Subsoil Thickness Effects On Yield and Soil Water When Reclaiming Sodic Minespoil
- Thomas A. Oddie * and
- Arthur W. Bailey
Minespoil sodicity has the potential to limit plant growth and impede reclamation success on surface-mined land. A joint government/coal industry experiment was established near Highvale, AB, to determine suitable subsoil thicknesses (0, 55, 95, 135, 185, and 345 cm underlying 15 cm topsoil) for reclaiming sodic minespoil and maximizing production of an annual barley (Hordeum vulgare L.) cereal crop or a perennial alfalfa-smooth bromegrass (Medicago sativa L., Bromus inermis Leyss.) forage mixture. Barley and forage yields were lower on the 0-cm subsoil treatment than all other treatments. Yields for both crops increased as subsoil thickness increased to 55 cm. There was a consistent trend toward optimum yields on the 95-cm subsoil treatment, but the difference between 55 and 95 cm was not significant. The replacement of 55 to 95 cm subsoil plus 15 cm topsoil appeared sufficient to restore post-mine productivity to the potential achieved on surrounding agricultural land. Root depth under the forage mixture increased as total soil thickness increased, while increases under the cereal were not generally significant. The average effective root zone extended to about 85 cm under barley and 185 cm under alfalfa-smooth bromegrass. Average seasonal soil water within the effective subsoil root zone generally increased under barley and decreased under alfalfa-smooth bromegrass over time. Lower consumptive use of available soil water and a shallower effective root zone under barley contributed to accumulations of soil water above the subsoil/minespoil interface. Perennial forages appeared to be more effective in reducing soil water accumulations above the interface and promoting reclamation success of sodic minespoil.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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