Assessment of Agricultural Suitability Using Surface Morphometric Indicators: A Case Study of the Western Soums of Selenge Province, Northern Mongolia

Гадаргын морфометрийн үзүүлэлтэд суурилсан газар тариалангийн тохиромжтой байдлын үнэлгээ: Сэлэнгэ аймгийн баруун сумдын жишээн дээр

Abstract

This study identifies and characterizes territories suitable for agricultural production in the western soums of Selenge Province, Mongolia. The western soums cover 19,900 km², representing 44.8% of the province’s total area. The study area lies within the Selenge River basin, which, compared to other river basins in Mongolia, is distinguished by fertile soils, favorable thermal and moisture conditions, abundant water resources, and relatively flat terrain dominated by floodplains—making it a particularly suitable region for agricultural development.According to 2024 statistics, the western soums contain 67% of the province’s agricultural land and 68% of its arable land, with 15.37% of the agricultural land currently under crop cultivation. To assess land suitability, surface morphometric indicators were derived from the HydroSHEDS (Hydrological Data and Maps Based on Shuttle Elevation Derivatives at Multiple Scales) 90 m resolution digital elevation model. Three key factors—elevation, slope, and aspect—were extracted and classified using a reclassification method. To improve accuracy, pairwise interactions among these factors (elevation–aspect, elevation–slope, and aspect–slope) were evaluated using combinational matrices. This approach provided a more realistic and multidimensional representation of morphological conditions than single-factor analyses. Land suitability was quantified on a five-point scale, ranging from highly suitable to highly unsuitable. The results indicate that areas classified as highly suitable and suitable account for 45.72% of the total, moderately suitable areas comprise 19.83%, while unsuitable and highly unsuitable areas make up 38.16%. Considering the spatially uneven distribution of croplands in Mongolia, regionally differentiated evaluations that account for land surface characteristics are essential to support effective agricultural land-use planning. In the future, this methodology can be applied to assess agricultural lands in other regions of Mongolia, with adjustments made for their specific surface characteristics.