Measuring soil biodiversity: experiences, impediments and research needs

We summarise methods to assess biomass, activity and diversity of soil organisms and show some results. In contaminated soils community structure had changed but diversity was not always reduced. Biomass and activity were much more reduced than diversity. In agricultural soils organic management resulted in an increased role of soil organisms. Replacement of mineral fertilisers by farmyard manure stimulated the bacterial branch of the soil food web. Reduced availability of mineral nutrients appeared to increase fungi, presumably mycorrhiza. Bacterial DNA profiles did not indicate low genetic diversity in agricultural soils. At extensive and biological grassland farms nitrogen mineralisation was about 50% higher than at intensive farms. Not only microbial biomass and activity but also different groups of soil fauna tended to be higher. Soil biodiversity can not be monitored meaningfully with a few simple tools. Extensive and long-term monitoring is probably the most realistic approach to obtain objective information on differences between, changes within, and human impact on ecosystems. In most countries, microbial biomass, respiration and potential N mineralisation are regarded as part of a minimum data set. Adding the main functional groups of the soil food web brings us closer to biodiversity and gives the potential to relate the structure of the soil community to functions