SECOND YEAR TRANSPLANT SURVIVAL ON CONSTRUCTED TEST PLOTS, QUESTA MINE, QUESTA, NEW MEXICO

Abstract

Chevron Mining Inc. established a revegetation test plot program to evaluate the potential cover depth, soil amendment, and planting treatments for reclamation of the Questa Mine rock piles. The Questa Mine is located near the Village of Questa, New Mexico at an elevation of approximately 2438 m. The test plot program consisted of constructing multiple test plots on 3 slope gradients: 3 horizontal units to 1 vertical unit (3h:1v slope gradient), 2h:1v slope gradient, and flat gradient (platform) test plots. Each test plot was constructed with 3 cover soil depth treatments over the existing rock pile material. These cover soil depth treatments included: no cover, 30 cm, and 90 cm of cover soil material. Soil amendment treatments varied between the sloped and flat gradient test plots. The sloped gradient test plots received treatments of forest soil mycorrhizal inoculant or no inoculant. The flat gradient test plots received treatments of phosphate fertilizer, forest soil mycorrhizal inoculant, or no amendment. After construction, each test plot was seeded, hydromulched, and planted with transplant tree and shrub seedlings. The transplanted tree seedlings consisted of 2 categories: nurse species and crop species. The nurse species consisted of fast establishing, short-lived species, which will shade and protect the crop species. The crop species consisted of multiple conifer species, which represent the post-mining land use plant community. The crop and shrub species were planted at a constant density, while the nurse species were planted at 2 different densities. Overall survival of all seedlings (2008) for platforms, 3h:1v, and 2h:1v slopes was 47%, 44%, and 46% respectively. Of all the treatments applied to the test plots, the one that consistently made a significant difference in survival was the depth of cover soil. The overall survival of all seedlings in 2008 for 0, 30, and 90 cm covers was 22%, 59%, and 58% respectively.