THE EARTHWORM INOCULATION UNIT TECHNIQUE - AN INTEGRATED SYSTEM FOR CULTIVATION AND SOIL-INOCULATION OF EARTHWORMS

The introduction of earthworms into degraded or newly restored land is known to promote soil improvement. Obtaining the most appropriate spe cies in the large numbers required can be costly and time consuming us ing traditional techniques. Research and development of a novel approa ch, the Earthworm Inoculation Unit (EIU) technique, may help to overco me this. This technique combines cultivation of selected earthworms in small soil-based units, with an effective method of direct soil intro duction. Successful cultivation of deep burrowing species, e.g. Lumbri cus terrestris L. and Aporrectodea longa (Ude), and shallow working sp ecies, e.g. Allolobophora chlorotica (Savigny), has been achieved by o ptimizing environmental factors. Accelerated rates of reproduction com pared with field data have been recorded. At soil-inoculation, each EI U was found to contain all three earthworm life stages, adults, cocoon s and hatchlings, promoting maximum opportunity for successful colonis ation. Results from field trials suggest, that for A. longa, the EIU t echnique can enhance survivorship in compacted clay soils compared wit h a more conventional inoculation method. Earthworm inoculation, where appropriate, should become an integral component of sustainable land restoration practice. In hostile soils, often associated with reclaime d land, the EIU technique may provide a means of ensuring long term su rvival for earthworm populations. (C) 1997 Elsevier Science Ltd.