The influence of organic matter on aggregate stability in some British soils

TLDR

Aggregate stability was measured by wet‑sieving on 26 agricultural soils and correlated with soil texture, nitrogen, organic matter, iron, and cation exchange capacity, and further examined in 120 soils to assess relationships with organic matter and its fractions. Aggregate stability is strongly and exclusively correlated with organic matter and its related components, with no other soil constituent showing significance, indicating that organic matter is the primary driver of aggregate stability and can be used diagnostically to identify soils prone to structural instability.

Abstract

SUMMARY The stability of aggregates from 26 soils selected from agricultural areas was measured by wet‐sieving and the results correlated with sand, silt, clay, nitrogen, organic matter and iron contents and with cation exchange capacity. Highly significant correlations were obtained for the relationships between aggregate stability and organic matter and some properties associated with it. No other soil constituent investigated had a significant relationship with aggregate stability, indicating that organic matter is mainly responsible for the stabilization of aggregates in these soils. The relationships between aggregate stability, and organic matter content plus some of its component fractions were examined in more detail using 120 soils. Total organic matter, total carbohydrate and humic material extracted by various reagents each gave highly or very highly significant correlations with aggregate stability. However, whilst it was not possible to distinguish whether any one organic component was more important than another, the results indicate that soil organic matter levels can be used diagnostically to identify soils which may show problems of structural instability.