The conversion of organic wastes into vermicomposts and vermicompost ‘teas’ which promote plant growth and suppress pests and diseases.
Clive A. Edwards*, Norman Q. Arancon*, Tse Chi Kai** and David Ellery**, *Soil Ecology Laboratory, The Ohio State University, Columbus, OH, USA ** Sunburst Waste Management Technologies Ltd, Australia
Most people are familiar with the principles of thermophilic composting, which is a microbial process that utilizes certain aerobic microorganisms to break down organic materials such as wastes. This process involves an aerobic, microbial heating process, which raises the temperature of the organic materials to 55° – 70° C for at least 72 hours, followed by a maturation phase of several days. This process depends on keeping the organic materials aerated, either by turning organic piles mechanically, or by injecting air into enclosed systems. The product has a number of uses as field soil amendments, but has a relatively poor structure and comparatively limited amounts of plant-available nutrients. (Edwards and Bohlen, 1996; Edwards
and Arancon, 2004). More recently, there has been considerable world-wide interest and significant technological progress, particularly at The Ohio State University, on the production and optimal uses of vermicomposts. Vermicomposts can be processed from most organic wastes such as animal manures, and particularly, paper and food wastes, through interactions between earthworms and microorganisms, in a mesophilic process (up to 35°C), to produce fully-stabilized materials with low carbon to nitrogen ratios. They have high and diverse enzymatic and microbial activities and contents, a fine particulate structure, good moisture-holding capacity and contain nutrients such as nitrogen, potassium, and calcium in forms readily taken up by plants. Vermicomposts can have dramatic effects upon the germination, growth, flowering, fruiting and yields of most crops, particularly fruit and vegetables, which are high value crops.