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SUMMARYThe study area of Mashhad-Chenaran, measuring 223989.7 acres, is the largest and most important subbasin of Kashafrood. This area consists mostly of mountains and plains with variable slopes. The study area is an uneven land type and thus prone to soil erosion. Various practical methods have been developed to study soil erosion both qualitatively and quantitatively, but most of them do not accurately process information regarding soil erosion. Therefore, it is essential to confirm the credibility of these methods by investigating the results yielded by examinations compared with measured quantities taken from watersheds of Iran. The importance of the practical role of soil maps in evaluating erosion and sedimentation must also be considered. In this study, both MPSIAC and EPM were used to estimate erosion and sediment yield. Sediment measuring stations showed a rate of 2.74 t/ha per year; however, the MPSIAC model showed a rate of 1.56 t/ha per year and the EPM model showed a rate of 5.73 t/ha per year. Both the EPM and MPSIAC models were created in countries with climates and geology attributes that differ from those of Iran. Hence, the coefficients and factors affecting erosion do not correspond precisely to the conditions in Iran.

Land drainage is an operation which increases land production and ensures sustainable land use. Soil scientists attempt to arrive a scientific procedure for assessing the efficiency of drainage system, among the correlation between soil morphological characteristics, mainly soil color and redoximorphic features and water table behavior. The aims of this study were investigating the efficiency of drainage system through soil morphological and micromorphological characteristics and judge about the existence of episaturation or endosaturation, in Khuzestan sugarcane cultivated lands after years of artificial drainage. 5 pedons were dug and characterized based on their morphological and micromorphological features. The characteristics of redoximorphic features showed no considerable differences in drainage class between artificial drained field and virgin land. The only contrast was shallower ground water table in virgin lands. 4 pedons were classified as somewhat poorly drained and one as well drained. These drainage classes show that despite the existence of artificial drainage system, the problems haven't been eliminated yet. All pedons showed horizons with low chroma colours in deeper horizons and different types of redoximorphic feature. Micromorphological observations proved that the lands were involved in Endosaturation due to high ground water level.

The intensity of soil erosion to occur in a region depends on multiple factors including climatic conditions, elevation, terrain, soil type, and land use. Among these factors, land use is one of the particular importance as it reflects the outsized role of humans in the exacerbation of erosion condition. This study aimed to investigate the effects of land use changes on soil erosion in Qaresu watershed, using Remote Sensing (RS) and Geographical Information System (GIS) techniques, a watershed with an area of ​​4370.8 km2 located in the center of Ardabil province, northwest of Iran. For this purpose, the 1985 and 2015 Landsat images captured by TM and OLI-TIRS sensors were used to develop the land use maps of the watershed area using the maximum likelihood method. The erosion zoning maps were then developed by integrating the maps of land use, slope, lithology, distance from roads, distance from streams, precipitation, and soil using the Weighted Linear Combination (WLC) method after an AHP-based weighting stage. The results showed that in the 30-year period from 1985 to 2015, the region has experienced a decrease in the area of forest, dry farming, and rangeland land uses and an increase in the area of land uses defined as urban, barren, irrigated farming, and water cover. In total, dry farming and rangeland were the largest land-uses in the studied area. According to the developed erosion zoning maps, in 1985, 14.4% and 36.84%, and in 2015, 15.64% and 32.3% of the studied area belonged to high and very high risk zones in terms of erosion potential, respectively. In defined two periods, high risk and very high risk zones were mostly positioned over dry and irrigated farmlands.