EFFECT OF WEED MANAGEMENT STRATEGIES ON SOME SOIL-ASSOCIATED ARTHROPODS IN MAIZE AND ASPARAGUS ECOSYSTEMS

Five weed management strategies (Sawdust mulching, repeated spring/sum mer cultivation, hand-hoeing and two herbicide treatments) were applie d to each of two cropping systems (maize and asparagus) near Hamilton, New Zealand. Assessments were made of the soil macro-fauna (pitfall t rapping) and mesofauna (modified Tullgren extractor) over a one year p eriod. Many groups of soil macrofauna (most notably two staphylinid be etle species) were much more abundant in the sawdust mulched plots tha n the other treatments, and sporadic relationships between weed biomas s and macrofauna were also detected. Multivariate ordination methods d emonstrated that beetle species assemblages in sawdust mulched plots w ere often distinct from those in the other treatments and such plots t ended to promote higher species diversity; these trends were most appa rent in the asparagus. Of the mesofaunal groups encountered, only Coll embola showed consistent responses to the various treatments considere d, and were sometimes enhanced in the sawdust mulched plots in both cr opping systems. It is concluded that weed management strategies may ex ert significant indirect effects on the soil arthropod fauna, probably by modifying the quality of their habitat.