Yields from organic farming are more than 20% lower than with conventional methods, but organic farming is twice as environmentally friendly, a Swiss study has found.
A field that is farmed organically has 230% more plant species diversity than a conventionally cultivated field, according to a study published on Thursday by the federal agricultural research institute Agroscope.
For this long-term research, scientists from Agroscope and the University of Zurich looked at the impacts of four different farming systems: conventional farming with and without ploughing; organic farming with ploughing; and organic farming with reduced tillage of the soil.
Researchers found 90% more earthworms in the organic plots and 150% more in the no-till plots. There was less soil erosion in these plots. Ecotoxicity is also 81% lower with methods that do not use pesticides.
“If you look at all the environmental impacts, organic farming is clearly in the lead,” said Marcel van der Heijden, head of the study at Agroscope.
Environmental protection, however, is accompanied by lower yields. On average, yields are 22% lower, and even 34% lower in organic farming with reduced tillage.
In terms of yield, “organic farming still has great potential for improvement”, said Raphaël Wittwer, main author of the study which was published recently in “Science Advances”. This ranges from the selection of resistant varieties to the improvement of biological plant protection and the optimisation of fertilisation.
On the plots, the researchers rotated winter wheat, grain maize, beans and clover. The trial has been running for twelve years and “will continue for at least another six years”, says Agroscope.