فصلنامه تحقیقات مرتع و بیابان ایران
سال هفدهم شماره 1 (پیاپی 38، بهار 1389)

Range condition is known as an important indicator for assessment in range management. Many techniques have been exploited for determining this indicator, from which four-factor method has been used in this study. Some communities at stepic regions of Isfahan province were selected. In each selected community, an area was chosen as key area, and a total of eight sites were selected in the key areas. Soil erosion, canopy cover, plant composition, and plant vigor were monitored for each site. The results revealed a significant difference between the sites in terms of the above mentioned parameters, as well as their rainfall (p<0.01). Moreover, there was a significant correlation between annual precipitation and range condition score. The correlation showed different patterns within years in each site, where the difference between years was significant in terms of plant vigor and canopy cover, but non-significant in terms of soil erosion and plant composition. There was also a positive correlation between the trend of individual parameters and the overall condition score. Cluster analysis grouped Aluyjeh, Northern Shahreza, and Charmshahr sites in one branch, Mooteh, Shoorabad, and Golpayegan in another, and finally Komeshcheh and Southern Shahreza in a third branch. The lowest rank for canopy cover, canopy production and soil erosion belonged to Komeshcheh and Southern Shahreza sites. Aluyjeh, Northern Shahreza, and Charmshahr sites were in better condition than the previous group, yet in poor conditions, and the rest of the sites showed the best conditions among study sites. Generally speaking, Isfahan's stepic rangelands are ranked as poor to very poor, while their condition showed a constant trend.

Soil salinity is one of the most important problems of arid and semi-arid regions in the world. Based on Food and Agriculture Organization report, more than 40% of Iran’s under Irrigation lands, are against secondary salinity. Nowadays biological methods are widely used to confront, soil salinity problems. However, significant achievement will take place when plant reserve resources having desired genetically changes, be available. Various resistances against salinity are due to plant genetically variations and selection for just one factor will not be a suitable criteria in measurement of this experimental property. To choose resistant varieties, it is necessary to notice to a set of indexes to create changes in physiology, anatomy, and morphology of plant species. The study of salinity stress on three range plant species of Chenopodiaceae family was the main objective of this experiment. The study conducted in completely random design with factorial experiment and four replications. Experimental treatments were three Salsola species and seven levels of salty water solution containing pure sodium chloride with concentration of 0, 100, 200, 300, 400, 500 and 600 mM. Results of the experiment showed that salinity affected the plants morphological and anatomical characteristics. With increasing salinity rates, some morphological changes such as; leaves falling, chlorosis and succulence were observed. Anatomical changes such as accumulation of crystal salt in mesophyll cells and increasing of trichomes for evapotranspiration decrease and salt exclusion were also observed in the species under study.

With respect to importance of desertification issue and complication of this phenomenon because of interaction of different and numerous variables during the time, paying effective attention to the optimum alternatives is vital for prevention of de-desertification or rehabilitation and improvement of degradation lands so the loss of limited capitals are prevented and efficiency of control and rehabilitation projects is enhanced. Study of research sources showed that unfortunately proposed alternatives are superficial and there are not any precedence in application of systematic methods such as Multiple Attribute Decision Making (MADM) for desertification issues. Therefore in this research AHP method has been used for offering the optimal alternatives for de-desertification. In this study the opinion of experts about alternatives and criteria were assessed by using Delphi method and Pirewise comparison and with application of EC software. Then final preference for the alternatives was obtained with synthesis and integration of the results. The ability of the model was assessed for offering de-desertification alternatives in Khezrabad region in Yazd province. On the basis of obtained results unsuitable land use alternative with weighted average of %22.9, vegetation cover development and reclamation with weighted average of %21.8 and modification of groundwater harvesting with weighted average of %19.1 were determined as the optimum de-desertification alternatives in the study area.

Puccinellia distans is a perennial range species from Poaceae family. The current research was performed to evaluate different priming treatments effect on improving seed germination in P.distans. For this purpose a factorial experiment with a completely randomized design in four replications with 3 priming treatments (9 levels) was conducted. Treatments included salicylic acid (100, 200 and 300 mg/l), gibberlic acid (125, 250 and 500 ppm) and ascorbic acid (100 and 300 mg/l). The time of each of mentioned treatments was considered 10, 24 and 8 hours, respectively. Distilled water was used as control treatment. Evaluated germination characteristics were percentage and rate of germination. Results indicated that priming application has had considerable influences on seed germination so that there are significant differences between obtained results. Priming with salicylic acid (at 300 mg/l level) had the highest effect on germination.It increased germination percentage up to 40% and germination rate up to 1.8 seed/day compared to control treatment.

