Summary

Sweden, began an agricultural field experiment that lasted until 1990, i.e. 32 years. The field experiment included eight different fertilizer treatments, each with a four-year crop rotation without repetitions: summer wheat, clover/grass mix, potatoes, beets. The focus was primarily on aspects of crop quality, and the fertilizer application rates for the various treatments were adjusted to bring about comparable yields. Two "daughter experiments " emerged from the K-experiment and were run in parallel with the mother project during 1971-1976 in Uppsala and 1971-1979 in Järna. In these experiments a comparison was made between two systems, biodynamic farming and conventional farming, in which both fertilizer regimes and crop rotations were studied. One of the main objectives in the K-experiment, i.e. to obtain nearly the same yield over the experimental period in the organic-treatment variants and in the inorganic treatments has largely been achieved, but there were differences between crops. During the time between 1958 and 1990 the yield increased in all treatments in accordance with the overall trend in the Swedish agriculture, but the increase was highest in the organic treatments (65 % in the biodynamic in comparison with 50 % in the conventional). The effects o