Beyond soil quality mapping: integrating fertility indices and TOPSIS for sustainable land management in arid areas

Abstract

Introduction Soil ranks among a nation’s most valuable natural assets, and reliable understanding of local soil resources is essential for effective land-use planning and rural development. Methods This study set out to evaluate soil fertility and quality across different land management practices in Sohag Governorate, Egypt, combining geoscience methods with the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). GPS-located sampling covered 34 points spanning old cultivated, recently cultivated, and bare soils, and standard laboratory procedures were used to determine their physical and chemical properties. TOPSIS was then applied to each sample to derive a current fertility status and an overall soil quality index (SQI). Results and discussion The soil aggregate stability index (SASI) averaged 1.81 (range 1.14–2.57) in old cultivated soils, 1.36 (0.2–3.62) in recently cultivated soils, and 0.4 (0.08–1.67) in bare soils; the soil-sealing index (IB) averaged 1.32 (0.17–4.35), 1.40 (0.11–5.10) and 0.57 (0.44–1.09) for the same three groups, and the Forestier index (IF) averaged 1.74 (0.46–4.39), 1.69 (0.36–5.28) and 1.03 (0.66–1.64). Four fertility classes emerged from this analysis, occupying 4.21, 15.22, 15.36 and 65.21% of the surveyed land. SQI itself ranged from 36.36 to 52.00% in old cultivated soils, 28.13–53.57% in recently cultivated soils, and 2.94–25.00% in bare soils, resolving into three quality regions: a moderate-quality zone spanning old and recently cultivated land (55.64% of the study area), a poor-quality zone across parts of the recently cultivated and bare soils (35.47%), and a very-poor-quality zone concentrated in bare soils (8.89%). Conclusion Together, these results provide decision-makers and land managers a practical, spatially explicit basis for prioritizing soil conservation work. In arid agricultural contexts, identifying and mapping fertility-depleted zones in this manner creates the evidence base necessary for targeted rehabilitation, which is crucial for closing the yield gap, reducing dependence on food imports, and enhancing national food security.