WASHINGTON, DC, June 3, 2002 (ENS) - A 21 year comparison of farming methods has shown that organic farming produces crops that average about 20 percent smaller than crops produced using conventional methods. The study by Swiss scientists also found that organic farmers use land far more efficiently and with less environmental impact than other modern farmers.
Unlike conventional farming, organic farming uses no synthetic fertilizers or pesticides. The organic approach more than made up the difference in crop yields through its ecological benefits, argue the scientists who conducted the study.
"There is a need to evaluate alternative farming systems as a whole system in a scientific way. The most appropriate method to do this is still to conduct long term experiments, which can be analyzed statistically and performed under identical soil and climate conditions," Mäder explained. "Soil fertility and biodiversity develop slowly, and this is why a long term study is essential."
Mäder's team compared plots of cropland grown side by side using different farming methods. The crops used included barley, beets, grass clover, potatoes and winter wheat.
Besides examining conventional farming and organic farming, the authors also studied an organic approach called biodynamic farming, based the environmental and spiritual philosophies of its inventor, Rudolph Steiner. Crop rotation, varieties, and tillage were identical in all the systems studied.
"These results should be encouraging for farmers, because they can see that yields are stable over time, and that soil fertility has increased," Mäder said.
Over the course of the study, organic farmers added 34 percent to 51 percent less nitrogen, phosphorus and other nutrients to the soil than conventional farmers. Even so, crop yields from organic systems were just 20 percent lower than those from the conventional systems, which Mäder said shows that the organic systems use their resources more efficiently.
The organic soils were also more fertile in other key ways, such as hosting a larger and more diverse community of organisms, Mäder and his colleagues report. This was true for soil microbes, which govern the nutrient cycling reactions in soils, and for mycorrhizae, root colonizing fungi that help plants absorb the nutrients.
Insects were almost twice as abundant and more diverse, including pest eating spiders and beetles. Weed plants were more diverse in the organic systems, and included some specialized and endangered species, the researchers found.
"Our results suggest that, by enhancing soil fertility, organic farmers can help increase biodiversity," Mäder said.
The organic soils also decomposed more efficiently, the researchers found. This is an important feature of fertile soil, Mäder explained, because the process releases nutrients and carbon to be used by the plants and microbes.
"The organic systems show efficient resource utilization and enhanced floral and faunal diversity, features typical of mature systems," wrote the researchers. "We conclude that organically manured, legume based crop rotations utilizing organic fertilizers from the farm itself are a realistic alternative to conventional farming systems."
In December 2000, the U.S. Department of Agriculture finalized the United States' first national standards for organic foods, barring not only the use of synthetic pesticides and fertilizers, but also genetically engineered crops, irradiated foods and crops grown with sewage sludge.