Native seed, soil and atmosphere respond to boreal forest topsoil (LFH) storage

PLoS One. 2019 Sep 16;14(9):e0220367. doi: 10.1371/journal.pone.0220367. eCollection 2019.

Abstract

During mining topsoil is salvaged and stockpiled until ready for reclamation, stockpiling can have detrimental effects on seed viability and soil quality. Research has assessed effects of salvage and placement depth of forest topsoil on plant community establishment, with little work on effects of storage, particularly in the boreal forest. Our research assessed boreal forest topsoil storage methods to determine effects on soil chemical and physical properties, native seed viability and germination and rhizome viability and emergence. Factors were topsoil stockpiling length, stockpile size, season of construction and soil texture. Four replicates of large and small stockpiles were constructed in the mineable oil sands, in northeastern Alberta. During construction seeds and rhizomes from a variety of native boreal plant species were buried within large (0.05, 1.0, 2.0, 4.0, 6.0 m) and small (0.05, 1.0, 3.0 m) stockpiles. Soil gas probes were installed at similar depths as seed and rhizomes were placed. Seeds and rhizomes were extracted eight months and sixteen months after construction; during that time soil samples were collected for various chemical analyses. Irrespective of stockpile size, the majority of species seeds and rhizomes buried below 1 m lost viability and did not germinate after eight months. Anaerobic soil conditions developed soon after construction and persisted at depths below 1.0 m in large stockpiles, and over time anaerobic conditions developed in smaller stockpiles. Only seeds of Geranium bicknellii and Dracocephalum parviflorum had a high survival rate in stockpiles; both species have hard seed coats and are physically dormant. Various soil nutrients increased in concentrations in their soluble forms after stockpiling. Direct placement of topsoil is a preferred soil handling technique; however, if topsoil has to be stockpiled increasing the surface area of stockpiles will help preserve some seed and rhizome viability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Atmosphere*
  • Forests*
  • Germination
  • Seeds*
  • Soil / chemistry*

Substances

  • Soil

Grants and funding

The following companies provided an unrestricted research grant to Dr M Anne Naeth to support the research addressed in this publication of her PhD student Dr Dean Mackenzie. This funding was used to cover direct costs of research. No funding was provided for the personal use or salary of the supervisor Dr Naeth: Syncrude Canada Ltd., Suncor Energy Ltd., Shell Canada Limited, Canadian Natural Resources Ltd., Total E&P Canada Ltd., and Fort Hills Energy LP by its General Petro-Canada Oil Sands Inc. (Multi Partner Grant Number G800001067). Dr Dean Mackenzie received a PhD scholarship from the Natural Sciences and Engineering Research Council (DDM). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.