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Vertisols are characterized by their high clay content, which can hinder assessment of their soil biology. Recovery of nematodes from vertisols with active techniques has indicated that free living nematode numbers within Australian vertisols are often low. Despite this, cotton yield losses due to the reniform nematode have recently been reported in Australia. In light of this and other changes in the cotton production system, we undertook a series of experiments to determine whether passive nematode extraction techniques could be applied to high clay vertisols. Existing published passive nematode recovery methods proved to be inefficient. The use of sodium hexametaphosphate as a clay dispersant was found to further reduce effectiveness. Instead, direct extraction of soil in Ludox at 1.1 g/cm3followed by sieving was found to be as effective at recovering nematodes using Baermann funnel extraction from fresh soil but considerably quicker and three times more effective with dried soil. [ABSTRACT FROM PUBLISHER]

There is a current need to identify European biological indicators of biodiversity and ecosystem function that can be used for soil monitoring, in order to aid policy making. Europe, however, is subdivided into different bio-geographical (climate) zones, containing different soils and varying management practices. This work (as part of the EcoFINDERS project) set out to determine the range of variation in nematode community structure as a potential indicator across European bio-geographical zones, taking into account land use and soil characteristics. Nematodes have been suggested as biological indicators for the monitoring of soil quality due to their involvement in the delivery of functions such as carbon sequestration and recycling of nutrients as well as the provision of habitat for biodiversity. Using a molecular (directed-T-RFLP) approach for rapid nematode community structure assessment and a traditional morphological assessment at a feeding group level, we determined that nematode communities differ between bio-geographical zones and between different land uses within bio-geographical zones. Therefore, at the very large or trans-national level, the presence of any differing bio-geographical zones within the monitored area should be taken into account when sampling and analysing data. Care should be taken when making comparisons across different bio-geographical zones. [ABSTRACT FROM AUTHOR]