THE PERFORMANCE OF ECOLOGICAL, INTEGRATED AND CONVENTIONAL NUTRIENT MANAGEMENT-SYSTEMS IN CEREAL CROPPING IN FINLAND

A field trial was conducted during 1989-1992 in order to study the performance of cereal crops under three different nutrient management systems. The systems were divided into conventional, integrated, and ecological groups according to the fertilizer/organic organic manure application ratio and crop rotation. Each group was further divided into the crop-production- and animal-production-oriented rotations, the latter including also leys. Average cereal grain yield of the crop-production-oriented rotation was 5% higher than that in the animal-production-oriented one. However, this difference was not significant. Conventional nutrient management systems produced 6% and 32% more cereal grain than the integrated and ecological nutrient management systems, respectively. Difference to the ecological nutrient management system was significant. The 2-year leys in the integrated nutrient management system produced 8% more dry matter than both the conventionally and the ecologically managed leys. This difference was not significant. Nitrogen yield of the integrated leys exceeded that of the conventional leys by 30% and the ecological leys by 10%. The economic result of the systems indicated greater annual variation in the ecologically managed systems. However, by taking into account 30% surcharge on the ecologically produced products, the greatest gross margin/crop was achieved under ecological nutrient management. Gross margin/crop in the conventional and the integrated nutrient management systems did not differ significantly. A significant part of the mineral fertilizers can be replaced with animal manures, legume undercropping or green fallowing. Grass-legume leys also enabled successful reduction in mineral fertilization.