Aggregate stability and assessment of soil crustability and erodibility: I. Theory and methodology

Summary

This paper synthesises theory on soil aggregate breakdown, identifying four main mechanisms—slaking, differential swelling, raindrop impact, and physico-chemical dispersion—and their relative importance depending on rainfall characteristics and soil properties. The author proposes a unified measurement framework combining three wetting treatments with varying energy inputs to quantify fragment size distribution, enabling comparative assessment of soil susceptibility to crusting and erosion across different soils or climatic scenarios. The framework is designed for cross-sectional soil comparison rather than temporal monitoring of individual soil changes.

Regional applicability

The theoretical framework and methodology are globally applicable and widely adopted for soil characterisation in the United Kingdom and elsewhere. The aggregation mechanisms and assessment approach are relevant to UK arable and horticultural contexts, where soil crusting and erosion remain concerns in cultivated systems, particularly on structured clay and silt soils.

Key measures

Aggregate stability under three treatments (fast wetting, slow wetting, stirring after pre-wetting); fragment size distribution; assessment of soil crustability and erodibility

Outcomes reported

The paper reviews theories of aggregate breakdown mechanisms and proposes a unified methodological framework for measuring aggregate stability to assess soil susceptibility to crusting and erosion under different wetting conditions.

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