REPORT FROM DOWN UNDER

USING EARTHWORM SYSTEMS

Following a series of conferences and site visits, the authors conclude: "Clearly vermiculture is a technology whose time has come to Australia and New Zealand."

Clive Edwards and Jean Steele

Reprinted by permission from BioCycle July 1997 pages 63-64.

THERE is probably more interest and activity in vermicomposting in Australia and New Zealand than in any other region of the world. Both countries have a long history in earthworm research. It was here that the practice of introducing earthworms to agricultural fields that lacked them in order to increase grass yields was developed. Much data is known about Australian earthworm distribution as a result of a school science club group that interested students in contributing to a national survey of earthworm species. John Sabine pioneered the utilization of earthworms as a protein source in animal feed when he was at the Waite Agricultural Institute in Adelaide.

Regional conferences on vermiculture were held earlier this year, supported by the Australian Worm Growers Association and the New Zealand Earthworm Association. Presentations were made by a number of researchers who included: Clive Edwards of Ohio State University on technologies and engineering systems of vermicomposting, as well as the biology of earthworm species; John Buckerfield of OSIRO in Adelaide on his research into soil improvement and crop production; Gerard Gillespie of ACT in Canberra on cost benefits; John Sabine of Vermiculture Resources International on development of earthworm technology; and regional managers of vermicomposting projects.

NEED FOR IMPROVED TECHNOLOGIES AND QUALITY STANDARDS

The technology for processing organic wastes by vermiculture has evolved from ground beds or windrows to produce earthworms as fish bait that developed in the late 1970s and 1980s. Many worm growers are still using such relatively inefficient methods to produce their vermicomposts or vermicasts. However, the development of new vermicomposting technologies has attracted considerable interest from many waste authorities and financial support from local sources as well as the Australian Government. The methodologies described by Clive Edwards ranged from these low technology methods, through improved wedge systems of vermicompost production to high technology systems with completely automated continuous flow reactors, each capable of processing more than 1,000 tons of waste per year. Clearly, the earthworm growers in Australia are producing a wide range of products, varying considerably in characteristics and performance a reflection of the great diversity of organics and mixtures that are being processed and the degree of processing by the earthworm growers.

Many growers have marketing problems for their vermicomposts, usually related to this variability in their products. Although many growers claim to have tested their products for growing plants, often these tests were not conducted on strictly scientific methods with controls and replicates; results were sometimes very difficult to interpret.

It was very clear from the discussions that there is an urgent need for quality standards for vermicomposts similar to those that have been developed in Australia for composts, soil conditioners and mulches (Standards Australia A.54454, 1997). In this document, various characteristics, such as organic matter content, pH, electrical conductivity (salt content), form of nitrogen and phosphorus, carbon:nitrogen ratio, plant toxicity, moisture holding capacity, particle size, density and other standards are summarized together with the appropriate methodologies. The earthworm growers at the Conferences classified their products into three main groups: organic fertilizers, soil conditioners and horticultural plant growth media, and emphasized the need for quality standards to be developed for each of these commercial outlets.

VERMICOMPOSTING ACTIVITIES AT AUSTRALIAN SITES

A diverse range of vermicomposting activities were toured following the conferences. For example, an outstanding project on viticulture, advised by John Buckerfield, was seen near Adelaide at a large and progressive vineyard. The organics from grape processing were vermicomposted with about a 60 day retention time. When the vermicompost produced was added to vines under straw mulches in several experiments, increase in grape yields of between 20 percent and 50 percent were obtained at the first harvest! These investigations will continue, particularly to determine possible effects on grape quality.

On a visit to a piggery near Canberra, a sophisticated system which processed all of the manure from the pigs was seen. The liquid manure was passed into a storage lagoon and then through a specially designed dewatering separator, vermicomposted in windrows, screened to provide a quality product and sterilized, prior to marketing.

In both Australia and New Zealand, a number of composting toilets of various designs using earthworms were seen. All of these seemed to be handling large quantities of human sewage, with virtually no odor problems although how they function and the nature of the compost produced is not completely clear. The most sophisticated of these, the Dowmus Composting Toilet, had fan aeration and a compost extraction auger. Such toilets have been adopted in remote areas of state parks in Australia and New Zealand where there is no running water and appear to have potential for wider adoption.

There seems to be considerable anxiety in Australia about predation on earthworms by terrestrial flatworms (Planaria) which seem to be increasing in numbers to levels which have the potential to affect ground-based vermicomposting systems if they continue to spread.

The greatest impression from the lecture tour was the considerable strength and member enthusiasm of the Australian Worm Growers Association (750 members) and the New Zealand Earthworm Association (250 members).

Clive Edwards is Director of the Sustainable Agriculture Program at The Ohio State University in Columbus. Jean Steele is with the Australian Worm Growers Association in Victoria. Other vermicomposting projects in Australia and New Zealand were described in the June, 1996 issue of BioCycle

JULY 1997 BIOCYCLE pages 63-64