A Compression-Suction-Temperature (CST) Cell for Simulating the Physical Environment of Preemergent Seedlings
- K. Weaich,
- K. L. Bristow and
- A. Cass
Field investigations of the influence of soil physical conditions on seedling emergence are hampered by a lack of control and reproducibility of the physical variables. Controlled environment studies frequently fail to adequately simulate field conditions and seldom permit investigation of interactive physical conditions. In this paper, we describe a compression-suction-temperature (CST) cell designed to enable investigation of the response of preemergent seedlings to various strength and temperature regimes under unsaturated conditions. The cells allow independent control of soil strength, temperature, and matric potential. Suction within the CST cells is controlled by a hanging water column, soil strength by application of a uniaxial load, and soil temperature by a combination of heating and cooling of the upper and lower cell boundaries. Shoot growth in six cells was uniform, reflecting the minimal temperature discrepancies between cells. Temperature profiles typical of those experienced in the field were reproduced in the cells. Maize (Zea mays L.) shoot growth was responsive to temperature, with maximum elongation rates occurring at a constant temperature of 31.5 ¼. Application of 80 kPa of pressure (estimated shear strength of 42.0 kPa) to the seedbed stopped shoot growth, demonstrating the cell's capacity to alter the strength environment of the preemergent seedling.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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