Laboratory evaluation of soil amendments to limit structural degradation under a sequential irrigation with coal seam gas and rain water

Ali, Aram and Bennett, John mcLean and Marchuk, Alla and Watson, Caitlin (2018) Laboratory evaluation of soil amendments to limit structural degradation under a sequential irrigation with coal seam gas and rain water. Soil Science Society of America Journal , 82 (1). pp. 214-222. ISSN 0361-5995


Land amendment irrigation (LAI) has become an increasingly useful practice in addressing sodic and alkaline coal seam methane gas (CSG) water for irrigation purposes. However, there is a paucity of information pertaining to rapid dilution of soil solution under LAI management. This study investigated the ability of land amendment to buffer soils against structure degradation under sequential irrigation with CSG water (electrical conductivity [EC], 3 dS/cm; sodium adsorption ratio [SAR], 100 mmolc/L; pH 8.4) and rainwater in a highly smectitic black Vertisol (BV) and kaolinitic Oxisol (OX) soil. Stoichiometric quantities of gypsum and sulfur amendments were applied for the LAI process to reduce sodicity and alkalinity to a target of SAR <20 and HCO3= alkalinity =100 mg/L. Soils were irrigated with 10 ML/ha CSG water and 9 ML/ha rainwater in the sequence of 1 ML/ha and 0.9 ML/ha CSG water and rainwater events, respectively, using a 7.5 mm/h rainfall intensity. Saturated hydraulic conductivity was determined and reported as a reduction from initial conductivity. The collected leachates were used for subsequent measurements of pH, EC, SAR, and alkalinity at each event. Results suggested that LAI was inadequate to protect soil structure from more than three of the intensity–frequency duration events but sufficient for up to three events. This was considered positive evidence for LAI given the annual recurrence of such an event was one for the region. Additional gypsum application had no significant effect on protecting soil from further hydraulic reduction compared with LAI alone. The OX and BV behaved differently in terms of the observed hydraulic reduction, which was determined to be both a function of iron oxides (OX) and the effect of dilution, in contrast to the threshold electrolyte concentration. This highlighted that both the initial hydraulic conductivity and threshold electrolyte conditions are important in implementing LAI.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © Soil Science Society of America. Published online 8 Feb 2018.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - No Department
Date Deposited: 04 Sep 2018 05:08
Last Modified: 21 Sep 2018 05:00
Uncontrolled Keywords: hydraulic conductivity; electrolyte concentration; sodic soil; physical-properties; mined gypsum; natural-gas; infiltration; reclamation; efficiency; threshold
Fields of Research : 05 Environmental Sciences > 0503 Soil Sciences > 050304 Soil Chemistry (excl. Carbon Sequestration Science)
05 Environmental Sciences > 0503 Soil Sciences > 050305 Soil Physics
Socio-Economic Objective: D Environment > 96 Environment > 9614 Soils > 961404 Mining Soils
Identification Number or DOI: 10.2136/sssaj2017.07.0217

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