علی خنامانی

According to the concept of desertification, which is land degradation in dry areas, the semi-arid, and dry sub-humid due to many factors such as climate change and human activities, this phenomenon has long been known as a serious problem in terms of economic, social, and environmental in many countries. The purpose of this study was to study the desertification of Faryab city in southern Kerman province using Iranian IMDPA method.

The aim of this study was assessed desertification potential of Faryab region in the arid region of south of Kerman province by using the Iranian model of desertification potential assessment (IMDPA) on soil and vegetation cover indicators.Each criterion was assessed based on the selected indices which result in qualitative mapping of each criterion cased on geometric average of the indices. Thematic databases, with a scale of 1:50000 were integrated and elaborated in Arc GIS 9.3. By laminate of thematic databases layers and using this formula DM=(VQI×SQI)1/2 to Calculate the geometric mean Criteria. Then Desertification intensity map was obtained with analysis IMDPA Model.

Results indicated that 14.53% of study area classified as low class, 33.69% is classified as moderate class and 51.78% of area classified as a severe class of desertification. Analysis of desertification criteria in Faryab region showed that among study criteria, regeneration of vegetation of vegetation cover is a major problem with a geometric average of 3.82.

According to the results of this research, which indicates the importance of vegetation in desertification, it is suggested that a deeper investigation of the appropriate methods of remediation and improvement of the rangelands of the region be undertaken by the Natural Resources Department. In the case of lack of attention from the authorities, about 50% of other (medium and low desertification classes) will be subject to severe destruction, which will lead to damage to other elements of the ecosystem, including wildlife, and so on.

The number of stormy days is determined by various factors such as wind speed, rainfall, soil moisture and so on. The study of this index in the country can be considered in various plans. The purpose of this research is mapping of the number of dusty stormy days in Iran and selecting the best model based on the climatic data of 150 meteorological stations for the period of 25 years (1986-2010).

Dust stormy days’ data of the studied stations were analyzed using variogram curves to represents their spatial correlation. Gaussian variogram (R2=0.96) shows the highest correlation between the data. Then, map of the number of dust stormy days in Iran were prepared using different geostatistical and mathematical methods. For this purpose, several mathematical interpolation methods including Inverse Distance Method (IDW), Global Polynomial Interpolation (GPI), Radial Basis Function (RBF), Local Polynomial Interpolation (LPI), and geostatistical method of Kriging were used. To select the best interpolation method among several geostatistical and mathematical methods, statistical indicators of Root Mean Square (RMS) and correlation coefficient between observed and predicted data were used.

Results show that the highest correlation between predicted and observed data (R2 = 0.74) was found in kriging indicator method. The southeast and southwest of the country have the highest number of dust storm days.

High number of dust stormy days in the southeast is resulting from drying of Hammon lakes and blowing of 120-day winds in Sistan plain, and entering of dust from Arabic countries form the direction of southwest. North part of the country has the lowest number of dust storm days.

One of the most important environmental problems in the south of Kerman is the influx of fluids into man-made structures and residential areas, requiring careful consideration and a practical solution. Ammodendron Persicum is a local species of Divdal, firewood, lumber, sand, tree, sand, and thistle and is native to Qaen and Taybad in Khorasan province. Being a sub-family of the butterfly (Papilionaceae), it belongs to the legume family (Fabaceae). Divdal is a shrub-like species with a height of 6.8 m whose critical activity generally begins in the second half of March. Moreover, it flowers in mid-May and sows until late June. It generally grows in a rainfall rate of 70 mm, but the species grows well in 150 mm rainfall, being highly drought-resistant as a result. Horizontal and vertical expansion of the roots of this plant is one of the reasons for its drought resistance. Divdal regeneration in the arena occurs in the form of seed and branch. It has a particular dependence on anthropogenic sand, as it only germinates on these habitats. Overall, due to the Divdal ecological features, the species is suitable for germination on sand dunes, reduces wind speed, and has good prospects for use in other areas.

To identify susceptible areas of Divdal species (Ammodendron persicum) in southern Kerman through the Hierarchical Analysis (AHP) method, all factors affecting Divdal species growth were identified as layers of precipitation, altitude, geomorphology, Salinity, and land use (Fig. 2). Then, all layers were processed and evaluated in the same GIS environment using the same reference system with the same scale and the same cell size. To determine the significance of the indices, the relative importance of each criterion was determined via a hierarchical analysis model, using the Expert Choice software. Each criterion was then fuzzed by ArcGIS software and was numerically zero to one. Next, by integrating the AHP and Fuzzy models, all the standardized layers in each of the weights were obtained from the hierarchical analysis model. They were multiplied and thus transformed into fuzzy weighted layers. In the next step, multiplication and fuzzy multiplication operators were performed on the layers and overlapping layers, and finally, by fuzzy map classification, the final map of Divdal species susceptible areas was prepared.The hierarchical analysis process begins by identifying the elements of decision making and prioritizing them. In the placement process, evaluations are made after defining the overall goal and identifying the criteria that are effective in reaching the right place.

