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DOK trial

Founded by farmers – carried out by researchers

Test area on the field with many units.

The DOK trial has been comparing conventional and organic farming for over four decades. (Photo: FiBL, Thomas Alföldi)

The DOK trial has been comparing conventional and organic farming for over four decades. (Photo: FiBL, Thomas Alföldi)

The DOK trial has been running since 1978 and is the world's most important long-term field trial comparing organic and conventional farming systems.

In the 1970s, organic farmers and researchers took the initiative to compare organic and conventional farming and set up the DOK trial. Since then, the long-term trial has been jointly managed by FiBL and Agroscope, with support from a farmers' advisory group. 

Over the decades, long-term research topics such as yield development, nutrient cycles and soil quality have been pursued. At the beginning of the trial, the aim was to clarify whether organic farming was even possible under natural weed and pest pressure and whether it could produce sufficient yields. Currently, the focus is particularly on biodiversity, climate impact and climate adaptation. 

Due to the differences in soil quality that have developed over the years in the various farming systems, the DOK has established itself as an interface with basic science. The trial is thus being used to investigate the functioning of organically farmed soils using the latest methods.

Trial setup

The DOK trial is located in the Leimental region south-west of Basel (Switzerland), on fertile loess soils in the south-eastern corner of the Rhine Graben. Here, biodynamic (D), organic (O) and conventional (K) farming systems are compared. These systems simulate farms with arable farming and livestock farming with 1.4 livestock units (LU) per hectare. A crop rotation period runs over seven years; the current crop rotation comprises two years of clover grass, maize, soybeans, winter wheat, potatoes and winter wheat. 

The organic systems follow the guidelines of the organic farming associations Demeter and Bio Suisse. Farmyard manure comes from farms that operate according to the respective systems. The Demeter guidelines require the use of special field and compost preparations. The conventional method now corresponds to integrated production with a balanced nutrient approach, additional use of mineral fertilisers as required and plant protection in accordance with economic damage thresholds. Since 1985, there has also been a purely mineral fertilisation system with conventional plant protection (M). 

Publications

There are publications about the DOK trial for a broad audience, such as a fact sheet and a podcast. In addition, over 130 publications have been produced in scientific journals as part of the long-term trial (see below), including a synthesis of the overall results in 2024. There are also numerous doctoral and student theses.

Dossier, fact sheet and more

In 2024, FiBL published the findings from the DOK trial on yield, soil quality, nutrient supply, biodiversity and climate in various formats. These are aimed at interested experts from practice, consulting and science.

  • The 52-page dossier "The DOK Trial: A 45-year comparative study of organic and conventional cropping systems" provides a comprehensive insight into the results.
  • The 8-page fact sheet "Organic farming in comparison: Results from 45 years of the DOK trial" presents and interprets the most important results in an easy-to-understand manner.
  • PowerPoint presentation "The DOK Trial: 42 years of organic and conventional farming in comparison" presents the most important results in a collection of graphics and accompanying text explanations on 36 slides.  
  • The DOK trial was the focus of issue 8/24 of Bioaktuell magazine.
  • In the podcast "The DOK trial – comparing cultivation systems" (in German), Paul Mäder, who led the trial at FiBL for many years, and Jochen Mayer, long-time head of the DOK trial at Agroscope, talk about their experiences in the long-term trial.

Scientific publications

A detailed list of scientific publications (peer reviewed) from the DOK trial is available here (77.1 KB).

Selected publications

This selection of publications on specific topics covers the entire duration of the DOK trial.

  • Systems in comparison
    The study shows that by foregoing maximum yields, the environmental impact of arable farming can be reduced using organic production methods. Soil quality, biodiversity and the climate benefit particularly from organic farming. Organic farming provides a solid foundation for the further development of sustainable production systems.

    Krause, H.-M., Mäder, P., Fliessbach, A., Jarosch, K. A., Oberson, A., & Mayer, J. (2024). Organic cropping systems balance environmental impacts and agricultural production. Scientific Reports 14, 25537. doi.org/10.1038/s41598-024-76776-1

  • Yield development
    Yields for the main crops clover grass, winter wheat, potatoes, maize and soybeans were on average 15 percent lower in organic systems compared to conventional systems. However, the yield differences depend on the crop and are higher for non-legumes than for legumes. Across all systems, there is a correlation between the amount of nitrogen applied and the use of synthetic pesticides.

    Knapp, S., Gunst, L., Mäder, P., Ghiasi, S., & Mayer, J. (2023). Organic cropping systems maintain yields but have lower yield levels and yield stability than conventional systems – Results from the DOK trial in Switzerland. Field Crops Research 302, 109072. doi.org/10.1016/j.fcr.2023.109072

  • Nitrogen balances and use efficiency
    Due to lower nitrogen fertilisation, organic systems have higher nitrogen efficiency than the mixed conventional system. The study also shows that focusing on a balanced balance in a purely mineral fertilised system leads to nitrogen losses in the soil. An accumulation of nitrogen in the soil could only be achieved in the biodynamic system with the use of manure compost.

    Oberson, A., Jarosch, K. A., Frossard, E., Hammelehle, A., Fliessbach, A., Mäder, P., Mayer J. (2024): Higher than expected: Nitrogen flows, budgets, and use efficiencies over 35 years of organic and conventional cropping. Agriculture, Ecosystems and Environment 362,108802. doi.org/10.1016/j.agee.2023.108802

  • Soil quality and carbon
    Soil carbon is the most important indicator of soil quality, but changes in soil carbon content due to agricultural practices take time. Only after 22 years of experimentation were significantly higher levels found in organic systems compared to conventional systems. Over six crop rotation periods, the biodynamic system in particular showed increasing carbon levels and the highest biological soil quality.

    Krause, H.-M., Stehle, B., Mayer, J., Mayer, M., Steffens, M., Mäder, P., & Fliessbach, A. (2022). Biological soil quality and soil organic carbon change in biodynamic, organic, and conventional farming systems after 42 years. Agronomy for Sustainable Development 42(6), 117. doi.org/10.1007/s13593-022-00843-y

Projects

With its large database and extensive sample archive, the DOK trial offers an ideal platform for a wide variety of research projects. Numerous projects have been carried out in connection with the DOK trial, and thousands of soil and plant samples have been analysed and evaluated.

Below is a list of projects since 2012.

Ongoing projects

Completed projects

Project partners and funding

Project team (on behalf of FiBL)

Collaboration

  • Agroscope (co-coordination)
  • ETH Zurich
  • University of Zurich
  • University of Basel
  • Farmers' advisory group
  • Further project collaborations

Funding

  • DOK basic management: Federal Office for Agriculture FOAG