A simplified and rapid technique to determine an aggregate stability coefficient in coarse grained soils

• We propose a new method to determine aggregate stability in coarse grained soils (WRB: Leptosols; USCS: GP-GM).
• The aggregate stability coefficient (ASC) is a first-time presentation of a technique to be applied to coarse grained soils.
• The ASC is time saving and cost effective compared to existing standards for fine grained soils.
• The ASC was tested against a standardized method for fine grained soils using 167 soil samples.

Soil aggregation determines soil structure and hence influences soil physical, chemical and biological processes. To express soil aggregate stability a variety of indices are discussed in literature. However, the available measures are more suitable to soils with low stone contents while there is currently no established method for stone-rich soils.On an Alpine slope where soil texture is dominated by particles > 2 mm in diameter, 108 soil samples were collected from the 0–20 cm layer and split into 0–10 cm (n = 108) and 10–20 cm (n = 59) layers, resulting in 167 analyzed subsamples. Two methods were used to determine soil aggregate stability: (i) A ‘classical’ wet sieving approach as basis for calculating the mean weight diameter (MWD), and (ii) a new technique (aggregate stability coefficient—ASC), adapted to soils with high stone contents and reducing work effort to a minimum.The newly introduced ASC correlated closely with the MWD at all considered soil depths (0–20 cm layer: r = 0.84, R2 = 0.85, p < 0.01, n = 108) showing a comparable precision.The ASC is a useful aggregate stability indicator for stone-rich soils which can be used to evaluate near-surface soil stability, particularly in mountainous environments prone to erosion processes.