SKILLEBY LONG TERM FIELD TRIAL 1991-2010
Artur Granstedt, Lars Kjellenberg
Background
At the Biodynamic Research Institute in Järna, Sweden three sets of long-term field trials
have been conducted since 1958. The basic aim was to develop biodynamic farming during
Nordic conditions. The experiments started as an initiative within the Nordic Research circle
for biodynamic agriculture, founded 1949 with members from the all Nordic Countries.
K-trial in Järna 1958 -1990
This trial period lasted for 32 years from 1958 to 1990. The main research question concerned
the quality of agricultural food products under different farming and especially fertilizing
conditions. Also the interaction and influence on soil fertility of different manuring techniques
were studied 1-4. The difference between a cultivation that uses organic fertilizer compared to
one that uses mineral fertilizer and where both achieves comparable yield-levels can
according to the results from the K-trial be summarized as:
Soil
- higher enzyme-activity, soil respiration and occurrence of earthworms
- more deep going soil processes
- considerably higher nitrogen-mineralising capability
- better soil-fertility
Crop
- better storage efficiency and resistance against decomposition
- higher grade of maturity
- higher amount of leguminous plants in the clover/grass ley
The fully biodynamic treatment was characterised by a considerable higher amount of carbon
in the soil, especially below plough depth. The biodynamic treatment also decreased the
sensibility of the plant against potato blight. The biodynamic preparation tended to increase
the yield during years when the common yield level was low and to decrease yields when the
common yield level was high.
UJ –trial 1971 -1979
The results from the initial K-experiment formed the basis for one 6 and one 9-year trial,
which were carried out by the Biodynamic Research Institute in collaboration with SLU
(Swedish University of Agricultural Sciences) on two locations, in Ultuna near Uppsala and
in Järna. The field trials had the same layout on both locations; four replications and all three
crops in the three year crop rotation each year. In the trials Biodynamic cultivation with and
without leys was compared with conventional cultivation with and without leys in three-year
crop rotations. These trials resulted in the first doctoral dissertation within biodynamic
cultivation in Sweden 5 and a report from the 9-year trial in Järna 6. Results from the two trials
corresponded well with each other as well from the K experiment 7. This means that the
biodynamic treatment in comparison with the conventional had:
10 % less yield (summer wheat)
Less storage losses (potato)
Higher dry matter content (potato)
Superior protein quality (potato)
Higher content of vitamin C (potato)
Better cooking quality and taste (potato)
Skilleby long term trial 1991-2011
When the K-experiment ended in 1990 field studies were established within Skilleby research
farm. This made it possible to evaluate the consequences of different treatments within a
given farm situation. The aim was to study how the farm’s own manure could best be treated
and used to promote soil fertility characteristics, the economic use of nutrients, the level of
output (yield) and the nutrient quality of the products, while minimising negative impacts to
the environment, all in the context of biodynamic agriculture