|MCGREW, REBECCA - North America Coal Cooperation|
Submitted to: Land Degradation and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2018
Publication Date: 11/22/2018
Citation: Adeli, A., Brooks, J.P., Read, J.J., McGrew, R., Jenkins, J.N. 2018. Post-reclamation age effects on soil physical properties and microbial activity under forest and pasture ecosystems. Land Degradation and Development. 50(1):20-34. https://doi.org/10.1080/00103624.2018.1546868.
Interpretive Summary: Mining activities deplete soil organic C due to topsoil loss and by mechanical mixing of soil horizons during material handling and removal. Reclamation of coal mine soils has the potential to restore soil quality and productivity over time. The primary purpose of reclamation of disturbed coal mine soils is restoring the land to pre-mining condition. Measurement of soil physical and biological properties are necessary for understanding soil restoration and development over time. Generally, coal mine soils right after reclamation are compacted and have higher bulk density and lower water infiltration and hydraulic conductivity than undisturbed/unmined soils. Increased organic matter is an important indicator and has a key role on improvement of physical and biological properties of coal mine soils. Several studies have reported that organic matter content of a soil at the 0- to 20-cm depth 13 years after reclamation was about 2.5 fold higher than that of 1year-old soils. The effects of reclamation age and land use on soil physical and biological properties have been reported mainly in temperate and cold climatic conditions and dry environment. However, the effects of chronosequence reclamation on soil physical properties and microbial activity have not been documented in southeastern U.S. having a subtropical climatic conditions. The objectives of this study were to determine the effects of reclamation age and vegetation types on soil physical properties and microbial activities in reclaimed mine soils following coal mining in southeastern U.S. ecosystem.
Technical Abstract: The study was conducted to evaluate soil quality changes at different reclamation ages under both forest and pasture ecosystems. Chronosequence sites covering successional reclamation ages in the ranges of 1 year, 4 years, 8 years, 11 years, and 13years old were selected from both forest and pasture ecosystems. Core samples were collected from reclaimed and unmined/undisturbed sites at the 0- to 15-cm depth using GPS coordinate and analyzed for soil quality indicators such as bulk density, water stable aggregate and total organic C. Water infiltration and compaction were directly measured in the field. Soil water stable aggregate and water infiltration were increased but soil bulk density and compaction decreased with increasing chronosequence reclamation. Since soil organic C was positively correlated to chronosequence reclamation (r2 =0.94 and P =0.0033) and aboveground dry matter (r2 = 0.96 and P = 0.0022) , changes in soil physical properties most likely were related to the accumulation of soil organic C and microbial activity over time. Averaged across reclamation age, compaction index and bulk density were greater by 18% and 14% for the pasture land as compared to forest ecosystem. Enzyme activity was depressed in all reclaimed soils as compared to un-mined forest ecosystem. However 11 years after reclamation , bacteria population level in soils appeared to reach a level similar to unmined soils. Results indicate chronosequence reclamation was the main driving components in development of soil biophysical indicators through accumulation of organic C in a humid subtropical climatic condition in Mississippi.