Abstract
Soils in arid and semi-arid environments are threatened by salinization. A cost-effective and efficient way to reclaim saline land is through leaching. This will be most effective in situations where direct human impact is the cause for salinity, e.g., in environments affected by industrial use or land rehabilitation following mining. Irrigation, which is the most common means of achieving salt leaching, is not feasible for the reclamation of mine sites’ salt-affected soils located in remote areas, and thus, land reclamation largely relies on natural climatic conditions. This study was conducted to assess the effect of different climatic conditions of semi-arid environments on spatio-temporal salt leaching from brine-affected soil, and investigate the efficacy of the reduction of soil bulk density as a reclamation technique for saline land experiencing water scarcity. Three regions (represented by the Australian cities of Roma, Mount Isa, and Quilpie) representing semi-arid environments of Australia were selected, and their climatic scenarios (23 years) were applied to a validated HYDRUS-1D model. A brine-affected soil typical to Queensland, Australia, was chosen for this study. The investigations established that a greater number of individual high rainfall events resulted in a greater reduction of salinity in Roma (96%) and Mount Isa (93.31%) compared with Quilpie (58.75%), in which the soil salinity approached a level (<2 dS m−1) that was suitable for sustaining plant growth. Soil salinity reduced to 8 dS m−1 under the climatic conditions of the Quilpie region. This study also demonstrated that the success of salt leaching from a brine-affected soil is a consequence of a sensitive response to the depth of individual rainfall events rather than rainfall distribution and the total amount of rainfall, and is controlled by the physical properties of the soil. Where climatic conditions cannot solely assist with salt leaching, reclamation may be successful by reducing soil bulk density.
Highlights
Salinity affects approximately 400 Mha of land globally [1,2], almost 80% of which is affected by primary salinization, with the remaining 20% impacted by secondary salinization as a result of anthropogenic activities, such as agriculture, mining activities, as well as oil and gas extraction [3]
The spatio-temporal distribution of solutes to the depth of 30 cm, similar to the plant root zone in brine-affected soils located in semi-arid environments [35,50,51], is presented in Figures 2–5, and rainfall and evaporation patterns are indicated in Figures A1 and A2
In agreement with other studies [56,57], which concluded that a reduction in bulk density can reduce soil salinity and sodicity, this study indicated that a reduction of soil bulk density can decrease soil salinity and sodicity of the surface soil (Figures 6 and 7)
Summary
Salinity affects approximately 400 Mha of land globally [1,2], almost 80% of which is affected by primary salinization, with the remaining 20% impacted by secondary salinization as a result of anthropogenic activities, such as agriculture, mining activities, as well as oil and gas extraction [3]. In this context, Australia holds vast mineral and energy resources where significant ecological biodiversity or agro-ecosystems are situated [4]. Irrigation is a conventional method for salt leaching It is often not feasible for the reclamation of post-mining areas, due to their location in remote areas and a lack of water availability. Post-mining land reclamation (i.e., salt leaching) relies on natural climatic conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
