Slake test

Technical articles - Soil erosion, Soil regeneration, Water management

© Tarn Chamber of Agriculture

It is a method to assess the structural stability of a soil, that is to say the ability of soil aggregates to resist degradation, notably under the effect of rain or excess water.

Why perform a slake test?

Soil stability is an indicator of the biological activity it contains: the bonds between soil particles are constantly renewed by biological processes. The stronger this activity, the stronger the bonds. Tillage has a major impact on soil quality, as it physically disturbs the soil and leads to the decomposition of organic matter. Over time, tillage reduces soil biological activity and thus the ability of soil organisms to stabilize soil aggregates.

Principle of the slake test

It is a qualitative method consisting of placing a soil clod in a container filled with water, on a piece of mesh, and visually observing how soil particles detach and the color of the water. The following protocol does not correspond to the scientific protocol, but rather to one intended for the field and farmers.

Equipment:

• 2 large glasses
• 2 meshes
• 2 soil clods
• stopwatch (if needed)

Quanti-Slake test

It is a quantitative method, derived from the Slake test, developed by Frédéric Vanwindekens. The soil clods are weighed during their disintegration.

Protocol

1. Sample collection: using a spade, collect a soil sample at a depth of 10 cm. Keep a volume of about 5 cm per side that holds together
2. Drying: let the sample air dry for at least one month
3. Test preparation: place the dried sample on a piece of chicken wire in a container filled with water
4. Measurement: use a scale to continuously weigh the sample while it disintegrates in the water
5. Analysis: create a graph from the scale data; calculate indicators from the graph to assess soil structural stability
6. Comparison: compare the results with other slake-test curves or indicators to determine if the soil is more or less stable than other soils