Assessing desertification hazard and risk in Sabzevar region using MICD Model

Desertification has turned into serious hazard for many countries especially developing ones such as Iran. The most suitable methods for desertification assessment intensity considered to be experimental models. Iranian desertification model، namely MICD، was used in this study to assess desertification hazard for Sabzevar region. For this purpose، work units map (geomorphologic faces) was created using slope، geology، vegetation cover، land use، Landsat 5 satellite imagery and Google Earth data. Accordingly، four units، 10 types and 96 faces were identified. Desertification map of the model was synthesized after rating the desertification indices in work units. For assessing desertification risk، firstly، the elements at risk were identified and classified. The risk map was developed with a combination of desertification hazard intensity and number of elements and degree of vulnerability maps using the total risk equation. Results showed that «continuity of wind blow (≥ 6 m/s as threshold wind velocity)» and «density of vegetation cover» in rangelands; «continuity of wind blow (≥ 6 m/s)» and «soil accumulation» in bare lands، and «Crop residue management» and «wind break situation around the field» in the farmlands are the most effective factors. Desertification map was created in four classes of low (II)، moderate (III)، high (IV) and very high (V). The vast area of the region is allocated to the moderate class (46. 45%). The highest and lowest elements fall into intensive (V) and very low classes (I)، respectively. Risk map of desertification was obtained in five classes which the largest part (46. 77 %) and the smallest part (9. 16%) of the region was associated with the high and very low classes respectively.