Effects of bio-dynamic, organic and conventional farming on ground beetles (Col. Carabidae) and other epigaeic arthropods in winter wheat

Lukas Pfiffner and Urs Niggli

Sponsor(s)/Partners:

Financial support provided by the Swiss Federal Office for Agriculture and the Swiss Foundation of Organic Agriculture.

Purpose

To investigate the effects on arthropods, in terms of species diversity and density, of bio-dynamic, organic and conventioanl cultivation over a long time interval.

Methods

The design consisted of a randomized block trial with four replicates of each treatment having the same crop rotations, cultivars, machinery and cultivation techniques. Differneces in plot treatments were with respect to plant protection and fertilization. Pitfall traps, four per treatment and several at the margins, caught epigaeic arthropods during 20 capturing periods from 1998, 1990-91 each lasting 4-5 days.

Results

Throughout the trial nearly 2 times as many carabids, staphylinids and spiders were found in biological (organic and bio-dynamic) than conventional sites. Significant differences were noted in 2 years for carabids and staphylinids and one year for spiders. On average, the bio-dynamic plots had 7.5 times, and organic plots 4 times, more species than the conventional plots. The assertion that fertilization and plant protection methods, or consequences of, are the explanatory factors for the differences is discussed. The number of carabid species in biological plots was greater and the distribution more even, including the presence of some endangered species.