Choosing Tree Genotypes for Phytoremediation of Landfill Leachate Using Phyto-Recurrent Selection

Abstract

Information about the response of poplar (Populus spp.) genotypes to landfill leachate irrigation is needed, along with efficient methods for choosing genotypes based on leachate composition. Poplar clones were irrigated during three cycles of phyto-recurrent selection to test whether genotypes responded differently to leachate and water, and to test whether the methodology had merit as a tool for plant selection during remediation. Fifteen below- and above-ground traits were evaluated. Twenty-five clones were tested in cycle 1, while the best 12 genotypes were evaluated in cycles 2 and 3. Eight clones were selected and subsequently tested in an in situ landfill study (cycle 4). Results from cycles 1, 2, and 3 are presented here. Overall, clones responded differently to irrigation treatments, with certain genotypes exhibiting better below- and above-ground growth with water than leachate. However, growth was greater with leachate irrigation for some clones. In addition, differences between treatments within clones decreased with days after planting (DAP). There were no treatment differences for number of leaves, height, and root length at the end of cycle 2 (45 DAP) or cycle 3 (30 DAP). These results detail the extensive variation in clonal responses to leachate irrigation, along with the need and efficacy of using phyto-recurrent selection to choose superior genotypes.

KEY WORDS:

• leachate irrigation
• wastewater treatment
• chloride stress
• clonal selection index
• short rotation woody crops
• Populus
• poplar

ACKNOWLEDGMENTS

We thank Bart Sexton (Oneida County Solid Waste Department) for supplying the leachate, along with Steven Ohm, Sherry Otto, and Susan Scobell-Watson (Wisconsin Department of Natural Resources) for assistance obtaining short-duration discharge permits for leachate application. 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 Edmund Bauer, Deahn Donner, and Nicanor Saliendra.

Notes

^a Leachate used in the current study.

^b Ranges based on 14 studies cited in Kjeldsen et al. (2002).