The effects of coal seam gas infrastructure development on arable land in southern Queensland, Australia: field investigations and modeling

. The production of coal seam gas (CSG) in Australia is set to increase, driven by increasing global demand for energy and in response to the transition to a lower carbon economy through greater use of gas for electricity generation. Despite the many economic benefits delivered by the CSG industry, concerns have been raised over the potential environmental impacts associated with CSG production, particularly the long-term effects on the soil resource. Therefore, this work was conducted to: (1) assess the extent of damage to agricultural soil caused by the various elements of CSG development and (2) estimate the likely impact of soil compaction, caused during establishment of CSG infrastructure, on crop productivity. The study was undertaken using a paired-sites approach by comparing measurements conducted on selected soil properties in areas around and including well-head sites with measurements in neighboring agricultural fields. These spatial areas are referred to as “lease” and “field” areas, respectively. Measurements were used to guide parameterization and application of the Agricultural Production Systems Simulator (APSIM) model to assess the likely effects of changed soil conditions on crop productivity. To achieve this, the APSIM model was used to simulate wheat ( L.) yields for 115 years on Grey Vertosols in the Darling Downs region of Queensland. Simulations were conducted with soil properties representing: (1) field area conditions not affected by CSG activities, (2) lease area conditions in which soil had been impacted by CSG activities during the development phase, and (3) lease area conditions where soils had been rehabilitated. Results showed that soil compaction within lease areas in the top 300 mm of the profile was approximately 15% higher compared with field areas (p -3 for the 0 to 350 mm and 350 to 700 mm depth intervals, respectively, are suggested as references for CSG-rehabilitated soil. These critical values may be used as guidance until further studies are undertaken. The assessment of soil chemical properties indicated that these were affected to a lesser extent by the establishment of CSG infrastructure. However, a general requirement is careful manipulation of sodium-rich subsoil and avoidance of soil blending during reinstatement operations. The dataset acquired and the simulation approach employed in this study can be used to further develop soil management guidelines relevant to the Australian CSG industry. Cost-benefit analyses of soil management practices for reinstatement, development of soil quality standards, and industry best management practices are required.