This study was conducted in order to survey factors affecting distribution of vegetation types and the relationship between vegetation and soil characteristics in Sirjan playa, Southwestern Kerman province. The study area was one of the most ancient catchments in central Iranian plateau including formations from Precambrian to Holocene, an area of about 274194 ha. After identifying playa area by aerial photographs and topography maps, vegetation was studied using plotting method along transect. In addition, for pedological study, profiles were dug in each vegetation type. Soil characteristics such as texture, acidity, electrical conductivity, organic matter, lime, gypsum, sodium, potassium, calcium, sulfate and bicarbonate were measured. Results showed that from center of playa toward heights, in all aspects of playa, water table depth increased and electrical conductivity decreased. The amount of anions and cations of soil varied, and ratio of anion/cation was obtained. In addition, soil texture became lighter and stability of soil structure improved. This variation caused different vegetation types from margins of playa to heights of 1650-1710m. Vegetation types established from center to outer of playa were as follows: Halocnemum, strobilaceum-Halostachys, belangriana, Tamarix passerinoides, Seidlitzia rosmarinus-Salsola sp., Seidlitzia rosmarinusArtemisia sieberi. After humid margins, vegetation types such as Artemisia sieberi-Zygophyllum eurypterum and Artemisia sp.-Astragalus sp. were established respectively. Therefore, in this region, two factors such as salinity and water ground table were the most important factors affecting on establishment of vegetation types.

Introduction: Study about quality and characteristics of wind erosion forms and also relationship between these forms with other environmental landforms is an important criterion in the assessment of natural resources. When wind blows on sandy beds, sand grains hop and roll into downwind shaping sand ripples. Morphometry is quantitative analysis of geomorphic characteristics of a region of landforms (Bayati Khatibi, 2010, 2). Study of surface sand grain size shows that larger ripples wavelength are created in the sands and coarse wavelength ripples in finer grain sands (Chorley et al 1985: 434). Ripples are common forms of roughness in desert areas.

Playa is an important landforms in desert environments and covers an extensive area in this type of ecosystem. Playa landform is composed of different geomorphic surfaces. After orogenic activities and evaporation of water bodies remained from Thetis Sea, playa was formed and various evaporite minerals were precipitated. Minerals with lower solubility precipitated in upper parts were the origin of minerals for lower positions. Kheirabad saline-gypsiferous playa in Kerman Province was selected to study physicochemical, clay mineralogy, and micromorphological properties. Clay flat, puffy ground clay flat, wet zone and salt crust are among geomorphic surfaces identified by field studies and Google Earth images in Kheirabad playa. Electrical conductivity at non-saline clay flats varied between 2.8 to 32.2 dS/m. Smectite, illite, palygorskite and kaolinite were detected in this geomorphic surface. Euhedral gypsum crystals and calcite coatings were observed in gypsic and calcic horizons of this position, respectively. Electrical conductivity in saline clay flats varied between 33.5 to 160 dS/m. Lenticular and interlocked plates of gypsum were among secondary gypsum crystals identified in this geomorphic surface using micromorphology. Maximum EC (314 dS/m) was investigated in puffy ground clay flat which is attributed to capillary movement of saline groundwater. Illite, palygorskite, smectite, and kaolinite clay minerals together with calciticcrystalitic b fabric were found in wet zone geomorphic surface. Electrical conductivity and percentage and size of gypsum crystals increased from upslope positions toward the center of the playa, but no such a trend was found for clay minerals.

Assessment of effective processes in the evolution of Aeolian landforms is ine of the main subjects that studied by many researchers in Iran and the world. Iran is Iocated in arid and semiarid region of the earth. For this reason the Aeolian Iandforms can be seen in many parts of Iran. In the basin of Sirjan Playa, Aeolian landforms are spread out in the surfaces of the plain Distributions of these landforms are limited by sand size, soil moisture, speed and direction of wind, sheet flood and vegetation.In spite of this situation, the Aeolian landforms in Sirjan basin are far from typical forms. Assessment of aerial photograph with fieldwork and sampling of the sediments for granulometry have been shown that the evolution of Aeolian landforms is mostly developed in area with of sheet flood activities. In other areas, we can see different forms of these processes.In some parts of the study area, the role of wind erosion can not be seen and the wind erosion does not exist. Finally, the map of zoning of sustainable areas for wind erosion, are prepared.

