HYPROP 2 Soil Moisture Release Curves

Creating soil moisture release curves has always been tricky. Traditional methods require a ton of work, are limited by a lack of data points, and can take several months just to complete a partial curve. And there’s never been an easy way to measure the range of soil water potential for an entire curve. Until HYPROP 2.

Simply accurate. Simply fast. Simply automated.

As soil scientists who have made hundreds of soil moisture release curves, we wanted an instrument that delivered greater accuracy. And we demanded an instrument that was automated. The HYPROP 2 takes only days vs. months to generate a soil water characteristic curve in the wet range, and it does this automatically.

Use the HYPROP 2 together with the WP4C (which measures the dry range), and you can create full, high-resolution moisture release curves across the entire range of soil moisture. Nothing else is capable of doing that—not at this level of detail.

Sampling ring flexibility

On top of all that, we designed the HYPROP 2 to automatically determine unsaturated hydraulic conductivity on undisturbed soil samples placed inside a standard 250 mL or 100 mL, 2 in diameter sampling ring. Used in tandem with the KSAT, it can a generate a hydraulic conductivity curve for any soil type. The resulting instrument winds up saving you time, hassle and worry.

Unrivaled accuracy

When it comes to soil water potential, measurements don’t get any more accurate or precise. That’s because the HYPROP 2 produces more data points (over 100 data points in the 0 to -100 kPa range), higher resolution data, more detail, and better information in its moisture release curves—information that is missed when using the traditional pressure plates or hanging water column methods.

The HYPROP 2 uses two precision mini-tensiometers to measure water potential at different levels within a saturated soil sample while the sample rests on a laboratory balance. Over time, the sample dries, and the instrument measures the changing water potential and the changing sample weight simultaneously. It calculates the moisture content from the weight measurements and plots changes in water potential correlated to changes in moisture content.