Strong legacy effect of peat composition on physicochemical properties of reclamation coversoil

Abstract

Incorporation of salvaged peat in soil cover designs for oil sands mine reclamation is a common practice. However, current peat salvage practices do not differentiate between peatland types or the botanical composition of peat. In this study, we characterized the botanical composition of natural peat and coversoil on reclaimed sites and examined the influence of botanical composition on the physicochemical characteristics of reclaimed coversoil. Peat samples were collected from 15 natural peatlands (bog, poor fen, and rich fen) and peat coversoils were sampled from six reclaimed sites in the Athabasca oils sands region. The botanical compositions (Sphagnum, wood Sphagnum, woody, and woody/moss herbaceous) of all samples were determined. We found that natural peatland types had different physicochemical properties, primarily driven by Sphagnum-dominated samples with a high carbon:nitrogen (C:N) ratio and low total exchange capacity (TEC) when compared with samples dominated by more woody/moss herbaceous material. Similarly, we found that coversoil with Sphagnum-dominated peat compared with woody/moss herbaceous peat had lower TEC, pH, and total nitrogen values and higher C:N ratios (∼40 vs. 20 for Sphagnum and woody/moss herbaceous, respectively). Our results indicate that physicochemical properties driven by botanical composition remain in coversoil 5 yr after placement.

Unravelling the genetic and functional diversity of dominant bacterial communities involved in manure co-composting bioremediation of complex crude oil waste sludge

“…Water was added to the compost mixture when necessary to maintain moisture level between 60-80%. pH changes and carbon dioxide evolution, used to monitor microbial activities, was also measured monthly using the closed jar method as described in previous studies [24,25]. At the end of composting, samples were collected from composts mixture for residual PAH analysis, in-situ PAH-degrading bacteria isolation and characterization, and metagenomic analysis.…”

Soil properties following borrow pit reclamation with insufficient topsoil amended with peat and biochar

“…The increase in EC in the LSS horizon relative to the USS in 2019 reflects the leaching of soluble salts from the overlying soil layer to this horizon over time (Rhoades, 1996). Wang et al (2014) Peat amendment has been shown to lower soil pH due to its acidic nature (Calver et al, 2019;Cao, 2019) and could explain the lower soil pH in plots amended with peat relative to biochar amended plots in our study. Our results corroborate those of Calver et al…”

Revegetation of disturbed land reclaimed with suboptimal topsoil replacement depth and organic amendments

“…Several organic amendments have been used in the reclamation of disturbed forest sites in Alberta, Canada. Peat is abundant in the oil sands region and is therefore commonly used in upland reclamation and revegetation projects (Calver et al, 2019; Errington & Pinno, 2015; Rowland et al, 2009). Peat supplies soil nutrients, such as nitrogen (N) and phosphorus (P) (Calver et al, 2019; Hemstock et al, 2010) and improves soil water holding capacity (Li et al, 2020; Moskal et al, 2001).…”

“…Peat is abundant in the oil sands region and is therefore commonly used in upland reclamation and revegetation projects (Calver et al, 2019; Errington & Pinno, 2015; Rowland et al, 2009). Peat supplies soil nutrients, such as nitrogen (N) and phosphorus (P) (Calver et al, 2019; Hemstock et al, 2010) and improves soil water holding capacity (Li et al, 2020; Moskal et al, 2001). While peat is commonly used in boreal forest reclamation, the majority of previous studies focused on the use of peat mineral mix on sites disturbed by oil sands mining (Dhar, Comeau, Naeth, Pinno, & Vassov, 2020a; Hahn & Quideau, 2013; Rowland et al, 2009).…”