Amendments to improve plant response under simulated water-limited conditions in diamond mine Anthroposols

Abstract

Development of Anthroposols for land reclamation requires consideration of a variety of factors to support plant establishment and growth. Water limitation is a key challenge when using mine waste as a growth medium, and these materials also have poor structure and lack organic matter and nutrients. These greenhouse experiments assessed effectiveness of treatments composed of hydrogel and organic amendments to increase plant establishment and growth under water-limited conditions in mine waste materials (crushed rock, lakebed sediment, and processed kimberlite) from a diamond mine in northern Canada. Amendments were hydrogel, peat, sewage, and soil, mixed with waste materials (substrates) at four application rates, and seeded with slender wheat grass (Elymus trachycaulus). One experiment assessed germination response with limited watering during germination, and the other experiment assessed growth response with adequate water during germination followed by restricted water. Substrate had the greatest effect on germination, with processed kimberlite and crushed rock being most successful, at least 10% higher than lakebed sediment. Sewage amendment resulted in the largest plants (mean 0.22 g in lakebed sediment, 0.40 g in crushed rock and processed kimberlite, 0.05 g no amendment); sewage had a limited effect on germination. Highest organic amendment application generally improved plant response. Hydrogel did not improve plant growth, although it increased germination up to 63% in processed kimberlite. Type of mine waste, amendment, and rate of application impacted germination and plant growth and can be altered to build a suitable Anthroposol for reclamation.