Soil aggregate stability: Comparison of two methods to evaluate the effect of agroecological cropping systems

Aggregate stability is considered an indicator of general soil quality due to its influence on the transfer and storage of liquids, solutes and gases in the soil, and thus on the soil’s functional capacity. A multitude of methods exist to assess it. Ideally, the selected method should be fast, easy to implement, inexpensive, reproducible, and able to detect differences in aggregate stability according to soil type, land use and agricultural management practices. However, few comparisons have been made between methods, making it difficult to determine whether using one offers any advantages over others. In this study, we compared two methods to evaluate the effect of agroecological cropping systems that differed mainly according to their rotation diversity, tillage intensity and exogenous nitrogen fertilisation: the fast wetting from the Le Bissonnais method (FW LB ), based on a particle-size distribution approach, which is frequently cited in the literature and standardised, and the recently developed fast wetting from the ASTAVIT method (FW ASTAVIT ), based on a dynamic surface-area evolution approach. To this end, aggregate stability measurements were carried out using each method on 12 fields of an experimental platform with homogeneous topsoil of clayed Cambisol soils, implementing the two different cropping systems. Both methods were relatively easy and fast to use, and their results were consistent with each other. Under these specific experimental conditions, the ASTAVIT method revealed significant differences in aggregate structural stability among systems, whereas these differences were not detected as significant using the FW LB method.