Microbial diversity in archived agricultural soils; the past as a guide to the future

Bacterial diversity and bacterially mediated processes are considered key to soil ecosystem functioning through decomposition and mineralization. However, there is a lack of understanding as to how activity and diversity of prokaryotic communities respond to changes in the environment. At present this issue is mostly addressed by real-time monitoring of long term field experiments, which is costly and slow. Using modern molecular methods we re-analyzed soil samples of up to 50 years old that have been stored in the Alterra soil archive TAGA. We showed that it is indeed possible to detect bacterial fingerprints in those samples and that fingerprints from different samples can be distinctly different, for example between fields that have or have not received organic amendments. These results are a promising first step towards unlocking the microbial information present in archived soil samples. This will help to assess the (likelihood of) changes in soil microbial diversity in response to environmental change (climate change) and human interference (fertilization) and to establish a reference condition and situation. This may further enable coupling to more functional assessments of soil functioning in standardized decomposition essays with the stored samples with known differences in diversity.