Segmented fans are one of the arid morpho-climatic system landforms that have drawn a significant attention among many researchers. Various results have been reported by workers studying landforms across the globe. Segmented fans are identified by different specifications such as topographic position, drainage pattern, incision depth, nature of soil profile and desert varnish to other alluvial fans. The goal of this study was to assess effective factors controlling the evolution of segmented fans. In this study, aerial photographs and topographic and geological maps in various scales were used. In addition, mountain front sinuosity, valley floor width to valley height ratio and NUVEL 1 a model were used to assess tectonic activity. The results showed that the evolution of segmented fans in Sirjan playa depended upon tectonic activity as well as climatic changes in which the role of the former seems to be much more important than the latter. In fact, continued down-lift and up-lift of Urumyeh-Dokhtar mountainous region has created the segmented fans in Sirjan playa. Despite this situation, climatic changes during arid and humid periods had a second role in the evolution of alluvial fans. Surface is considered, much more important factor than change of location of sediment assimilation thus creating new fans.

Nebkas are generally appearing in regions that amount of sand is average and sufficient moisture was existed for life of vegetation. Overall, Nebka is self organization reaction of ecosystem against windy erosion stress. In the other word, environmental system is trying to adjust the pressure of windy erosion by the creation of this feature. A wide variety of Nebka landscape is observed in green border of the Sirjan Playa. The aim of this study is comparative grouping of Nebkas in the eastern north of Sirjan Playa, and introduction of the most appropriate type for quicksand stabilization, using analysis of Nebka morphometric parameters, via TOPSIS algorithm. This algorithm is one of the methods of multiple criteria decision making, that it combines the quantitative and qualitative indicators and weights according to importance of each criterion, can help decision makers to choose the best alternative. For this achievement, first, the most important morphometric parameters of 392 Nebkas from Tamarix Macatensis, Seidlitzia Florida, Alhagi Mannifera and Reaumuria Turcestanica type were measured by linear sampling in field. Then, the studied Nebkas were prioritized using comparative evaluation by TOPSIS algorithm. The results show that Tamarix Macatensis Nebka, with weight of 0.818, has the highest of effect in stabilization of quicksand. Seidlitzia Florida Nebka, with weight of 0.151, has less important than Tamarix Macatensis Nebka and higher priority than Alhagi Mannifera and Reaumuria Turcestanica Nebkas. In front, Reaumuria Turcestanica and Alhagi Mannifera Nebkas, with weights of 0.028 and 0.002, have the lowest of efficiency respectively. Therefore, for implementation of stabilization projects of mobile sands in study area, firstly, development of Tamarix Macatensis Nebka system and in the second stage, development of Seidlitzia Florida Nebka system have the highest of importance and efficiency. The results of this study will be beneficial in systemic management of desert regions and stabilization projects of quicksand.

Satellite images and remote sensing approaches are important tools for evaluating, mapping, and managing saline lands in different world regions. The main aim of the present study was to investigate the degree of concordance between maps obtained by machine learning methods and kriging estimator about salinity monitoring of a part of the soils of marginal lands of Sirjan Playa in two seasons, i.e., winter and summer, using two remote sensing data sources, i.e., Landsat 8 and Sentinel 2. Ninety surface soil samples (zero to 30 cm) were collected as a regular grid sampling pattern with 750 meters intervals. Some of their most important physical and chemical characteristics were determined using standard measurement methods. After performing radiometric and atmospheric corrections on mentioned satellite images, in addition to the main bands, 13 salinity indices were used to estimate soil salinity using artificial neural network, decision tree, random forest, and support vector machine models. Besides, kriging maps of soil salinity were drawn for both mentioned times. Results showed a higher performance (R2 =0.87 versus= 0.72) of Sentinel-2 than Landsat-8 in predicting soil salinity.  Moreover, results confirmed that the ANN model developed by Sentinel-2A image had the highest performance (R2 =0.77, RMSE% =27.1) to predict ECe in the winter season. Furthermore, RF presents the lowest error (R2 =0.87, RMSE% =17.4) for prediction ECe during the summer season. Among the studied salinity indices, VSSI index was also selected as the most effective index to estimate soil salinity of region. The results also showed that ECe maps obtained by two methods had a high level of concordance and an overal accuracy of over 80%; however, the change of season and type of satellite affectedthe compatibility of the maps.

