SOIL BIOTA AS INDICATORS OF SOIL QUALITY IN ORGANIC AND INTEGRATED MANAGEMENT KIWIFRUIT ORCHARDS IN NEW ZEALAND

The Agricultural Research Group On Sustainability (ARGOS) is studying the differences between matched Organic 'Hayward', Integrated Management (KiwiGreen) 'Hayward' and Integrated Management 'Hort16A' kiwifruit orchards in New Zealand. As part of this study, ARGOS is searching for optimal indicators of soil quality. Suitability criteria include practicality, ubiquitousness and sensitivity to management practices. Soil nematode assemblages are ubiquitous and sensitive to management practices, but the specialist skills required to extract and identify nematodes make them costly and impractical indicators. The bait lamina test as a bioassay of soil biological activity for measuring soil biota is inexpensive, rapid and repeatable, but requires further development as an indicator tool for the monitoring programme. Earthworms fulfilled all the criteria for suitable indicators and are recommended for use as an indicator of soil quality in the ARGOS soil monitoring programme. Higher earthworm populations and percentages of omnivorous nematodes were found in soil from organic orchards, suggesting differences between soil food webs from different kiwifruit orchard management systems.