organic farming
A number of field experimental units were established in 1996 under DARCOF for use in organic farming research in Denmark. These organic experimental units have been valuable assets for organic farming research in Denmark. They have ensured that research activities were conducted on fields with good organic farm management and with a docu- mented history of the sites. Good experimental units should not only be managed organically, but also reflect the variation, farming practices, soils and climate.
The experimental units cover all major organic farming practices and soil types in Denmark.
These units primarily consist of field experimental sites at Flakkebjerg, Foulum, Jyndevad, Årslev, Askov and KVL- Taastrup, and the long-term crop rotation experiments at Jyndevad, Foulum, Flakkebjerg and Holeby. The organic farming research station, Rugballegård, is also part of the set of facilities.
Some of the experimental units have been designed as separate experiments, where the long-term effects of crop rotations, cover crops and animal manure are investigated. These experiments also function as experimental units, where specific experimental and project activities focusing on interactions with soil fertility, cropping practice and cropping history are performed. Examples of this are the possibilities of exploiting residual nitrogen effects, the risk of detrimental soil compaction, the interaction of genetics and environment in relation to crop and cultivar choice, problems with establishment of cover crops, and occurrence of weeds and diseases.
The aims of the experimental units for research in organic farming systems are three-fold:
1. To describe long-term effects of organic farming practices and crop rotations
. To function as workshop facilities for other, more specific research projects
IV E xp er imen tal units fo r re se ar ch in o rganic farming sys tems (EXU N IT) IV .2 Co mmunica tio n with basis in exp er imen tal units fo r o rganic farming (EXU N IT-2)
3. To assist in communication and dissemination of the results of research in organic farming
Experiences from the experimental units
The research station for organic farming, Rugballegård
The research station for organic farming at Rugballegård comprises activities on both crops and livestock production and therefore offers possibilities for studying interactions between plant- and animal production. Three different sy- stems are represented: cattle, pigs and mixed cattle and pigs. The experiences show that the mixed system offers possibi- lities for increasing crop productivity despite a slightly lower
amount of animal manure, which indicates a higher nutrient use efficiency in the mixed system.
Workshop areas at Jyndevad, Foulum, Årslev, Flakkebjerg and KVL-Tåstrup
These workshop areas have been designed with different crop rotations (for cattle, arable crops, vegetables or fruits and berries). The experience shows that there are few agro- nomic problems in the crop rotations for cattle and dairy farming, whereas there are larger challenges with respect to nutrient supply and weed control in arable crop rotations. However, the six-course rotation for the vegetable crop production at Årslev has demonstrated that proper rotations with cereals, grass-clover and catch crops makes it possible
Table 1. Dairy farm crop rotation in the nutrient cycling experiment at Foulum, from 2003
Field Crop Manure treatments (kg N/ha)
1 Spring barley, under-sown 1. Slurry, 60 N
grass-clover
2 1st year grass-clover 2. Slurry, 120 N
3 2nd year grass-clover 3. None3
4 Spring barley1 + catch crop 4. Deep litter, 120 N
5 Spring oats + catch crop
6 Silage maize2 + catch crop
Previously: 1 barley/pea whole-crop silage, 2 fodder beets without catch crop, 3 360
kg N/ha in deep litter
to maintain good production of vegetables, even without the use of animal manures.
Several of the workshop areas were converted to arable crop rotation in 003 to make it possible to increase research on the agronomic problems in these rotations.
Results from long-term experiments
Grazing intensity and residual effects of pastures Results from experiments with grazing intensity and resi- dual effects of pastures have shown that the huge N-pool in grazed grassland mineralised upon cultivation presents a
potential environmental hazard. Using good management practices (spring ploughing and catch crops), the release of N from three-year-old grasslands gave a considerable resi- dual effect for two years after ploughing with relatively little nitrate leaching. A further improvement of N use efficiency requires more consideration of management during grazing.
Experiments on grazed grasslands have shown considerably higher N leaching from pure grass stands than from grass- clover mixtures, which indicate larger buffering capacities of the grass-clover leys. This hypothesis has been confirmed from results of an experiment on nutrient management in crop rotations in organic dairy farming. This experiment involved varying rates and types of animal manure, and
IV E xp er imen tal units fo r re se ar ch in o rganic farming sys tems (EXU N IT) IV .2 Co mmunica tio n with basis in exp er imen tal units fo r o rganic farming (EXU N IT-2)
the results only gave small differences in production and N leaching between treatments, indicating that grass-clover pastures also here played a stabilising role (Table 1).
Demonstration and communication
Field days have been held at all experimental units, and additionally, a number of farmer groups and other guests have visited the workshop units. Results have also been communicated through other meetings and through several media, including magazines, radio, TV and other electronic media (including targeted web sites). Every year, a three-day seminar has been held at one of the experimental units, pri- marily targeted for advisors in organic farming. Participants in this course have expressed their great satisfaction with this arrangement. Many of the demonstrations and commu- nication activities have been organised in collaboration with the DARCOF secretariat. Finally, the experiences from the research activities have been communicated on the website: www.okologgen.dk.
Project leader
Jørgen E. Olesen, research professor Danish Institute of Agricultural Sciences, DK-8830 Tjele
E-mail: [email protected]
Project participants
Margrethe Askegaard, Bent T. Christensen, Hanne Lindhard Pedersen, Frank W. Oudshoorn, Ilse A. Rasmussen, Kristian Thorup-Kristensen, Kristian Kristensen and Jørgen Eriksen, Danish Institute of Agricultural Sciences,
Hanne Lipczak Jacobsen and John R. Porter, The Royal Veterinary and Agricultural University, Michael Tersbøl, Danish Agricultural Advisory Service
Publications and further information
See the project website:
www.darcof.dk/research/darcofii/iv1.html and the internet-archive: www.orgprints.org
Seed-borne diseases can cause serious problems in the production of cereals and legumes. In conventional agriculture, these diseases are intensively controlled by seed treatment, but this is not an option in organic agriculture.
The threshold levels used today are developed under the presumption that pesticides can be used in case of later disease development in the crop, but no experiments have been made to confirm if the same threshold levels apply under organic farming practice. The project has investigated these thresholds in field trials for diseases in peas and small grain cereals and evaluated them for use under organic farming conditions.