CarbonPump: Mathematics of the SuTiT flexible inner tube for efficient soil core sampling

CarbonPump: Flexible inner tube for soil cores

Abstract

Soil core samples underpin the evaluation of soil carbon stocks, an essential measurement to enable and support the establishment and operation of soil carbon natural capital markets. Soil cores are obtained by driving a tube as far as 1500mm into the ground to extract a vertically profiled sample. Robust, reusable sampling devices are essential to minimise sampling costs while reducing waste. The SuTiT is a customised inner tube designed to reduce waste while supporting rapid sampling across various dryland soils, including sandy and clay soils, which present unique challenges for extracting an intact core. The SuTiT provides for a flexible inner tube that, when closed, can be easily inserted into the solid outer tube and, when removed, relaxes naturally into a trough shape for easy access to the sample. A combination of kerf cuts and presses is used to achieve these features. This study group focussed on opportunities to increase the shelf-life of the SuTiT through exploration of the kerf patterns and their effect on the strength and bending properties of the tube.