Sustainable Management and Productive Utilisation of Acid Soils: A Critical Synthesis of Amendments, Biological Adaptation and Systems-Level Trade-offs

Abstract

Acid soils constrain crop production through interacting chemical, biological and physical processes rather than low pH alone. Aluminium and manganese toxicity, depletion of base cations, restricted phosphorus availability, impaired root exploration and shifts in soil biota can occur at different depths and with markedly different severity among soils. This critical narrative review evaluates strategies for the sustainable management and productive utilisation of acid soils, with emphasis on agricultural topsoils and subsoils, amendment choice, biological adaptation, integrated nutrient management, implementation constraints and environmental safeguards. Peer-reviewed literature published from January 1990 to 30 May 2026 was selected through transparent searches of accessible scholarly indexes, supplemented by citation chasing and verification of bibliographic records and digital object identifiers. The evidence is strongest for correctly diagnosed, crop-specific liming of the cultivated layer. Nevertheless, average responses conceal substantial heterogeneity associated with initial acidity, buffering capacity, amendment quality, placement, soil depth, water regime, crop sensitivity and co-limiting nutrients. Gypsum can improve calcium supply and alleviate aluminium constraints below the limed layer, but it is not a substitute for acid neutralisation and can redistribute magnesium or potassium. Organic amendments and biochar may complex aluminium, supply nutrients and improve buffering, yet their effects depend on composition, dose, decomposition and contaminant control. Acid-tolerant crops, root traits and rhizosphere processes extend productive options but rarely remove the need to correct severe chemical constraints. The most defensible strategy is therefore a profile-based sequence: diagnose active and reserve acidity by depth, set a crop- and soil-specific target, apply quality-assured amendments at an effective placement and rate, correct nutrient imbalances, use adapted germplasm, retain organic resources and monitor re-acidification. Sustainability appraisal must include quarrying and transport, greenhouse-gas accounting, nutrient leaching, biodiversity, land-use change, affordability and amendment quality. Productive utilisation should prioritise already-cleared or degraded acid land and should not be used to justify conversion of intact acid-soil ecosystems. Long-term, depth-resolved and economically explicit field experiments remain the principal evidence need.