Potential of Biological Materials for Coal Mine Reclamation

Coal is mined for energy production around the world, and while production is declining in developed countries, it remains a common energy source in developing nations. Once the coal mine is exhausted, these large scale disturbances must be reclaimed to provide productive land for communities. This research investigates use of humic materials and arbuscular mycorrhizal fungi to enhance soil reclamation and plant productivity and add to knowledge of coal mine reclamation that can be applied to legacy, current, and future coal mines globally.

Globally natural and commercial biological products are increasingly being developed and used to improve soil quality. Some biological materials are composed of humic substances, a series of hydrophilic and acidic natural compounds with high molecular weight. Humic substances are of ecological importance as they act as a reservoir of organic carbon for global carbon cycling and can transport metal ions in the environment. They are currently used in agriculture and horticulture to improve soil quality and increase plant growth and crop yields and are considered suitable amendments for metal remediation in soil and water systems. The overall mechanism of humic acids, the primary component of humic substances, on soil remediation and reclamation and plant growth is not well understood. Nano humus is a material important in China and has potential for use in reclamation. The product is applied in the soil, can quickly complex metals in soil, effectively increase soil organic matter content, prevent and control soil borne diseases. Its application to large scale reclamation work is needed. 

Rhizosphere microbial activity is a principal factor determining availability of nutrients to plants and significantly influences plant health and productivity. Mycorrhizae are normally the major organisms for soil-plant interactions and can enhance water and nutrient acquisition. Fungi in the arbuscular mycorrhizal symbiosis promote plant uptake of major macro and micro nutrients and of water in the root system and consequently promote overall plant growth. Arbuscular mycorrhizal fungi positively influence soil quality by increasing aggregate stability, slowing organic carbon decomposition, and regulating enzyme activities. Arbuscular mycorrhizal fungi have been studied under controlled conditions, with few field studies conducted. The relative effectiveness of nano humus to arbuscular mycorrhizal is not known.