In this study, the results of the AHP model showed that out of the five main criteria in locating Divdal species susceptible areas, land use, precipitation, elevation are ranked among the top three with their relative importance being 0.38, 0.25, and 0.18 respectively. Also, geomorphology and salinity ranked fourth and fifth in this regard, with relative importance reported as 0.11 and 0.08, respectively.

Geomorphologically speaking, the Divdal species prefers mostly plain as its growth site. Moreover, erosional, mountainous, and lowland areas were identified as suitable grasslands for this plant. accordingly, erosion and impoundment with the relative importance of 0.54 and 0.26 are of most importance in the establishment of Divdal species, and covered plain, mountain, and plain with the relative importance of 0.11, 0.05, and 0.02 are respectively at the lowest level of significance. In terms of annual precipitation, it could be argued that Divdal species grows in low-rainfall areas, but the higher the precipitation rate is, the better growth would come about. Analysis of the questionnaires revealed that precipitation greater than 180 mm/year was identified as the most important and precipitation less than 70 mm/year as the least important areas for Divdal growth. In this regard, precipitation of more than 180 and 180-100 mm are ranked first and second with significance levels of 0.56 and 0.26, respectively. On the other hand, precipitation rates that fall in 70-100 and less than 70 class with the relative importance of 0.11 and 0.05 are considered less suitable for Divdal growth. In terms of its resistance to salinity, the salinity of 0 to 4 dS /m was selected as the best growth area for this species, as with an increase in salinity, the importance of this sub-criteria decreased. Thus, the salinity of 0-4 dS/ m has the relative importance of 0.71, and salinity classes of 4-16, 16-32, and more than 32 dS/m have the significance of 0.14, 0.08, and 05, respectively. As for the suitable height for Divdal species growth, altitudes greater than 800 m with the relative importance of 0.66 was selected as a suitable height for growth of this species, considering the fact that Divdal is a cold-resistant species. Also, areas less than 800 meters high with a significant rate of 0.33 are less important in this regard. In terms of land-use, since the Divdal is a completely sandy species (Psammophyte), land use was, therefore, divided into two sections of sand and non-sand dunes, and the use of sand dunes with relative importance. 0.9 is considered as the most important, with other land-uses having relative importance of 0.1. The results of this study indicated that AHP was a very convenient and easily applicable method for locating suitable areas for the cultivation of various plant species and its integration with powerful tools such as GIS enhanced its efficiency. According to the research findings, it could be argued that the use of a hierarchical analysis method in environmental planning is very important and could help planners put a natural problem into a hierarchical structure and then quickly and accurately find a solution for it.

Diversification of used species in sand stabilization and desertification can help sustain these ecosystems. Most species used in sand stabilization require initial support to adapt to new conditions over time. One of the most important of these supports is irrigation in the early years of planting. In this study, the yield and water use efficiency of (Ammodendron persicum) in lysimetric conditions under the influence of different levels of irrigation were considered. Different irrigation levels consisted of 75, 50, and 25 percent irrigation and field capacity (control), applied in a completely randomized design with four replications. Evapotranspiration rates in control, 75, 50, and 25% under-irrigation treatments were 60, 47, 37, and 26 liters, respectively. By calculating water use efficiency based on the amount of dry matter produced per liter of transpiration water, it was found that there was a significant difference between different treatments. The highest water use efficiency with 2.07 g of dry matter for per liter of transpiration was related to 50% irrigation treatment. As the water consumption decreased, the root to aerial part ratio increased, so that it showed a significant difference in different treatments. The root to aerial part ratio in the control was 0.84 and in the 75% under-irrigation treatment was 1.51. The results of this study showed that Ammodendron persicum in the early stages of establishment due to low growth rate had low water requirements and improved its water use efficiency through various mechanisms such as root development. Due to the low growth, water loss through evaporation in early stages of establishment was high, and to improve irrigation efficiency, appropriate methods to reduce evaporation and maintain soil moisture are recommended.

Over the past decades, due to increased population and consequent increase in the need for food, we have seen extensive changes in land use, and in particular, the increase of agricultural lands. The aim of this study was to evaluate the changes in land use in the Bartash plain in Dehloran city of Ilam province during 26 years from 1988 to 2014 using the object-oriented approach. To accomplish this research, the necessary corrections were made after the acquisition of Landsat TM (1988), ETM + (2001) and Landsat 8 (2014) satellite images, and then, using the object-oriented method, the land use map was prepared for the three time periods. The results of the evaluation of the accuracy of the produced maps show that the highest accuracy and Kappa coefficient with the values of 90 and 95% correspond to the image of 2001, and the lowest them with the value of 80 and 90% was related to the image of 1988. Total accuracy and Kappa coefficient in the image of 2014 with 90% and 92%, respectively show a good accuracy. The results of land use change trend showed that the land use of the fair rangeland had the most changes with a decrease of more than 21 thousand hectares. Agricultural lands are in the next place, showing an increase of over 15,000 hectares (twofold) that could be due to the increase in population and the availability of adequate water resources in this area. The land use of poor rangelands also shows an increasing trend of 1.5 fold, indicating the degradation of fair rangelands. The saline lands initially show an increasing trend but then show a decreasing trend due to converting to agricultural lands. The overall accuracy (900-90) and kappa coefficient (95-90) indicate the high accuracy of this method in determining the land use.

