THE STATUS OF SOIL MACROFAUNA AS INDICATORS OF SOIL HEALTH TO MONITORTHE SUSTAINABILITY OF AUSTRALIAN AGRICULTURAL SOILS

Australian farmers are searching for reliable, easily measured indicat ors of soil health to monitor sustainability of their enterprises. Ove r the past 5 years earthworms have been promoted as indicators of soil health by some researchers. Others have been reluctant to accept soil macrofauna in general as soil health indicators. Their reluctance is based on the difficulty of interpreting biological data in relation to soil health as there is no clear understanding of the links between s oil macrofauna and soil health. The problem is further compounded by t he inherent difficulty in studying soil biota, inadequate experimental design, and the lack of long-term commitment to funding such studies. This paper reflects on current research, and maps out conditions and directions for future research if the role of soil macrofauna in soil health is to be better understood. The compilation of adequate baselin e data, the appropriate delineation of experimental plots, attention t o the totality of environmental conditions including land management p ractices, the consideration of impact by macrofauna other than earthwo rms, are some of the directions are outlined. The challenge in the fut ure will be to shift the emphasis of soil macrofauna research towards understanding their function in soil processes essential to ecosystem functioning. Without this sort of experimental evidence scientists can not indicate to the farmer whether the soil resource is declining in q uality, is stable or in a process of renewal based on the presence or absence of certain macrofauna. (C) 1997 Elsevier Science B.V.