نشریه پژوهش های آبخیزداری
پیاپی 105 (زمستان 1393)

In this study, which lasted for 7 years due to two factors on annual precipitation and growing season precipitation ranges were Tang Laybid Yazd. The study area was the type of dominant vegetation types Artemisia aucheri. This type of plant was selected in three key. In every key area of 100 meters within 10 meters of each other transectbased and transect was placed on the slope 10 plots along each transect was calculated as 1 × 1 m square with a clear and proven choice and Available forage in each plot was measured by weighing and clipping method.. The results showed that the total amount of forage production with an annual rainfall level is 95 percent and The total yield of forage growing season with rainfall positive correlation. Rainfall during the growing season than other years was the appropriate rate will be higher yield

Rangelands are composed from different plant species and different habitual conditions. Growth and phenological characteristics are different in plant species. So rangeland species in each of the months of the season have the certain nutritional value. Thus preference value of forage plants for livestock is an important factor which this desirability in determination of range condition, range capacity and scientific management of rangelands can be used. Thus attention to the preference value of plant species in a region is a key factor which can guarantee the success of management in achieving its goals. In addition, recognizing the preference value of plant species for maintaining native species and supplying palatable forage for livestock is useful. Therefore the preference value of plant species by timing method for sheep was determined. Method was this form That within 4 years and 6 months (May, June, July, August and September) and two times in one day each month and each time about 20 minutes from of grazing sheep was shot The results showed in %1 level There is significant differences Between different species in terms of duration and Percent of the time grazed. ANOVA results showed that Percent of time grazing in different species has significant differences in1% level. Also ANOVA results showed that Percent of time grazing in different species had significant differences between species in different years, but time grazing and percent of time grazed In different months at 0. 01 level was significant. Result Showed that in addition to environmental factors such as grazing season, other factors such as quantity and quality of forage available for grazing by livestock are involved in the selection of plant species

Fresh water is becoming a scarce resource of the arid region. The only option left to manage with this situation is to conserve water resources. Since the amount of rainfall and evapotranspiration rate vary within a watershed, available water for surface and groundwater recharge also varies both on spatial and temporal scales. Moreover, groundwater recharge (and ultimately the total water yield) is directly influenced by the soil texture and land cover in the watershed.
In this study, the distributed Thornthwaite-Mather water balance model for the Yazd-Ardakan catchment in Iran was developed based on monthly precipitation, potential evapotranspiration maps and water holding capacity map. The amount of annual runoff from the catchment predicted by the model is 66.7 mm, which is accumulated in the plain and then salt desert. Half of discharge is contributed by the direct runoff and the groundwater contribution is significant.
A statistical comparison of the estimated and the measured stream flow of Pishkouh show the mean monthly and mean annual estimated and measured stream flows, the correlation coefficient between measured and estimated stream flows, the mean monthly and annual percentage error of estimation and the 90% confidence interval for the mean stream flow. Since the study of water balance using the TM method with the help of remote sensing and GIS was found to be very helpful in determining the amount of monthly runoff in an arid region like the Yazd-Ardakan catchment.

Nitrogen is one of the most important factors affecting the efficiency and soil fertility and the development of cultivated plants, as the most yield-limiting nutrient element in crop production in most soils worldwide. In this study the effects of lignin addition on nitrification in loamy clay sandy soil was investigated in the greenhouse. Therefore soil treated with different rate of lignin ( 0, 50 and 200 mg per kg soil). Lignin used in this study was obtained from black liquor the Kraft process. The results of this study showed that addition of lignin to soil pronouncedly affects the amount of NH4 , NO3-and total soil nitrogen (p

Effect of different watering durations on soil seed bank diversity and frequency was investigated. The study was conducted in Vaz rangelands of Mazandaran province. Soil samples were collected øin 40 1 m 2 plots from two different depths (0-5 and 5-10 cm) through randomized-systematic method in December 2010. Watering treatments were carried out in equal volume of water in different time interval including: one day, two days, four days and a week. The data were statistically analyzed by the SPSS software program. The differences between the means was compared using Duncan test (P

The description and quantification of soil structure is very important because of the many agronomic and environmental processes related to the arrangement of secondary soil units (aggregates) and their stability. The purpose of this study is to evaluate indices used to characterize soil structural stability based on Khozestan sugarcane Agro-Industries data. According to this, 155 soil samples from 0-40 cm were collected to establish regression equations predicting mean weight diameter (MWD), De Leenheer and Deboodt (DDI), Middleton’s dispersion ratio (DR) and water dispersed clay (WDC) indices and to introduce most important factors influence these indices. Further, the possibility of using the geometric mean (dg) and geometric standard deviation (σg) of soil particle diameters instead of soil particle size distribution to derive regression equations was investigated. These results indicate that sodium adsorption ratio and organic carbon were the most important factors that influence the MWDand DDI indices,respectively, with a grade of 81.8 and 27.8 for MWD and 61.3 and 15.2 for DDI. Also, among the features that influence the DR, greatest role was related to sodium adsorption ratio, whereas, clay content, organic carbon and calcium carbonateprovided later ranking of evaluation. Electerical conductivity, calcium carbonate, sodium adsorption ratio, organic carbon and sand content, almost, have the same portion in predicted WDC. Maximum correlation(R=0.97) found between MWD and DDI. Also, results showed that the descriptors of the particle size distribution (dg and σg) did not improve the accuracy of indices prediction.

