A hydraulic coring system for soil-root studies

Reliable sampling of belowground components in the field is essential to agroecosystem research. Factors such as hardpans and dry soil conditions often increase sampling time and impede adequate sampling. The objective was to design and construct a soil coring system for rapid field sampling that minimized such limitations. Cores were extracted using a custom-made telescoping hydraulic cylinder device assisted by a hydraulic post driver mounted to the front of a small tractor. The telescoping device inserted the core tube into the ground, and the post driver was activated only when insertion had been slowed or stopped. The tractor's hydraulics powered the telescoping device and the post driver; both were controlled by the tractor operator. Custom driving heads were constructed to fit the upper end of core tubes to collect large-diameter soil samples (25 cm diam. by 0.6 m deep) or small samples (3.8 cm diam. by 1.0 m deep). As many as 14 large cores or 24 small cores per hour could be collected with this system. The coring system has been successfully used on various soil types and to sample both agricultural and forest sites for a number of experimental objectives.