limiting production of fodder, especially in arid and semi-arid areas. Water use efficiency in these areas is the amount of water stored in the root orientation early in the growing season and water spread area of effective rainfall in the growing season that is used for evaporation and transpiration in plants. One of the important sections of the hydrological cycle is evapotranspiration. The transpiration directly affects forage production. The basis of estimating the water requirement of plants is the potential evapotranspiration which can be calculated by different methods. In this study, forage production in steppe rangelands of Dehsir, Yazd province, Iran were estimated using climatic index of potential and actual evapotranspiration and soil characteristics using Penman-Montith (Cropwat 8.0 software). The climatic data were provided from Dehshir Rainfall and Abarkooh Synoptic Station. Soil samples were taken by Auger at the beginning period of the growing season and soil moisture content was obtained weighing the soil before and after drying to constant weight in oven (100°C) in 2013. Then the regression model for estimation of forage production using soil moisture and evapotranspiration as independent variables was developed. The results showed that forage production had a strong correlation with the climatic index of actual evapotranspiration according to the estimation of actual evapotranspiration in a ten-year period, a model was provided for forage production as Ya=194.85+1.132(ETact). It could be said that actual evapotranspiration as an index for climate yield is one of the fundamental factors in estimating forage production. تفاصيل المقالة

This study was conducted to evaluate the effect of copper extraction on the structure and function of rangelands ecosystem around the mine area in Dareh Zereshk, Yazd province, Iran. Three study sites were considered at the specified intervals of the mine (0-200, 200-500 and 500-1000m). This research was conducted from 2012 to 2013. In each location, three linear transects with a length of 50 m were deployed in the slope direction. The structural characteristics were measured for ecological patches and inter patches space along each transect, and the landscape organization indices for each ecological unit (distance from the mine) were calculated. For each patch and inter patch, five measurement areas (replicates) were considered over each transect. In addition, 11 soil surface indices were evaluated and categorized. Using the soil surface indices scoring, the functional characteristics of each ecological unit including stability, permeability and nutrient cycle were calculated for each patch and inter patch in three locations. Based on the results, there were significant differences between the nearest (0-200m) and far (500-1000m) ones from the mine for indicator and functional traits (P<0.05). But there was no significant difference between the mid distance of the mine (200-500m) and two other sites, near and far from the mine (P>0.05). On the other hand, the function of different types of ecological patches was significant at different distances from the mine (P<0.05). So, the combined patches and inter patches had the highest and lowest values of functional indicators, respectively. The results demonstrate the efficiency of the landscape function analysis method to assess the post-mining damages and any subsequent reconstruction of rangeland in the around area. تفاصيل المقالة