This research investigates the contamination of trace elements, nitrate, nitrite, ammonium and corrosive potential in the groundwater of south and southwest of Sirjan city, Kerman province, Iran. Therefore, 115 groundwater samples were collected for Hydrochemical analysis from Sirjan city area, Kheirabad salt playa area, Chahderaz plain, Golegohar mining area, Ghatarbaneh-Eynolbaghar plains and Marg salt playa in July 2016. In descending order, the mean values of minor ions and trace elements are such as: NO3 > B > NH4 > As > Mn > Ba > Cr > NO2 > Cu > Pb > Cd. Generally, the concentration of elements and ions in the groundwater of Chahderaz plain and Marg salt playa is above the maximum admissible concentration (MAC) values for drinking water according to WHO. Also, Cd, B and As have concentration more than MAC in total groundwater samples. Chromium in all of the groundwater samples except in Sirjan city samples have concentrations more than maximum admissible concentration. Moreover, Pb in groundwater of Kheirabad salt playa and Chahderaz plain shows a groundwater contamination. While concentrations of Cu, Ba, NO2, and Sb in all of the area are less than MAC. The evaluation indices showed spots in a high-risk level observed in Golegohar mining area, Chahdereaz plain, KH1, and KH2 from Kheirabad playa and KM1 and KM7 from Marg playa area. Finally, according to Langelier Saturation Index (LSI), most of the groundwater samples are corrosive in this area. Therefore, in the processing plant, corrosive process control of groundwater should be accompanied.

In the desert of Abarkoh Basin, Central Iran, the influence of playa-lake level fluctuations on recent sedimentation mode of a terminal ephemeral fluvial-fan system and adjacent lacustrine/aeolian sediments of a playa fringe environment has been investigated. The surface geomorphology-sedimentology and its relationship with shallow subsurface sediments along a >25 km transect, has been studied. The Abarkoh Basin is a NW-SE trending depression (>150 km long and ~100 km wide) with a megafan (>940 km2) originated to the west and laterally grades into distal fan and playa fringe (desert) environments. The late Quaternary evolution of the area represents the relative dominance of water versus wind transport and deposition as a function of variations in the discharge of ephemeral fluvial systems and fluctuations in groundwater table/playa-lake level. The combination of climatic change, human impact and to a lesser extent syndepositional tectonics resulted in a drawdown of the groundwater table or/and playa-lake level and associated recent periods of extensive deflation/deposition and its related shifts in dune development. Significant erosion and reworking of the dune fields was associated with their position in depocenters, partly controlled by the termination of the fluvial system in the playa periphery and/or the position of playa-lake level. The latter resulted in development of a sandy saline pan. This study emphasizes the importance of the rapid sedimentary and geomorphic environmental modification in distal parts of the terminal fans-playa fringe environments, areas that are particularly sensitive to desertification.

There are more than 60 large and small playa In Iran. One of them, is Khoor playa. The aim of this study is investigate the reason of choice for extraction minerals from Khoor playa in Iran. With extensive studies and various reports, Khoor playa features was locating the best place with having the best conditions, for the construction of KCl from playa. In Khoor Playa has been exploration in two stages: exploration, identification, networking, roads construction, sampling and next stage is exploration on the salt crust was made with an area of 1000 square kilometers. Exploratory studies were conducted in Khoor playa in 2, 000 square kilometers. Brine extraction for usable area is 1000 square kilometers and salt crust average thickness is 6 meters. Taking into account the porosity of 10%, 600 million cubic meters of brine was estimated available in the playa, if the coefficient of 75% to determine the extractable brine consider, this amount is 450 million cubic meters. The reasons for choice this Playa compared to another playa in Iran are high grade KCl, large area and thickness of the shell salt, high brine reserves, close to town and access roads built.