نشریه مرتع و آبخیزداری
سال شصت و ششم شماره 3 (پاییز 1392)

Rangelands are among the natural resources which have a considerable effect on environment and man’s life. Iranian rangelands mostly have poor condition and exhausted by intensive over grazing, should be utilized according to their ecological capability and land suitability. The main objective of this study is to evaluate ecological capability and land suitability of Gheshlagh dam’s watershed area-parcel A (In Kurdistan province, western Iran) to develop range management plan. Following data collection; determination of the important parameters for evaluation of rangelands environmental capability in the study area was carried out and then obtained parameters were given values based on Analytical Hierarchy Process (AHP) method. Finally, the obtained values were applied to the important parameters for evaluation of rangelands environmental capability according to technique for order performance by similarity to ideal solution (TOPSIS). The results approved that suitability of a land is classifiable for various types of land uses using MCDM methods. Also according to the results specified that the physical criteria of land have more effective than other parameters to develop range management plan. Moreover, land evaluation of study area showed that eastern parts of the watershed had higher suitability to develop range management plan.

Insurance industry is one of the effective factors of developing sustainable agriculture. Natural resources that are more pone to influence than other phenomenon such as: Drought, there are limited areas under insurance. From 86.4 million hectares of country Ranges, there are nearly 3 million hectares under insurance. Semnan province are compared to other areas has more Range insured. Therefore, in this research effective factors in accepting Range insurance by Semnanian's livestock have been investigated. This research is experimental and applied in the purpose also collected information and documents library. Desired statistical community is all Range man in the Semnan. Among this number of 147 persons using a random sampling as a statistical sample was selected for the 75 samples insurance range men receiver and 72 samples of range men were incompliant insurance. Logit model estimated results show that the class extension, the amount of range feed production, and to borrow the amount preserve and income are efficacious and the number of cattle is negative and significant in the acceptance of ranges insurance.

Forage is the main product of rangelands. So, determining its economic value as one of the main important nonmonetary functions can help managers to improve planning and optimal utilization management of rangelands. The main purpose of this study is to estimate the economic valuation of the forage of summer rangelands in Nour-roud watershed basin in Mazandaran province. Consequently, total forage production estimated by using double method in 12 unit works. According to the heterogeneity of range forages in terms of economic and lacking organized market for transaction, have been used barely and using Replacement Cost Method (RCM). In order to homogenize the value of all forage plants, Total Digestible Nutrients (TDN) of each plant multiplied to its forage product to calculate the nutrition value of forage per rangeland unit work. According to the specified T.D.N of barely, the equivalent weight of barely, identified for each range/ha in different price scenarios (guaranteed, international and farm prices), total value of forage production calculated based on barely price. Results showed that, Forage yield equivalent to barely was estimated 276.5 kg per ha of 89826.7 usable summer rangelands. Its economic value was equivalent to 713280 Rials per hectare. Also, its average annual economic value by 3 price senarios estimated, 64.6 Milyard Rials. This amount of economic value was equal to 718900 Rials per hectare of Nour-rud rangelands. Also, the estimated forage values are only 25 percentage of total economic value of rangeland ecosystem that has been exploited as natural bequest without any investment.

Parameters as interception, infiltration, water storage on surface holes and soil profile, evapotranspiration are factors of loss water in a watershed and avoid from changing of precipitation to runoff. In this study, by use of HEC-HMS model and comparison of results of different methods of precipitation loss evaluation (Initial and constant, Green & Ampt, SCS curve number, Deficit & Constant and Exponential loss) consider to various purpose function percent error in peak tried to classify the methods. In this way, based on every purpose function, the method with least percent difference of observed discharge to calculated discharge take place in first preference and other methods take place in next preferences. Result show that, Exponential loss method placed in first preference and it selected as optimum method for simulation of runoff and Green & Ampt, Initial and constant, SCS curve number, Deficit & Constant methods placed in next preferences respectively.

