Boron accumulation and tolerance of hybrid poplars grown on a B-laden mixed paper mill waste landfill.
Paper mill wastes are a mixture of by-products from pulp production and on-site energy production, consisting of paper mill sludge, ash and cinders. Landfilling of these highly boron (B) and heavy metal laden waste products carries environmental risks. Poplars have been successfully employed in the phytomanagement and hydraulic control of B contaminated sites. Here, we assess the performance of hybrid poplars on a paper-mill waste landfill, investigate the accumulation of B by the trees and explore the relationship between local-scale root growth and substrate properties. Leaf and root tissue samples were collected on three plots and analyzed for their chemical properties and root traits. Additionally, we sampled four soil cores in the vicinity of each of the trees and determined chemical and physical properties. Using a principal component analysis followed by a cluster analysis, we identified three substrate types. This method delineated the soil effects on tree survival and growth, although correlations with individual soil element concentrations were weak. Despite signs of B toxicity in some leaves, B was not the key limiting factor for poplar growth. Instead, Ca deficiency caused by a Mg:Ca imbalance was the primary reason for the poor performance of some trees. Root growth was not limited by toxicity effects of soil contaminants. Our results show that hybrid poplars perform well under the harsh growing conditions on a multi-contaminated, B-laden substrate in a hemiboreal climate. Exploiting the differences in the performance of the four clones in relation to the soil types, could increase the success of revegetation on this and other landfills.
Institute of Terrestrial Ecosystems, ETH Zürich, Universitätsstrasse 16, 8092 Zürich, Switzerland. rainer.rees@env.ethz.ch
Rainer
R
Rees
Brett H
BH
Robinson
Christopher J
CJ
Rog
Andreas
A
Papritz
Rainer
R
Schulin
D001895:Boron / Q000493:pharmacokinetics* / Q000633:toxicity; D002678:Chimera; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development; D032107:Populus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D012037:Refuse Disposal; D012044:Regression Analysis; D012989:Soil Pollutants / Q000493:pharmacokinetics* / Q000633:toxicity; D014922:Wisconsin
D012989:Soil Pollutants; D001895:Boron