Ground Water quality change is due to mismanagement in use of groundwater resources. Main objective of this research was to investigate spatial variability of chemical properties of ground water. In this research chemical properties such as cation, anion, sulphate and carbonate were studied. Normality of data investigated based on Kolmogeraph- Smirnov test. Then, variogeraphy analysis was done in geostatistical methods. Accuracy assessment was investigated based on mean absolute error (MAE), residual mean square error (RMSE) and correlation coefficient (R). Results showed that geostatistical methods have more accuracy than determinestic methods. However, global polynomial interpolation was the best method for mapping cation. In addition, for the most parameters, Cokriging method was the best method for interpolation.

Presently, unplanned changes of land use have become a major problem. Most land use changes occur without a clear and logical planning with little attention to their environment impacts.Since that landuse change occurring over large areas, remote sensing technology is an essential and useful tool for landuse change detection. In this study,after applying geometric and radiometric correction on landsat images of TM(1988) and ETM+(2001), five techniques of change detection have been used in 80470 hectare in the region of Daresher,Ilam province. These change detection techniques included Image regression, NDVI differencing, Principal component analysis (PCA(, Tasselled cap (KT) and post-classification comparison. In all these techniques, following standarizing maps,change direction has been determined.The accuracy of the results obtained by each technique was evaluated by comparison with post-classification method through Kappa coefficient calculation. According to the results, NDVI differencing and PC2 differencing showed the largest accuracy with Kappa coefficients of 0.667 and 0.655, respectively.However, Different change detection algorithms have their own merits and no single approach is optimal and applicable to all cases. In practice, several change detection techniques should be used to implement change detection, whose results are then compared to identify the best approach through visual or quantitative assessment.

On the basis of definition of United Nation Convention on Combating Desertification: “desertification is land degradation on arid, semi-arid and sub- humid arid regions by reason of climate change and human activities”. Also on the basis of this Convention, arid, semi-arid and sub-humid arid regions is regions that quotient between precipitation with potential evapotranspiration is approximately 0.05 to 0.65. Annual temperature averages and total annual precipitation from 45 synoptic meteorological stations for a 30 years period (1976-2005) has been collected the Meteorological Organization of Iran. In this paper for study of spatial spreading trend of arid and semi-arid climates of Iran of bioclimatic index of UNEP (United Nation Environment Programme) were used. Thirty years period divided to three subgroups: (1976-1985), (1986-1995) and (1996-2005). Then for each subgroup provided zoning maps and finally zoning maps were subtracted from each other. Results showed that: (1) The most spatial spread of arid and semi-arid climates observed in third decade and (2) The most severe changes of spatial climate observed in west and north-west and south-east of Iran, respectively.

Flood spreading will be more important and critical if drought occurred in arid and semi arid regions. Object is determination and prioritizing of flood spreading suitable sites for qanats, wells, and springs recharging in arid regions by using spatial multi criteria methods and GIS to combat with aridity and drought critic. Miankouh watershed in south of Yazd with 618 Km2 was selected as study area. In this study spatial economical factors such as proximity to road, qanat, well and spring were considered. Spatial natural factors and constraints such as vegetation cover density, geomorphology, land use and slope were interposed in the tree model. In spatial multi criteria evaluation method, factors were standardized through Boolean and fuzzy logics. Factor weights determined with ranking method. In next step with tree model and visual programming layers were combined in GIS environment that its result was composite index map (CIM) with fuzzy values. As a result, suitable region for flood spreading with values near to one were consisted areas with 15.02 km2 and all three priorities 2.43% of whole area in the watershed. This district had suitable common cover with region implemented flood spreading project. So, this method is recommended for determining suitable flood spreading sites in the same watershed areas.

