What organic farming can do for the environment and society was the focus of a study by the Thünen Institute. The result is a predominantly positive picture of the potential of organic farming.
Organic farming enjoys a good reputation as a sustainable land use system. In order to evaluate its social and environmental performance in a differentiated way, the Thünen Institute, in cooperation with other institutions – including some universities as well as the Bavarian State Institute for Agriculture (Bayerische Landesanstalt für Landwirtschaft) and the Leibniz Centre for Agricultural Research (Leibniz-Zentrum für Agrarlandforschung) – has evaluated scientific literature on this topic.
Twenty-two scientists were involved in the interdisciplinary joint project “Thünen Report 65”, 30 years of research on the ecological project were included. Seven service areas were investigated: Water protection, soil fertility, biological diversity, climate protection and adaptation, resource efficiency and animal welfare. A total of 528 publications from the period from January 1990 to March 2018 were evaluated, in which a total of 33 comparison parameters between organic and conventional farms were considered. This resulted in more than 2,800 individual comparisons.
Water protection and biodiversity
Overall, the evaluation showed that in 58 percent of the comparative pairs analysed, organic farming had advantages over conventional farming in terms of environmental and resource protection. In 28 percent of the cases, however, no differences were found, and in 14 percent the conventional variant proved to be superior.
Organic farming is particularly impressive when it comes to water conservation. Groundwater and surface water is protected in particular by dispensing with chemical synthetic pesticides. In the studies examined, organic farming also reduced nitrogen emissions to water bodies by 28 percent on average. Lower pollution can also be expected for veterinary medicines and phosphorus inputs to water bodies. In this respect, organic farming can be recommended in particular for the management of water protection areas.
The fact that organic farming has a positive and sustainable impact on biodiversity compared to monocultures of conventional farming was clearly demonstrated for the species groups studied. The average number of species of arable flora increased by 95 percent, field birds by 35 percent and flower-visiting insects by 23 percent. However, the landscape structure has a considerable influence on species diversity, especially with regard to fauna, which can greatly overshadow the effects of land use.
Climate benefits controversial
The study results also underline that organic farming can contribute to erosion prevention and flood control. The content of organic carbon in the soil (humus) and aggregate stability were on average 26 percent and 15 percent higher respectively for organic farming; a difference of 137 percent was found for infiltration. This reduces surface runoff and soil erosion. The economical use of resources is also positively reflected in nitrogen and energy efficiency: on average 12 and 19 percent higher respectively.
The contribution of organic farming to climate protection is less clear. On average, organically farmed soils store more carbon and emit fewer greenhouse gases. The scientists determined an average of 1082 kilograms less CO2 equivalents per hectare and year. However, organic farming produces lower yields and therefore requires more land – which offsets the climate benefits. Background: The average yield level in arable farming in Central and Western Europe is between 9 and 40 percent below that of conventional agriculture, depending on location, crop type and farming system.
Challenges in resource policy
There will be no maximum yield with maximum conservation of resources – a classic dilemma. The authors of the meta-study therefore argue that it should always be considered on a case-by-case basis whether resource use or resource protection should be given higher priority. At the same time, they make it clear that even organic farming alone cannot solve the pressing environmental and resource policy challenges without increasing production intensity.
The current yield gap compared to conventional systems should be reduced by breeding more efficient varieties that are specifically adapted to the conditions of organic farming. This also includes varieties more resistant to adverse climatic conditions, pests and diseases. The results of the study were published as the “Thünen Report 65”, which is available as a PDF file at www.thuenen.de.