Natural resource management is among the important challenges encountered in most developing countries that requires explicit consideration of stakeholders’ interests as well as new techniques application. To do this, it is necessary to allow stakeholders to participate in decision making process and express their views across all stages of the process. Decision Support Systems (DSSs) as computer-based tools, assist stakeholders to reach their final informative decisions. To warrant the success of DSSs, it is crucial to bring together and assess the ideas, comments, and feedbacks of stakeholders during, and after the development process of a DSS. In this study, following the development of a DSS for the participatory integrated management of the Chel-chai Watershed in Golestan province, through conducting a filed survey and completing a questionnaire, the ideas and feedbacks received from the potential users of the Bayesian DSS were collected and assessed. The different groups of attendants in the survey were compared based on their responses using two statistical tests (the Mann-Whitney test and the Wilcoxon test) conducted in the R package.The results suggest the differences between groups of watershed managers and staff of the local and state offices for natural resource management to groups representatives of watershed communities in each of the questions is not significant at the 0.05 level. The results suggest that through a training course on principles, capacities, and functionalities of DSSs, for the group of managers and staff, the use of DSSs can assist this group of stakeholders in decision making process. As a result, application of DSSs can become a routine procedure for this group of stakeholders. In contrast, given the poor status of literacy and the computer skills of the watershed communities in the study area, the direct use of this type of computer-based systems is not expected and effective. Communication with some intellectuals among the watershed communities to provide some information and skills, can be an effective solution to the above shortcoming.

Decision-making in the Integrated Watershed Management is quite complex due to existence of various factors and indices there. To access a specific purpose, there are several solutions, each with a different priority to the different issues such as physical, ecological, socioeconomic, and political and security sectors. This requirement leads naturally to multi-criteria decision-making method, which aims to choose the best answer from among the possible solutions. The solution of decision-making problems so complex that the finding an acceptable solution is not easily possible. In particular, they often conflict with each other, so the increase of the value of one factor in priority could reduce the desirability of another one. Therefore, a special case study (the prioritizing of managerial scenarios for Chel-chai Watershed, Golestan Province) is performed to survey the differences in rate of response, due to changes in the types of compensatory multi-criteria decision-making techniques. In this study, four standards of physical, social, economic, and ecological indices, with two different weighting methods (quantitative and qualitative) are used. In order to prioritize management scenarios, some proposed techniques of TOPSIS, SAW, linear assignment, and VIKOR are utilized. Finally, in order to combine rankings, the techniques of Borda and Copeland are applied. According to the obtained results from all the methods proposed to prioritize scenarios, Scenario A (maintain status quo) is validated as the last priority in the list. However, the scenarios with having the garden is the first priority, and the scenarios with agroforestry and forestry activities are listed as end ones. According to the results, here gardening is an important activity, which needs special attention, and other activities are next priorities. Furthermore, we can say that the weights assigned to the criteria in prioritizing scenarios have a significant impact. There should be given careful consideration in calculating the importance weights. The results of the combined ranking of the proposed techniques using two different weighting methods are more compatible with the VIKOR method. Therefore, this method can serve as an appropriate technique to prioritize scenarios.

Select appropriate Alternatives considering all effective desertification measures can have effective aid in controlling, Reclamation and rehabilitation of degraded areas and prevent the destruction of endangered areas. Therefore, this study was performed to provide a systematic and optimal Alternative in a group decision-making model. To this end, first in the framework of Multiple Attribute Decision-making (MADM) the preference indices were obtained using Delphi model, and then priority Alternatives were evaluated using Linear Assignment method (LA). Based on the results, to prevention of unsuitable land use changes (A18), the vegetation cover development and reclamation (A23) and modification of ground water harvesting (A31), were identified as the main combat desertification Alternatives in the area, respectively. Therefore, it was suggested that the results and ranking obtained should be considered in controlling and reducing the effects of desertification and rehabilitating degraded lands plans.

Today, land use change is one of the major problems of the world that has several implications due to population growth. The purpose of this study was to explore the effect of landuse changes on groundwater quality in Zaribar lake watershed. At the first, the statistics with similar climate were selected to reduce the effects of climate on groundwater quality. Then, the map of landuse changes over 10 years (2000 to 2009) was provided using Landsat satellite images and ENVI4.5. Finally, spatial changes of ground water parameters including EC, SAR and TDH were Interpolation using ArcGIS9.3 software. The results showed that the more occurred changes are the forest to agricultural land. Because of the focus of rural residential land in north parts of the study area landuse changes are more in north part of the study area that caused reduced water quality. Also, despite the lack of change in the southern area, SAR parameter has been reduced due to the wastewater collection project.