Land use change is a key driver of declining soil quality and ecosystem degradation. Forest ecosystems play a crucial role in maintaining environmental stability by providing favorable biotic and abiotic conditions. However, converting them to other land uses significantly alters the soil's structure and function. This study aims to evaluate the effects of land use and abandonment duration on the soil quality index (SQI) and analyze its spatial distribution in southern Zagros forests using advanced Kriging techniques.The research was conducted in the southern Zagros region (Dezpart County, Khuzestan Province, Iran). Four land use types were selected: a natural forest, and abandoned forests from understory agriculture with different lengths of time since abandonment, including three, ten, and twenty-five years. A total of 96 soil samples were collected from land used for various purposes. The SQI was computed using the integrated quality index equation. To analyze and map soil quality spatially, variogram modeling was performed using GS+ software to determine the best-fit model. Then, spatial interpolation was conducted using three kriging methods—ordinary, universal, and simple—within a GIS environment.The results revealed that soil quality was significantly influenced by land use (p < 0.05). The highest SQI value was observed in natural forest stands (0.63 ± 0.006), while the lowest value occurred in recently abandoned or fallow lands (0.26 ± 0.006). Of the variogram models, the linear model best fit the natural forest data; the exponential model best fit long- and short-term abandoned lands; and the spherical model best fit recently abandoned lands or fallow lands. Simple kriging yielded the best interpolation accuracy for natural forests (RMSE = 0.97) and long-term abandoned lands (RMSE = 1.01). Ordinary kriging performed best for short-term abandoned lands (RMSE = 1.18) and fallow lands (RMSE = 1.57).The findings reveal that land-use changes and the amount of time since abandonment significantly impact soil quality. Variogram modeling combined with kriging techniques effectively captured the spatial variability of SQI. These insights are valuable for prioritizing forest restoration efforts and guiding decisions about the management of natural resources in degraded forest landscapes.
Heydari M, Attarroshan S. Assessing the Effects of Land Use Change and Abandonment Duration on the Soil Quality Index Using Geostatistical Approaches in the Southern Zagros Forests of the Deh-Shikh Watershed. Wetland Ecobiology 2025; 16 (4) : 2 URL: http://jweb.ahvaz.iau.ir/article-1-1071-en.html