The Determinants of Soil Quality: A Systematic Review

Abstract

Soil quality is shaped by interdependent pedological conditions, climate, terrain, land use, and management, yet the strength and direction of responses differ across functions and assessment frameworks. This systematic literature review critically synthesizes 50 distinct, DOI-traceable primary journal reports published from 2022 to 2025, applying PRISMA-informed reporting principles and a narrative comparative synthesis. The evidence encompasses landscape conversion, erosion, soil texture and parent material, carbon and nutrient dynamics, tillage and cover cropping, organic amendments, salinity and irrigation, reclamation, and microbial processes. Long-running field trials indicate that soil structure may improve without corresponding increases in carbon stocks across the measured 0-20 cm soil layer, whereas short-term cover-crop responses can be muted under drought. Biological recovery following organic restoration can coexist with persistent contaminant concerns, and indices that emphasize chemical fertility can underrepresent structural or ecological constraints. This review distinguishes external determinants from indicators used to measure their consequences, compares treatment duration and soil depth, and identifies uncertainties arising from observational designs and non-equivalent soil-quality indices. More comparable, multi-functional, depth-resolved and longitudinal evidence is required to guide context-specific restoration and management decisions.