Response of Soil Aggregate Stability to Manure Amendments in the Ultuna Long-Term Soil Organic Matter Experiment

Soil aggregate stability (SAS) showed a clear response to soil management. SAS increased in following order: bare fallow < no-N < green manure < peat less than or equal to farmyard manure. Humus contents of the plots had a significant impact on SAS. Incfeasing C-org-contents generally enhanced aggregation. However, the unfavourably high C/N ratio of peat treatments and the resulting small size of microbial biomass led to a distinctly lower positive influence of accumulated soil organic matter in case of peat additions.