The latest issue of Science dated 31.5.2002 contains the summary of an experimental comparison of farming systems which has been carried out in Therwil near Basel in Switzerland for the last 24 years. This trial, which compares three systems of agricultural production biodynamic, organic and conventional (or integrated) farming is known as the DOK trial (an acronym derived from the German designations biologisch-dynamisch, organisch-biologisch and konventionell). Nowhere in the world has such a long-term study been conducted. Publication of the findings in this authoritative scientific journal signifies a definitive breakthrough for organic farming research.
This is the first time that the journal Science has carried a European paper on organic farming research. The results of the experiment will have highly significant political, scientific and economic implications for conservation of the agricultural production base and natural biodiversity.
The DOK trial demonstrates that organic crop production is amazingly efficient. Although expenditure on fertilizers and energy was 50% lower and pesticide use was 97% lower, yields of organic crops over a 21-year period were only 20% lower on average.
The DOK trial is also informative on the issue of soil fertility, which is clearly encouraged by organic husbandry. Double the numbers of soil microorganisms, earthworms and ground beetles are found in the study's organic plots. Organic production systems rely in part on organic soil activity to achieve considerable yields using lower inputs of non-renewable resources while maintaining higher soil fertility and better soil structure.
The organic plots not only exhibited higher soil-organism activity, but also a greater diversity of microorganism, weed and ground beetle species. Hence organic farming helps to maintain high levels of biodiversity despite agricultural use of the land. The active, diverse communities of microorganisms ensured efficient use of organic sources of carbon in the soil. It is particularly interesting that the evidence points to a definite correlation between efficient above-ground production (energy input per unit of yield) and efficient production in the soil (soil respiration per unit of microbial biomass). When subjected to intensive interventions via fertilizers and pesticides, the microorganisms evidently become stressed and make heavier demands on resources for their own survival.
- FiBL Contact for technical questions concerning the trial: Paul Mäder
- FiBL Contact general questions on organic agriculture: Helga Willer, Urs Niggli
Mäder P., Fließbach A., Dubois D., Gunst L., Fried P., Niggli U. (2002) Soil Fertility and Biodiversity in Organic Farming. Science 296, 1694-1697
Fulltext in Organic Eprints
Organic farming produces smaller crops, healthier soils, Swiss researchers report in Science
30-5-2002 American Association for the Advancement of Science, Office of Public Programs
Organic farming may produce lower yields, but in the long run it is more efficient and is much easier on the environment, Swiss researchers reported on Thursday
WASHINGTON, May 30 (Reuters)
Organic farming 'a realistic choice'
BBC-News, Science/ Tech, Thursday, 30 May, 2002,
20-year study backs organic farming
30 May 02 NewScientist.com news service
Green fields are efficient Organic farming means quality, not quantity.
Nature, Sciene-update 31 May 2002
Organic Farms Viable Despite Lower Yields, Study Finds
Los Angeles Times,31.5.2002