PERFORMANCE OF SPRING BARLEY VARIETIES IN AN ORGANIC CROP ROTATION - EFFECTS OF POSITION IN THE CROP ROTATION AND MANURE APPLICATION

Summary

Organic cropping of spring barley, which is the most common cereal type in Danish organic crop production, requires extensive knowledge about crop responses to different growing conditions due to the limitations in nutrient import and exclusion of pesticides. An experiment was carried out in 2003 and 2004 in a long-term six-field mixed organic crop rotation (barley, 1st and 2nd year grass-clover, barley/(pea/barley), cereal, maize/(fodder beet)). From 1994 each field was divided into four manure treatments with four replicates. We investigated the effects of i) the position in the crop rotation (1st year and 4th year after grass-clover), ii) manure type/amount (slurry and FYM; 0 to 120 total-N ha-1) and iii) variety (six genotypes with different characteristics and two mixtures) on the spring barley performance. There were significant effects of all the tested factors. However, the effects varied with the year and the spring barley performance appeared to be very sensitive to external growth factors like climate and leaf diseases.