Research Branch Report No. 294

Irrigation of tree plantations with recycled water in Australia: research developments and case studies.  H. T. L. Stewart, E. Allender, P. Sandell and P. Kube.  November 1983.  13 pp.  (unpubl.)


Recent developments in Australia reflect a general trend in drier countries to investigate all potential sources of non-potable water and, where possible, to use them in preference to potable sources. Also, schemes that currently discharge, or propose to discharge treated effluent to inland water systems are being critically reviewed. Thus, more attention is being focussed on schemes for recycling of effluents, especially those in which parks, recreation areas and plantation forests are irrigated with recycled water.

In Australia, research on the irrigation of trees with effluents commenced in the 1970s. Initial trials tested the survival and early growth of more than 60 native and exotic species irrigated with municipal effluent. Later work has concentrated on species from the genera Eucalyptus, Casuarina, Pinus and Populus, with the most detailed research being conducted with Pinus radiata D. Don (radiata pine). Aspects studied so far include the effects of effluent irrigation on tree production, wood quality, nutrition, photosynthesis, transpiration, and changes in soil properties.

There are now several projects across Australia where tree plantations are being irrigated with recycled water at an operational level. Described in this paper are three case studies: first, a 30 ha plantation of Populus spp. (poplars) established in 1980 in Victoria; second, a 20 ha plantation of Eucalyptus spp. (eucalypts) established in 1984 in South Australia; and third, a 25 ha plantation of E. camaldulensis Dehnh. (river red gum) established for fuelwood production in 1980 in the Northern Territory. The results of these projects to date, plus the results from other similar projects, demonstrate that well-planned and managed enterprises in which tree plantations are irrigated with recycled water can have important social, aesthetic and environmental benefits.

Also published:

Stewart, H. T. L., Allender, E., Sandell, P. and Kube, P.  (1985)  Irrigation of tree plantations with recycled water in Australia: research developments and case studies.  Symp. For. Util. of Munic. Wastewater and Sludge, Univ. Washington, Seattle, Washington, U.S.A., 25-28 June 1985.