Small-Increment Electric Soil Sampler

Measurement of soil bulk density and volumetric water content in small (≤2-cm) depth increments is tedious and time consuming. Most methods require compositing several subsamples to control measurement error, and few are feasible with loose, dry soils. We developed and tested a sampler that uses an electric linear actuator to push an intact soil core out of the sampling tube. The soil core is maintained in an upright position and protected from fracturing by remaining inside the tube until sectioned with a cutting saw. Precise length increments and flat cuts are easily obtained, even in loose soils. Compared with existing incremental sampling technology developed 30 yr ago, the electric sampler reduced sample variability by half. The electric sampler requires only 7 min to collect a 26-cm core and section it into 2-cm increments, compared with 20 min per core with the older sampler.