Low-input farming systems and beneficial organisms

Lukas Pfiffner, Henryk Luka

Purpose

To assess whether different low-imput farming systems affect the abundance and diversity of carabids and epigeal spiders in landscape units comprised of arable cropland and semi-natural habitats.

Methods

The three year field survey was conducted on 6 paired farm units in northwestern Switzerland where arable cropland (winter cereals) and semi-natural habitats (hedges, low-input meadows and wildflower strips) were studied. Low-input farms (ICM= no insecticides, fungicides or growth regulators) were compared to organic or bio-dynamic units. Carabids and spiders were collected with 5 funnel pitfall traps per site covering 24 winter cereal crops and 18 semi-natural habitats. Samples were obtained during the high activity period of carabids and spiders and main growing season of the cereals.

Results

36% fewer carabids and 8% fewer spiders overall were found in ICM cereal fields in comparison to organic/bio-dynamic. Carabid species, in terms of type and abundance were greater in organic/bio-dynamic fields, however distinctions between the two agricultural management systems were less pronounced for spiders. The most significant factors affecting the carabid populations were farming method and weed abundance, while for spider populations, weed diversity was the dominant factor.