An evaluation of the impact of spoil handling methods on the physical properties of a replaced growing medium and on tree survival.

摘要

Excessive compaction in replaced soil can hinder establishment of trees on reclaimed surface mines. Compaction results primarily from excessive grading and/or excessive equipment traffic during soil handling (i.e. removal, stockpiling, transporting, placing, and grading). Mechanical resistance to penetration and bulk density are soil properties that can be measured to indicate the level of compaction. Bulk density is commonly used to measure soil compaction.; Reclamation cells were developed at the Starfire Mine to evaluate the impact of spoil handling methods on the properties of replaced growing media and ultimately on tree survival rate. The spoil handling methods evaluated included: compacted (the reclamation practices at mountaintop removal operations), loose-dumped (placement of growing medium material with trucks, but no grading), and struck-off (placement of growing medium material with trucks and minimal grading to shape the material) reclamation methods. Two methods to alleviate compaction were also evaluated. These included shallow tillage using conventional farm equipment with a subsoiler and deep tillage using a dozer with a ripping arm. Finally, the impacts of organic supplements on soil physical properties and tree survival rates were also evaluated.; From 1997 through 2001, penetration depth, penetration resistance, bulk density, and tree survival data were collected at the reclamation cells and correlated to determine the relationships that exist between soil compaction and tree survival. Regression models have been developed for each reclamation method evaluated using the collected data to predict tree survival rates on reclaimed surface mined lands. The regression models have been developed as a function of a single soil property, as a function of two soil properties, and as a function of three soil properties. The best fitting model has been recommended for each reclamation method studied, as well as for a composite of the data for all the reclamation methods. Procedures have been developed for handling soil/spoil during reclamation that can minimize compaction in the replaced growing medium. Finally, procedures have been developed for alleviating compaction in growing media on reclaimed and orphaned surface mined sites.