A paper in the May 31, 2002 issue of Science (Mader, et al., 2002)
contains the summary of an
experimental comparison of three systems of agricultural production -
biodynamic, organic and conventional (or integrated) farming - which has
been carried out in Therwil near Basel in Switzerland for the last 24 years.
The DOK (an acronym derived from the German designations
biologisch-dynamisch, organisch-biologisch and konventionell) trial is being
conducted in Switzerland by the Research Institute of Organic Agriculture
(FiBL) in Frick and the Swiss Federal Research Station
for Agroecology and Agriculture (FAL) in
Zürich-Reckenholz
. It will be continued
for at least the next four
years and probably longer still. Nowhere in the world has such a long-term
study been conducted and the experiment yields impressive statistics which
demonstrate that organic agriculture is kinder to the environment, more
efficient and more sustainable. Publication of the findings in
Science (the
first time that the journal has carried a European paper on organic farming
research) signifies a definitive breakthrough for organic farming research.
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. Not all crops did equally well. Potato
yields on organic plots were only 60 per cent of those on conventional
plots. But organic winter wheat achieved 90 per cent, and grasses fed on
manure did just as well as those fed on fertilizer.
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. In 1978 the researchers began studying four plots of land planted with winter wheat, potatoes, beets, grass clover and barley (see image). Farmers cultivated two of these fields conventionally. For the remainder, they utilized organic methods, substituting compost and manure for synthetic fertilizers and using mechanical weeding and plant extracts instead of chemical pesticides. The scientists found that organic soils harbored about 50 percent fewer nutrients (because plants received no artificial fertilizer) but yielded on average only 20 percent less crop. Thus, plants farmed organically used available nutrients more efficiently. How does this happen? It seems that biodiversity on organic land is far higher than in traditionally cultivated soils. Moreover, root-colonizing fungi that help plants absorb nutrients, as well as pest-eating spiders and nutrient-cycling soil microbes, exist in significantly greater numbers on organically tilled plots. "I think our research could stimulate governments to encourage [organic methods] by showing long-term benefits," said Paul Mäder of FiBL. "These results are encouraging for farmers, because they can see that yields are stable over time and that soil fertility has increased. "We have shown that organic farming is efficient, saves energy, maintains biodiversity and keeps soils healthy for future generations."
Reference
Mader, P., A. Fliessbach, D. Dubois, L. Gunst, P. Fried, and U. Niggli, 2002: Soil fertility and biodiversity in organic farming. Science, 296, 1694-1697.