Use of soil transfer for reforestation on abandoned mined lands in Alaska

Abstract

Soil transfers, presumed to contain mycorrhizal fungal inoculum from a native plant community, were applied to rooted cuttings and volunteer plants of Populus balsamifera L. to improve their growth on an abandoned mined site in south central Alaska. The objectives of the study were to determine (1) if these soil transfers could be substituted for additional P fertilizer when applied with a base level of NP fertilizer to improve growth, and (2) if P added to treatments receiving a base level of NP fertilizer and soil transfer would suppress mycorrhizal formation. Physical dimensions of plants were measured near the beginning and end of each of two growing seasons. Several plants per plot were harvested at the end of year 2 to determine mycorrhizal formation, current growth, and leaf nutrient concentrations. Plant height was significantly increased only when soil transfer and additional P treatments were combined. Response to additions of P fertilization alone or soil transfer alone were not significantly different from each other. Current twig growth increased with either treatment alone or both combined. Soil transfer on cuttings resulted in more ectomycorrhizal formation than either the control or additional P. Leaf N concentrations on cuttings and volunteers increased when plants were treated with soil transfer. Similar growth responses were achieved by soil transfers or additional P, but mycorrhizal formation was improved with the soil transfer treatments. P added to the base level plus soil transfer did not suppress or improve mycorrhizal formation compared to that with soil transfer alone.