Detection and prediction of changes in landscape, is necessary for the maintenance of an ecosystem, especially in developing countries with rapid changes and without planning. The object of this research, is monitoring landscape changes in past and it’s simulation for future using Markov chain Consolidated and automated cells (CA-Markov) in arid and semi-arid region of Meymeh Dehloran, Ilam. Landsat satellite images of (TM) 1985, Landsat (TM) 2000 and Landsat (ETM) 2016 were used. Change detection maps were prepared in seven classes of agriculture, Forest, fair range, poor range, rocky protrusions, residential land and salt land using supervised classification ARTMAP FUZZY neural network. Accuracy of the classification landscape maps for 1985, 2000 and 2016, are 93, 95 and 93 percent, respectively. Changes in landscape were predicted for 2030, using Markov chain model and automated cells. Predicted matrix results based on 2001 and 2016 maps showed that in span of 2016-2030, it is likely that 13% of agricultural land, 54% of Forest, 48% of the fair range, 82% of poor range, 55% of rocky protrusions, 52% of the residential land, 93% of salt lands and marsh land converted to other land uses. To validating the model, simulated landscape map of 2016, were compared with satellite image classification of the same year. Kappa coefficient was 87%, which shows the high capabilities of CA-Markov model to simulate landscape changes in arid and semi-arid region of Meymeh Dehloran.

Over exploitation and improper usage of non-renewable resources and long-term drought cause vegetation cover degradation and desertification in many parts of Iran. Artificial recharge of groundwater by controlling and spreading the floods could be an appropriate solution for most areas. Among the different evaluated parameters, the soil texture and specially clay value affectedthe amount of soil cohesion and erosion threshold. The main purpose of this study was to investigate the effect of clay value on erosion threshold in flood spreading projects. In this study, an open flume with 100 m length was used to simulate an overland flow with a 10 cm depth. Five clay value treatments of 0.06, 0.12, 0.18, 0.24 and 0.30 were examined and in each treatment, three experiments were conducted and in each of them the discharge rate and the depth of flow were directly measured and the flow area as well as flow velocity were calculated. In the next step, the erosion and sedimentation depths were individually measured for each experiment. The results showed that the distance of threshold value increased with the increase in clay percent of soil.Moreover, the threshold values were estimated for different clay value treatments of 56, 60, 65, 75 and 95, respectively. The results also showed that the flow velocities increased with flow length.

Underground water resources considered as a major source of fresh water. Increasing need to water in Iran, causing to immensely utilization and ground water balance disorder, so that state of ground water in many of area is negative.The purpose of this study is to investigate the trend of changes in some of the characteristics of groundwater during the period 1374 to 1387 is Segzi plain. For this purpose, data gathered from the Organization of regional water and homogenous test with Tom test (Run-test) at 95% confidence level was performed on the data. The independence of data evaluated by time series auto correlated functions (ACF), to do this, the amount of auto correlated data computed in different time delays and finally Mann- Kendall test used to evaluate the trend of time series properties in groundwater. The results of Run-Test showed that all of used series in this study were homogenous (P value< 0.05). The result of trend analysis test for region’s wells showed a significant increase in chlorine in underground water resources (P value< 0.05). Calcium has an increasing Trend too about 3 units. Results also showed that all used series in this study are random and Mann- Kendall trend analysis test can be an appropriate for trend evaluating in data series. As regard to irregular utilization of underground water resources; by increasing depth of water level, amount of different salts such as chlorine and sodium increased, that causing to surface source degradation like soil and plant cover in agricultural area.

Soil characteristics are the most powerful factors in desertification phenomenon. The purpose of this study was investigating soil characteristics as indices for evaluating desertification intensity. The most important indicators of the soil that affect desertification were selected in the present study. Soil samples were taken from Segzi desert vicinity located in the east of Isfahan city with surface area of 112،167 ha. Soil indices such as Soil texture، soil gypsum percentage، the content of HCO3-1، electrical conductivity (EC)، pH، the percentage of the organic matter، the content of the soil sodium، chloral and sodium absorption ratio (SAR) were selected. All of these indices were calculated on the thirty four soil samples. After ensuring of the normality of the samples by Klomogrov-Smirnov test، the mentioned indices were imported into GIS for delineating soil characteristics maps. To delineate distribution maps of each soil indice، inverse distance weighting and ordinary and discrete Kriging methods were applied، and appropriate method was selected. Each layer was scored based on MEDALUS model، and the final characteristic maps were then generated using soil geometric mean indices. Results showed that the affected areas of the average، severe and very severe classes of desertification were calculated about 66000، 45650 and 517 ha، respectively. The results also revealed that the indices of the organic matter، soil gypsum percentage، electrical conductivity and SAR were the most influential indicators، which affected desertification in the study area.