Substrate and Topsoil Impact on Soil Water and Soil Temperature in Arctic Diamond Mine Reclamation

Amalesh Dhar,Valerie S Miller,M Anne Naeth,Sarah R Wilkinson

doi:10.3390/soilsystems6010012

Abstract

Soil properties in the Arctic are insufficiently explored and documented, particularly extensive monitoring of soil water and soil temperature over a period of time. Soil water and soil temperature are critical for understanding land surface and atmosphere interactions and are considered key factors for revegetation during mine reclamation. This study assessed how substrate and topsoil influenced soil temperature and soil water content at a reclaimed diamond mine in the Northwest Territories of Canada. Three substrates (crushed rock, processed kimberlite, and lake sediment) with and without topsoil were used. Mean air temperature changed little from year to year, although summer temperature showed a slightly increasing trend. Both annual and summer precipitation sharply declined over time. Soil water was influenced more by substrate than by placing 10 cm of topsoil on it. Processed kimberlite had greater water retention characteristics and water content than lake sediment and crushed rock substrates (significantly). Surface soil water content was lower with than without topsoil, suggesting that 10 cm of topsoil was not enough to influence it. Soil temperatures were not influenced by either substrate or topsoil. This study suggests processed kimberlite could be used as a substrate component for water and temperature management during reclamation of this extreme environment.

Highlights

Arctic ecosystems are characterized by extremely low air and soil temperatures, low water content on elevated surfaces, shallow depth to thaw, nutrient deficiencies, and short growing seasons [1,2,3,4]
The objectives of this study were (1) to assess how substrates with and without topsoil influenced soil temperature and soil water content at diamond reclamation sites in the Northwest Territories and (2) to ascertain how the substrates might contribute to greater reclamation success
Water retention differed by substrate, with processed kimberlite holding significantly more water than lakebed sediment and crushed rock at saturation (Figure 3)

Summary

Introduction

Arctic ecosystems are characterized by extremely low air and soil temperatures, low water content on elevated surfaces, shallow depth to thaw, nutrient deficiencies, and short growing seasons [1,2,3,4]. Large-scale disturbances such as diamond mining and gravel extraction can result in altered thermal, hydrologic, and/or nutrient regimes [7,8,9]. Land reclamation under such harsh environmental conditions and terrain is further challenged, as mining activities alter the shallow topsoil and subsoil, increase soil compaction by heavy equipment, and change other soil properties [10,11,12]. Overall mining exploration has intensified and increased almost 90%, mostly in the Arctic zone of Canada [14]

Objectives

Methods

Results

Discussion

Conclusion