Soil factors affecting vegetation establishment after sand mining on North Stradbroke Island

摘要

A study was undertaken to investigate causes for poor native vegetation establishment and erosion in rehabilitated sand dunes following sand mining at North Stradbroke Island, Australia. The problem was mainly associated with the use of topsoil from old rehabilitated sites from earlier mining ventures (designated as pre-mined topsoil) as opposed to using topsoil from unmined native areas (designated as unmined topsoil). The approach was to characterise the soil properties pertinent to soil erosion and measured poor plant growth from two rehabilitated areas of similar age but using the different topsoils, pre-mined and unmined. Results indicated that the greatest soil physical difference between the topsoil areas was the severity and frequency of water repellency (ratings 6-severe and 5- moderate to severe) that occurred in the pre-mined topsoil. Ca and Mg contents were also lower in the pre-mined topsoil area compared to that of the unmined topsoil, as was the lower Ca:Al ratio (<1), indicating a possible impact of poor cation balance on vegetation growth. Despite differences in surface stability and vegetation growth, soil carbon was not a differentiating factor between the unmined and pre-mined topsoil areas.