Surveying of Iranian Model of Desertification Potential Assessment

Drylands occupied a large area of lands on Earth and a large percentage of the population are living in these areas. Land degradation or desertification is one of the biggest problems in arid zones. In general, little effort for mapping land degradation at regional to global scales has been made. Recent efforts to assess desertification in Iran led to devise the Iranian Model of Desertification Potential Assessment or IMDPA. In this article we intend to consider the concerns of international models of desertification, re-evaluate the Iranian Model of Desertification Potential Assessment in the East of Esfahan and Studies carried out on this model till now to review and to evaluate indicators of the soil, vegetation and erosion in the IMDPA. Our aim in this paper is to clarify many of the black spots of desertification in Iran, we're going to show where to start and what to expect on a study of desertification. In this study, water, soil and vegetation indicators and their indices in 172 homogeneous work units were assessed using the instruction of IMDPA, and the results were compared with a study done in the 90s. According to land degradation and desertification studies we propose a model as " Iranian Model of Desertification Status Assessment " or IMDSA be created in which the three indicators of land degradation, namely the degradation of soil, vegetation and water can be used on it. According to our study, to indicate soil degradation state, the four indices of Tillage Pan, Infiltration, Aggregate Size Distribution and Score of EC and to evaluate vegetation degradation status, the four indices of Alien Invasive or proliferous weed species, Biomass decline, Bare Spots, and proportion of useful species for use in the Iranian Model of Desertification Status Assessment were appropriate

Soil and water salinization in Ghaleh Ghazi region, Iran

Approximately 34% of soils in Asia are influenced by salts. With about 25 million ha of saline and alkaline lands, about 15% of the country, Iran has the most saline lands in Asia after China, India, and Pakistan due to its geographical position, climate and human activities. This research was done due to determine the effective factors on soil and water salinization. At the first the boundaries of this region were characterized using GIS, then landuses were determined for field survey and also soil sampling in nine landuses were done according to both factors of planting pattern and water resources in each unit. The soil profile was prepared and soil samples were obtained from surface depths of (0 - 50 cm) and some factors such as soil texture EC, SAR, pH, CaCO3, Cl and potassium were measured. For study of water resources some samples were obtained from 30 wells and also from upland runoff, then soil and water sample were analyzed and some parameters such as EC, SAR, Cl- and pH were measured. Finally, according to data base, geological map, topography map, landuse map, soil and water measured data and also field studies, soil and water salinization schedule and region status were investigated. The results showed that important factors influencing water salinization in Ghaleh Ghazi region (Iran) are geological formations located in aquifer recharge and climate condition. Important factors of soil salinization in region are irrigation with saline water, improper irrigation method, unsuitable planting method, climate condition and landform

Comparing Some Properties of Crusted and Uncrusted Soils in Alagol Region of Iran

Abstract: The current research was carried out to study effects of biological soil crusts (lichens and mosses) on some soil attributes. The study was carried out in rangelands of Alagol region, in north of Golestan province, Northern Iran. Survey area is located near Iran-Turkmenistan border. In this research, soil samples were taken from two crusted and adjacent uncrusted areas, at one site along 4 transects. Environmental factors, soil texture and vascular plants vegetation of two areas were similar, but due to livestock repeated trampling and wind and water erosion over the last years, there were not lichens and mosses in non-crusted points. Soil sampling was done along each of two transverse 300m transects. Laboratory analyses were done on soil samples from the upper soil layer (0-5 cm). Soil properties included organic C, K, Na, N, and P. Using t-test, above mentioned properties were compared in crusted and uncrusted soils. Results showed that P, N, and organic C were significantly different at depth 0-5 cm. Key words: Biological soil crust, crusted soil, soil characteristics, arid and semi-arid lands, rangelan