Foliar Nutrient Composition of 19 Tree Species Grown on a PhytocappedLandfill Site

An alternative landfill capping technique ‘Phytocapping’ (establishment of perennial plants on a layer of soil placed over the waste) was trailed at Rockhampton, Australia, as it is eco-friendly, less expensive and socially acceptable. In this capping, trees are used as ‘Bio-pumps and Screens’ and soil cover as ‘Storage’. They together minimise water percolation leading to reduced leachate production. Twenty one tree species were grown on two depths of soil (700 mm and 1400 mm) and monitored for their growth and their ability to restrict water infiltration through the waste. A very common question raised by most scientist and engineers is growth and survival of tree species in a landfill environment. Hence to determine the conditions and health of the tree species, foliar and foliar litter nutrient concentrations were measured in all the tree species grown on the phytocapped landfill site. The 3 year-old trees showed slightly elevated levels of nutrient and this will continue as the trees mature and develop more roots. The trees in the 700 mm soil cover contained slightly higher leaf concentrations of nutrients due to the possible closer proximity of their roots to the waste.