Use of pulp mill biosolids to stimulate forest plant growth on an industrial footprint with marginal soil

Abstract

Land application of biosolids may be an effective strategy to improve soil quality and better support the establishment of native vegetative cover on an industrial footprint with marginal soil. Biosolids can influence the C sequestration potential of impacted soils at the onset of reclamation activities by facilitating soil development processes and enhancing primary productivity, thereby leading to an increase in soil organic carbon (SOC) accumulation.The objective of this study was to examine the ameliorative effects of biosolids originating from a regional pulp and paper company on soil and vegetation development at a reclaimed airstrip in NW Alberta with limited topsoil replacement. Three biosolids application treatments (0 [control], 6.2, and 15.5 T ha−1) were established and vegetation was monitored by measuring percent cover and woody species density, height, biomass, and total nitrogen in aboveground biomass. The effects of biosolids on soil bulk density, various chemical properties including total organic carbon (TOC), nitrate (NO3), phosphorous (P), soil organic matter (SOM) and vegetation growth and establishment were evaluated over five growing seasons after initial application.One-time application of biosolids at 15.5 T ha−1 decreased soil bulk density, significantly increased other soil chemical properties (e.g., TOC, NO3, SOM), and improved native species vegetation establishment and growth significantly over the five growing seasons. These findings have implications for improving the efficiency and reducing the cost of reclamation in industrial footprints with marginal soil properties (high bulk density, low total organic carbon and nitrogen) using a by-product from forestry companies to ameliorate the soils