Soil arthropod responses to controlled traffic in vegetable production

In this study, the effects of a controlled traffic (CT) management system on the soil arthropod assemblage in a Red Ferrosol (krasnozem) soil in north-west Tasmania were examined. Individual soil cores were collected at three depths over two seasons (winter and spring, 17 months apart), and soil fauna extracted using Berlese-Tullgren funnels. All arthropods were identified to the level of order and counted. Data were analysed to assess the effects of a controlled traffic system on the overall abundance and ordinal richness of the arthropod assemblage, as well as abundance and species richness in the collembolan assemblage. Multivariate analysis was used to examine the differences in the ordinal composition of the arthropod assemblage. The data were variable between seasons, with significant increases in arthropod and collembolan abundance (p < 0.01) at all depths being evident under controlled traffic in spring. Arthropod richness was significantly greater in spring (p < 0.1), but a similar effect was not measured for collembolan richness. Overall arthropod abundance was greater under CT in winter (p < 0.1), although by depth, differences between treatments were evident only in the deepest samples for arthropod abundance (p < 0.05) and arthropod and collembolan richness (p < 0.1). While it was not possible to separate the relative impacts of traffic and tillage, it is concluded that the controlled traffic system had positive effects on the abundance and diversity of soil arthropods.