Assessing Fossil and New Carbon in Reclaimed Mined Soils
Soil organic carbon (SOC) pool in the reclaimed minesoils (RMS) is the mixture of coal C originating from mining and reclamation activities and recent plant-derived organic carbon (OC). Accurate estimates of OC pools and sequestration rates in the RMS are limited by lack of standard and cost-effective method for determination of coal-C concentration. The main objective of this project was to develop and test analytical procedures for quantifying pool sizes of coal-derived C in RMS and to partition organic C in RMS into coal-derived and newly deposited SOC fractions. Analysis of soil and coal artificial mixtures indicated that the {Delta}{sup 13}C method developed was very effective in estimating coal C added in the mixtures, especially soils under C4 plants. However, most of the reclaimed sites in Ohio are under C3 plants with range of {Delta}{sup 13}C signal falling within ranges of coal. The wide range of {Delta}{sup 13}C signal observed in minesoils, (i.e. -26 to -30 for plants and -23 to -26 for coal) limits the ability of this approach to be used for southeast Ohio minesoils. This method is applicable for reclaimed prime farm land under long term corn or corn soybean rotation. Chemi-thermal method was very effective in quantifying coal-C fraction in both soil-coal artificial mixtures and minesoils. The recovery of coal-C from the mixture ranged from 93 to 100% of coal. Cross-validation of chemi-thermal method with radiocarbon analysis revealed that chemi-thermal method was as effective as radiocarbon analysis in quantifying coal-C in RMS. Coal C determined after chemi-thermal treatment of samples was highly correlated with coal C concentration calculated by radiocarbon activity (r{sup 2} = 0.95, P < 0.01). Therefore, both radiocarbon activity and chemi-thermal method were effective in estimating coal carbon concentration in reclaimed minesoils of southeast Ohio. Overall, both coal-C and recent OC fraction exhibited high spatial and depth variation, suggesting that approaches used to obtain representative samples in undisturbed soils may not be effective in RMS sites. Analysis of coal-C fraction in RMS indicated that the contribution of coal C to SOC increased with increase in soil depth, accounting for up to 92% of SOC in the sub-soil. Our data indicated that land use and land management practices plays significant role in enhancing SOC sequestration in reclaimed mined lands.
- Research Organization:
- The Ohio State University Research Foundation
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FC26-04NT42208
- OSTI ID:
- 947102
- Country of Publication:
- United States
- Language:
- English
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Carbon Sequestration in Reclaimed Mined Soils of Ohio
CARBON SEQUESTRATION IN RECLAIMED MINED SOILS OF OHIO