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Jar of water test : to estimate the soil's texture

English
The water jar test method is used to approximate soil texture.
Photo: liz west (Muffet)
Jar of water

To which group does your soil belong?

Here's how to learn about the texture of your soil with the approximate jar of water test method.

Jar of water test (approximated method)

Place one or two cups of soil in a clear glass jar that holds about 1 litre and add water almost to the brim. Shake the mixture vigorously for a few minutes, then let it stand for at least 24 hours, because the clay may take several days to settle.

The mixture will gradually form layers, with sand on the bottom of the jar, silt in the middle and clay on top. Organic matter will float to the surface.

Tip: Do not move the jar during the test, as the soil layers will become suspended and must be allowed to settle again.

You can calculate the percentage of each element according to the depth of each layer.

% sand: (depth of the sand layer X 100) ÷ total depth of the soil in the jar

% silt: (depth of the silt layer X 100) ÷ total depth of the soil in the jar

% clay: (depth of the clay layer X 100) ÷ total depth of the soil in the jar

Jar of water test to estimate the soil's structure

Example:
The following jar contains about 35.7% sand, 28.6% silt and 35.7% clay. The soil has a clayey texture.

% sand = (2.5 cm X 100) ÷ 7 cm = 35.7%

% silt = (2 cm X 100) ÷ 7 cm = 28.6%

% clay = (2.5 cm X 100) ÷ 7 cm = 35.7%

Then you can use the following table to classify your soil:

Soil texture % sand % silt % clay
Sandy soil 70 or more 0 to 30 0 to 15
Silty soil 0 to 20 80 or more 0 to 15
Clay soil 0 to 45 0 to 40 25 or more
Loam 40 to 60 30 to 50 15 to 25

You can also use the touch test method to roughly assess a soil's texture. To get more information about the soil, it is best to turn to a laboratory analysis.