Evaluation of Populus and Salix Continuously Irrigated with Landfill Leachate II. Soils and Early Tree Development

Abstract

Soil contaminant levels and early tree growth data are helpful for assessing phytoremediation systems. Populus (DN17, DN182, DN34, NM2, and NM6) and Salix (94003, 94012, S287, S566, and SX61) genotypes were irrigated with landfill leachate or municipal water and tested for differences in 1) element concentrations (P, K, Ca, Mg, S, Zn, B, Mn, Fe, Cu, Al, and Na) of a topsoil layer and a layer of sand in tanks with a cover crop of trees or no trees and 2) height, diameter, volume, and dry mass of leaves, stems, and roots. Trees were irrigated with leachate or water during the final 12 wk of the 18-wk study. Differences in most soil element concentrations were negligible (P > 0.05) for irrigation treatments and cover main effects. Phosphorous, K, Mg, S, Zn, Mn, Fe, and Al concentrations were greater in topsoil than sand (P = 0.0011 for Mg; P < 0.0001 for others). There was broad variation between genera and among clones for all growth traits. The treatment × clone interaction governed height, volume, and root dry mass, with (94012, SX61), (NM2, S566, SX61), and (S287, S566) exhibiting the greatest levels, respectively, following leachate application. Given the broad amount of variability among and within these genera, there is great potential for the identification and selection of specific genotypes with a combination of elevated phytoremediation capabilities and tree yield. From a practical standpoint, these results may be used as a baseline for the development of future remediation systems.

KEY WORDS:

• phytoremediation
• poplar
• willow
• edaphic properties
• tree volume
• tree biomass

ACKNOWLEDGMENTS

We thank Jud Isebrands (Environmental Forestry Consultants, LLC) and Don Riemenschneider (USFS) for advice during the planning and execution of the study, along with Timothy Volk (SUNY ESF) for supplying the Salix cuttings. We are indebted to Jill Zalesny (Iowa State University) for pivotal discussions about the interactions among soil science, plant physiology, and plant genetics. In addition, we are grateful to Steven Rock (US EPA) for insightful technical reviews and suggestions. Also, we appreciate the review of earlier versions of the manuscript from Robert Bridges, Mark Coleman, David Coyle, Deahn Donner, Neil Nelson, Adam Wiese, and Jill Zalesny.