Individual study: Reduced fertliser and pesticide inputs results in higher arthropod, earthworm and weed diversity in arable fields in Switzerland
Fliessbach A., Mäder P., Dubois D. & Gunst L. (2000) Results from a 21 year old field trial. Organic farming enhances soil fertility and biodiversity. FiBL Dossier report. FiBL Dossier.
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Use organic rather than mineral fertilizers
A replicated, controlled, randomized study between 1978-1998 of arable farming in Switzerland (Fliessbach et al. 2000) investigated the effect of organic and conventional systems (including use of only mineral fertilizers) on arthropod, earthworm (Lumbricidae), weed and microorganism abundance and diversity. Organic systems had greater earthworm diversity (7-8 species vs 6), density (365-450 individuals/m² vs 247) and biomass (242-261 g/m² vs 183) compared to conventional systems. Earthworm density and biomass was lowest in conventional systems with mineral fertilizers (143 individuals/m², 117 g/m²) and unfertilized plots (217 individuals/m², 137 g/m²). Microorganism biomass was higher in organic systems (312-406 mg microbial C/kg) than conventional systems with manure and mineral fertilizer (271-285 mg microbial C/kg), conventional systems with mineral fertilizer only (171-244) and unfertilized plots (177-208). Ground beetle (Carabidae) diversity was higher in organic (35-38 species) than conventional systems (32), as was the density of ground beetles (99-113 vs. 55), rove beetles (Staphylinidae) (37-40 vs 23) and spiders (Araneae) (58-76 vs 33). Organic systems received approximately 50% less fertilizer (farmyard manure only), than conventional systems. The study was a randomized block design with treatments replicated in 3-6 plots in each of four blocks (96 plots of 100 m²).