The effect of pre-cool temperature was studied on seed characteristics including: percent and speed of germination, seedling height, root/shoot length ratio, seedling weight, seedling dry/fresh weight ratio and vigour index in five ecotypes of Dactylis glomerata in laboratory and greenhouse condition. Beside of seed germination characteristics, some vegetative growth properties such as tiller number and leaf area were measured in greenhouse experiment. In laboratory condition, pre-cool germination temperature (4 °C) was applied by two weeks on seeds of ecotypes before standard germination test. In greenhouse, the seeds of five ecotypes were sown on pots with fluctuation temperatures 20±5°C during day and (5-12 °C) during night time. The 4 °C was used as base temperature for cold treatment on 15 and 35 days of seedling growth stage compared control. Data were collected and analyzed using factorial experiment method. Results showed, some ecotype like Gene bank had higher values for percent and speed of germination and vigour index than other ecotypes in both experimental conditions. The same ecotype had higher values for tiller number and leaf area than others in both control and cold treatment. It follows by two ecotypes of Hamadan and Karaj with high level of tiller number and leaf area in reaction by cold treatment compare with control in greenhouse. With regard to results, for all seed characteristics, tiller number and leaf area, Gene bank and then Karaj and Hamadan ecotypes were superior compared with other ecotypes.

Low quality flood irrigation are used on desert area of KaleShoor river of Sabzevar since 1992. The main objective of this research was to asses changes in soil salinity affected by low quality flood irrigation. To meet this, 51 soil samples were taken and tested in the laboratory for salinity and indicators require. soil samples taken from depth of 0-30cm, 30-60cm and 60-90cm at the beginning, middle and end of the cultivated rows of the land. Three soil samples were also prepared from the control area. The results showed that EC and PH values reduced in all samples, compared with control points. In addition, organic materials and sand particles which carried by flood water, improved the soil structure and texture of the study area. This study also showed that flood irrigation has been able to reduce gypsum from range of root zone and transported to lower layers.

Desert is a location in which life of plant and animal is hardly possible. In desert formation, different parameters including: climate, geology, vegetation, pedology, hydrology and geomorphology are special and their interaction to each other plays an important role. For desert area vegetation and their boundaries, detailed investigation on such parameters and their interaction to each other is necessary. In this research, desert area of Markazi province was studied from the view point of vegetation. With determination of desert area boundary and gathering detailed data on such an area, the combating desertification and proper use and planning of desert area is possible. For this reason, first of all, the dominant vegetation types were determined and digitized using GIS with Ilwis academic program software. Then the dominant vegetation types were divided to different groups. The map of desert area and their boundaries were determined with taking into consideration the existing data and information and vegetation types characteristics. The result shows that the total desert vegetation types are 276074 ha with 21 special desert vegetation types and their potential capacity were determined. The result also show that the widest desert vegetation types are Hultemia persica – Scariola orientalis with 77833. 8 ha which are distributed in Saveh, Arak, Delijan and Khomain townships and smallest desert vegetation type is Nitraria schoberri with 299. 5 ha in marginal salty land of Mayghan playa. Finaly, vegetation map with boundaries of 21 desert vegetation types produced for this study area. ation types.؟

Managing ranch units has been one of the important issues during the last decades in studying the rangeland of Iran. The most noticeable system for range management based on grazing licene is one of the three types of council، collective and private exploitation. One of the implementing methods concerning the balance between livestock and range and reduction of range degradation is the introduction of reasonable range utility units. The present study seeks to compare different ownership types with considering independent variables of rangeland condition، exploitation and the capability degree of collective and private ownership so as to introduce the most appropriate method for user's inclination and better quality. According to goals and assumptions، 105 questionnaires were completed through direct interview with exploiters (only those who owned grazing licene). The state of the rangeland in 41sample ranges was calculated through 4 factories. The results showed the condition of private rangeland has been obtained to be better than the collective rangelands، however، no meaningful difference in rangelands management methods in this type of possession. Because of improper exploitation methods in this county، council exploitation is not suggested. Despite its probable weaknesses, the collective possession، because of its high partnership spirit among collective beneficiaries، by some conservatism can be more appropriate than other types and its deficiencies can be reduced by proper management and create the motivation of conserving natural resources by special programs among people. Regarding that the majority of ranges are commonly used, establishing cooperatives and giving the right of utilization to cooperatives is of priority based on the people's opinions.