Residual effects of topsoil replacement depths and organic amendments on soil organic carbon levels of reclaimed wellsites

摘要

The reclamation success of abandoned wellsites in agricultural areas depends on their capacity to sustain levels of soil quality similar to those which existed prior to soil disturbance. A study conducted from 1997-2000 examined the effect of four (0,50, 100 and 150%) topsoil replacement depths (TRD) and five amendment treatments [compost, manure, alfalfa (Medicago saliva L.) hay, wheat (Triticum aestivum L.) straw, check) in the reclamation of three natural gas wellsites in south-central Alberta. In 2007 (10 yr after establishment) the three wellsites were sampled to examine the residual effects of reclamation treatments on soil organic carbon (SOC). The compost-amended plots (averaged over all TRDs) in 2007 maintained higher SOC than the straw and check plots (by 11-15%). The results showed that where topsoil is scarce (e.g. in the reclamation of older wellsites) initial investment in organic amendments can have a residual effect on soil quality, as indicated by SOC.