Management implications for a poplar phytoremediation plantation

Phytoremediation with poplar trees has recently shown promise for remediating many types of contaminants. However, the management of phytoremediation plantations has not been optimized for maximum remediation performance. It was hypothesized that increased management of a poplar plantation can improve poplar root development and reduce the time to gain hydraulic control of a landfill leachate plume. In order to sufficiently understand the potential of increased management to increase hydraulic control of a ground water plume, a field study site was used. This site, located in Manhattan, Kansas, focused on the impacts of tree management by exploring the differences in nutrient applications. A plantation composed of two varieties of poplar trees (Populus L.) was planted in the spring of 2006. Half of the trees received only fresh water and the other half received a treatment of 50% fresh water and 50% lagoon effluent. Measurements taken included tree height, trunk diameter, tree crown area and soil moisture (tensiometers and neutron probe). After receiving treatments over the course of the summer, the data indicated that there were no significant differences in the trees receiving lagoon treatments and the trees receiving only fresh water. The expected irrigation treatment effect was most likely masked by the inherent high fertility of the site. However, all trees were effective at reducing soil moisture. It is thought that after several years of growth the trees receiving nutrient applications will be more effective at drying out the soil as the existing soil nutrients are utilized. In addition to phytoremediation applications, this management strategy can be used to reduce the ecological impacts of animal feeding operations.