Theses and Dissertations Collection

With over 30,000 abandoned mines on USDA Forest Service land, efficient and affordable reclamation methods are needed to restore site productivity. Surface applied amendments, biochar, biosolids, and woodchips, provide cheap, sustainable solutions to promote re-vegetation. We investigated amendment effects on soil quality at a dredge tailings site in Northeast Oregon. Experimental plots of the three amendments were sampled bi-annually for two years to measure changes in soil properties and plant success. Available nutrients were analyzed by both field and laboratory methods. Soil moisture and temperature were monitored in-situ, and soil water holding capacity was measured. Results show increases in soil pH, cation exchange capacity (CEC), organic carbon, macronutrients, and plant growth. Although changes are pronounced in single amendment applications, the combination treatments induce more stable plant growth by providing a combination of soil quality improvements. Results suggest that surface amendment of biochar, woodchips, and biosolids for land reclamation of disturbed forest soils may be a promising method for remediation in droughty areas of the Pacific Northwest.