Soil Moisture Determination

Printer-friendly version

Soil Core

Use the following table when determining soil moisture levels by hand. Know your soil type (see the Maps in your DNMP for soils information) and pick an area that is representative of the entire field. Measure the soil moisture from the top 6 inches of the soil profile. Take a representative handful and gently squeeze it into a ball in your hand. Follow the descriptive guidelines on the following table to determine the soil moisture %. This might take some practice, so having a method of verification (soil moisture determination equipment) the first few times is recommended. Replication of this process is recommended at multiple locations in each field.

Available Moisture in the Soil Sands and Loamy Sands Sandy Loam and Fine Sandy Loam Very Fine Sandy Loam, Loam, Silt Loam, Silty Clay Loam, Clay Loam, Sandy Clay Loam Sandy Clay, Silty Clay, Clay
< 25% Soil Moisture Dry, loose and single-grained; flows through fingers. Dry and loose; flows through fingers. Powdery dry; in some places slightly crusted but breaks down easily into powder. Hard, baked and cracked; has loose crumbs on surface in some places.
25-50% Soil Moisture Appears to be dry; does not form a ball under pressure. Appears to be dry; does not form a ball under pressure. Somewhat crumbly but holds together under pressure. Somewhat pliable; balls under pressure.
50 - 75 % Soil Moisture Appears to be dry; does not form a ball under pressure. Balls under pressure but seldom holds together. Forms a ball under pressure; somewhat plastic; slicks slightly under pressure. Forms a ball; ribbons out between thumb and forefinger.
>75% Soil Moisture Sticks together slightly; may form a weak ball under pressure. Forms a weak ball that breaks easily, does not stick. Forms ball; very pliable; slicks readily if relatively high in clay. Ribbons out between fingers easily; has a slick feeling.
100% Field Capacity On squeezing, no free water appears on soil, but wet outline of ball on hand. On squeezing, no free water appears on soil, but wet outline of ball on hand. On squeezing, no free water appears on soil, but wet outline of ball on hand. On squeezing, no free water appears on soil, but wet outline of ball on hand.
Above Field Capacity Free water appears when soil is bounced in hand. Free water is released with kneading. Free water can be squeezed out. Puddles: free water forms on surface.