Land use change is one of the main factors in the process of changing the regime of flood in watersheds. Taleghan watershed has been subjected to many land use changes over years, which probably effects on flood characteristics of Taleghan River. In present study the effects of land use change on some parameters including peak flow, volume and flood base time, in part of Taleghan basin, was investigated by using Geographical Information System (GIS) and HEC-HMS model. Land use maps of 1987 and 2002 were prepared and integrated with soil hydrological groups and pasture conditions maps in GIS with the aim of providing of CN map. Then by using curve number and SCS unit hydrograph in sub basins and also Muskingum routing method, HEC-HMS model was calibrated and validated, for 10 incident rainfall - runoff views. Results of the simulation showed that due to the changes in land use (the reduction in the level of agricultural lands and increases in pasture areas), peak flow and flood volume in 2002 than in 1987 showed the average reduction of 46% and 34%, respectively. The evaluation of base time of flood showed no change in the parameter in flood hydrograph at the study period. On the whole the results showed that the trend of land use changes have the positive effect on reducing flood productions in study area.

The aim of this study preparation of the predicted soil maps by using kriging and Inverse Distance Weighting methods in east rangeland of Semnan. Sampling was done within each unit of sampling parallel transects and 1 vertical transect with 750m length. Soil samples were taken from 0-20 cm in starting and ending points of each transect. There were used kriging and Inverse Distance Weighting methods by Gs+ and GIS software to predict clay, sand, lime, EC and available moisture factors. For comparing these methods, cross validation were used by statistical parameters of MAE and MBE. Results showed that kriging method is better than Inverse Distance Weighting method in all factors except clay factor.

Soil erosion is a serious environmental problem in Vazroud watershed, which is located in the centre of the Mazandaran Province, Iran. Unfortunately, Vazroud watershed like most Iran watersheds don’t have recorded data and erosion and sedimentation gages to research, monitor and model soil erosion at large watershed. In order to assess the soil erosion risk, soil erosion modeling at the watershed scale are urgently needed to be undertaken. This study integrated the Revised Universal Soil Loss Equation (RUSLE) with a Geographic Information System (GIS) to estimate soil loss and identify the risk erosion areas in the Vazroud watershed. Multi-source (map-, space- and ground-based) datasets were used to obtain factors of RUSLE, and an integrated analysis was carried out in raster format of GIS and it was classified into five categories ranging from minimal risk to extreme erosion risk. Extensive field observations verify soil erosion risk map and total accuracy (90%) obtained. The soil erosion map was linked to land use, elevation and slope maps to explore the relationship between soil erosion and environmental factors and identify the areas of soil erosion risk. The slopes between 25 to 45 degree, the altitudes between 1180 to 2180 from sea level and bare lands have the high and extreme erosion risk in this study area. The results allow decision makers to implement management strategies to prioritization area and soil erosion reduction in Vazroud watershed. The integrated approach presented is relatively easy, fast, and straightforward, showing good potential for successful application in other areas.

Evaluation soil erosion is an important matter to protecting it from destroying in future due to the excessive use of the inherent capacity of soil and also improper management. Therefore, in this study land vulnerability related to water and wind erosion of Abyek for crops and pasture land has been evaluated, using Raizal model as one of the Microleis sub-models. Morphological and physical and chemical analysis data were obtained of studying and evaluating the 32 soil profiles. Agricultural - climatic and management information including temperature and precipitation data were collected from Bagh-e-Kosar climatological station for the last 17 years. To study the effect of climatic changes in the assessment of land area for the year 2080 AD (for 70 future year), the reports of International Panel on Climate Change (IPCC) allocated to West Asia have been used. Utilization types considered for evaluation, including wheat, corn, barley and alfalfa. The results obtained of Land vulnerability evaluation studies related to water and wind erosion using Raizal model part have been prepared as maps in the GIS environment. Information obtained from Land vulnerability models related to wind erosion for crops and pasture land, also implies vulnerability risk fora wide percent of the region lands under the current management, that the results evaluation of the proposed management methods express the improvement of destroying ability classes.

