University of Tehran Press Iranian Journal of Soil and Water Research 2008-479X 56 8 2025 10 23 Assessment of the Impact of Land Use Change on Soil Physical, Chemical, and Biological Properties: A Case Study in the Loshan Region, Guilan Province Assessment of the Impact of Land Use Change on Soil Physical, Chemical, and Biological Properties: A Case Study in the Loshan Region, Guilan Province 2179 2197 104846 10.22059/ijswr.2025.395186.669938 FA Samira Hemmati Department of Soil Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran Kamran Moravej Department of Soil Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran Ahmad Golchin Department of Soil Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran Mohammad Sadegh Askari Department of Soil Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran Journal Article 2025 05 12 Land use change can significantly influence soil properties, both directly and indirectly, with important implications for soil health and agricultural productivity. This study aimed to assess the effects of converting barren land into paddy fields and olive orchards on soil physical, chemical, and biological properties in the Loshan region of Guilan Province, Iran. The results showed that land use change led to notable improvements in soil quality. Physically, the conversion increased clay and silt content while decreasing sand content compared to barren land. The mean weight diameter of soil aggregates increased significantly 3.73 times in olive orchards and 1.53 times in paddy fields indicating improved soil structure. Chemically, soil fertility improved. The levels of organic carbon, total nitrogen, and key nutrients such as Phosphorus and Potassium were significantly higher in the cultivated lands. Organic carbon content was approximately 3.9 times higher in paddy fields and 2.8 times higher in olive orchards than in barren soils. Biologically, the soil's microbial activity increased. Microbial biomass carbon rose nearly fourfold in paddy fields and nearly threefold in olive orchards. In summary, converting barren land to paddy fields and olive orchards positively affected soil health by improving its physical, chemical, and biological properties, thus supporting higher agricultural productivity and long-term natural resource sustainability. Land use change can significantly influence soil properties, both directly and indirectly, with important implications for soil health and agricultural productivity. This study aimed to assess the effects of converting barren land into paddy fields and olive orchards on soil physical, chemical, and biological properties in the Loshan region of Guilan Province, Iran. The results showed that land use change led to notable improvements in soil quality. Physically, the conversion increased clay and silt content while decreasing sand content compared to barren land. The mean weight diameter of soil aggregates increased significantly 3.73 times in olive orchards and 1.53 times in paddy fields indicating improved soil structure. Chemically, soil fertility improved. The levels of organic carbon, total nitrogen, and key nutrients such as Phosphorus and Potassium were significantly higher in the cultivated lands. Organic carbon content was approximately 3.9 times higher in paddy fields and 2.8 times higher in olive orchards than in barren soils. Biologically, the soil's microbial activity increased. Microbial biomass carbon rose nearly fourfold in paddy fields and nearly threefold in olive orchards. In summary, converting barren land to paddy fields and olive orchards positively affected soil health by improving its physical, chemical, and biological properties, thus supporting higher agricultural productivity and long-term natural resource sustainability. https://ijswr.ut.ac.ir/article_104846_b0c6f356f68612c3a4349d80ad02bd16.pdf