Soil quality assessment based on MCDA–GIS hybrid approach for sustainable hazelnut farming under humid ecosystem environment

Agricultural soil quality has recently become an interesting topic for research with increased awareness in agricultural sustainability reduced agricultural lands due to urbanization and rapid population growth, and negative environmental effects. Hence, the present study aimed to investigate the soil quality properties of the hazelnut production areas which have great economic value for the Eastern Black Sea Region. We performed an analytical hierarchical process and standard scoring function (linear—L and non-linear—NL) on 29 soil indicators including physical, chemical, biological, plant nutrient, and heavy metal pollution parameters. In addition, eight indicators were determined by minimum data set and evaluated with the Weighted Linear Combination approach to find out the soil quality index of hazelnut cultivation lands. Our statistical analysis revealed no statistically significant differences between the soil quality index (SQI) values of the minimum data set (MDS) and the total data set (TDS). The spatial distribution maps obtained by both clustering analysis and geostatistical analysis showed very similar values and patterns between SQITDS-L and SQIMDS-NL. In addition, according to SQITDS-L and SQIMDS-NL, it was detected that more than half of the research area had low to very low soil quality (64.9–62.5%). The rates of high soil quality areas were 7.6% for SQITDS-L and 8.5% for SQIMDS-NL. Besides, moderate soil quality areas constituted nearly one-third of all areas for both indices.