Runoff and sediment measurement is difficult in mountain watershed because of many different problems such as time and financial limitations. So using simulation model is necessary in this regard. Accuracy and precision evaluation of models for different watershed of Iran is necessary. The aim of this study was the evaluation of SWAT model efficiency in simulation of runoff and sediment yield in Chelchay watershed in Golestan province, Iran and also calibration and validation of SWAT. SUFI2 algorithm was used for calibration and validation. Nash-Sutcliff for calibration period (2001-2005) and validation period (2006-2009) for average daily discharge was 0.5 and 0.4 respectively and for sediment concentration was 0.71 and 0.92 that is good according to past research results. Because SWAT is complex and integrated model and can be used as a management tool in watershed management so it is suggested that it would be used for evaluation of management activities effects in Chelchay watershed.

In this study the effect of month, place and different years on the preferencevalue of Bromus tomentellus in semi-steppe region was studied. The preferencevalue of the Bromus tomentellus was studied in two years and four months in three sites as cheshme anjir (Fars), Badamstan (Zanjan) Firuzkuh (Tehran). To determine the preferencevalue of species the two methods of as preference index and timing method was used. To compare preferencevalue in different sites times the factorial completely randomized design was used. Mean comparison was performed using Duncan's Multiple Range Test at 5% level. And to compare two methods whit each other the T test was used. The results of preference index showed that sites were significant at 1% level. But the other factors were insignificant differences according to the results of timing method all the factors were insignificant. Comparison of two methods by T test showed that the two methods were different.

Soil erosion is undoubtedly one of the most important problems in natural areas and has a devastating impact on grassland ecosystems. The present study was conducted to assess the ability of Rangeland Hydrology and Erosion Model for estimating sediment yield on rangeland’s hill slopes in dry regions at Shahid Noori paired watershed of Kakhk. RHEM is a mathematical, distribution and physical model that is capable to simulate hydrological and erosional processes with climatic data and hill slope’s characteristics. Measuring of sediment yield performed on 18 erosion plots in both disturbed and undisturbed rangeland conditions. In order to implement the model, the parameters of climate, soil texture, slope length, slope steepness, canopy cover and ground cover were measured and entered into the model to estimate amount of runoff and sediment yield in each year. The analysis showed no significant difference between observed and estimated values at 5% level in both all erosion plots and the average of measured values of all three different aspects. The results indicate that the model is capable to determine the quantity effects of rangeland conservation practices in hydrological and soil erosion processes. Overall, the present study suggested good potential for application of the model in the same rangelands of dry regions.

Desertification is specific phenomenon of arid, semi-arid, dry sub humid regions. This phenomenon has a high rate in developing countries such as Iran. The main objective of this research was calibration of IMDPA model in Abuzeidabad (Kashan) region with emphasis on land criteria. IMDPA model, introduced by Iranian researchers to assess desertification intensity in Iran. Before application, the criteria and indices applied in model were re-defined For this study. Regarding to region conditions three criteria were defined as key criteria for desertification which were: Geology-geomorphology, soil and wind erosion criteria. Then each criterion was assessed based on selected criteria, which resulted in qualitative mapping of each criterion based on selected criteria. Finally, by mean of all the indices and criteria desertification mapping was provided and these results obtained. Regarding the studied criteria, Geology– Geomorphology benchmark has the highest effect on desertification. Among the total studying are (16161 hectars), the medium class is about (4792 hectars), and the high class is about (11369 hectars). Among indicators, slop index with 3.9 and lithology sensitivity to erosion and wind erosion with the value of 3.5 and 3.4 are the main indexes of increase in desertification intensity in the study area. According to map of desertification statue 70.3% of study area have a high intensity and 29.7% have a medium intensity.