Long-term impact of tillage on microbial communities of an Eastern European Chernozem

Authors: DOMNARIU, HORIA - University Of Bucharest; Trippe, Kristin; PARTAL, ELENA - National Agricultural Research And Development Institute Of Fundulea; BOTEZ, FLORINA - University Of Bucharest; POSTOLACHE, CARMEN - University Of Bucharest

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/24/2024
Publication Date: 1/3/2025
Citation: Domnariu, H., Trippe, K.M., Partal, E., Botez, F., Postolache, C. 2025. Long-term impact of tillage on microbial communities of an Eastern European Chernozem. Scientific Reports. 15. Article 642. https://doi.org/10.1038/s41598-024-84590-y.
DOI: https://doi.org/10.1038/s41598-024-84590-y

Interpretive Summary: Farming practices that disturb deeper areas of the soil, like a moldboard plow (MP), release carbon that would otherwise be sequestered. To avoid carbon depletion, farming practices that either lightly till (disking, DT) or that avoid tillage all together (no till, NT) are becoming more widely adopted. While the influence of these practices has been extensively studied in some cropping systems, very little is known about the use of NT or DT in Chernozem soils. To bridge this knowledge gap, we collected and analyzed Eastern Europe steppe soils used to cultivate corn under these three tillage regimes (MP, NT, and DP). Our study found that reduced and no till practices considerably increased soil carbon and increased the microbial biomass. No till practices increased bacterial, but not fungal diversity. No differences in bacterial or fungal diversity were observed between DT and MP. However, tillage intensity induced changes in the composition of both the bacterial and fungal communities. As such, the communities in soils under NT, DT, and MP were each distinct. These differences have the potential to shape soil functions, especially those involved in the biogeochemical cycling of nitrogen. Overall, our findings illustrate that tillage intensity changes the structure of both bacterial and fungal communities, including distribution of various functional groups, without necessarily improving overall microbial diversity.

Technical Abstract: Conservation tillage is one of the main pillars of sustainable agriculture. As reduced tillage practices continue to spread, there is an outstanding need to improve knowledge of how these practices impact soil microbial communities. Long-term effects of no till (NT) and disk till (DT) relative to conventional moldboard plow (MP) were investigated in a 44-years old experiment run on an Eastern European Chernozem soil under maize crops. We collected samples in spring 2021, before crop sowing. Alongside main soil chemical properties, we investigated microbial communities through amplicon sequencing of the 16S and LSU rRNA genes for prokaryotes and fungi, respectively. Results showed that adopting conservative tillage practices, especially NT, considerably increased soil carbon, active carbon and microbial biomass carbon. The effect of various tillage intensities on microbial biodiversity was higher for prokaryotes than for fungi. In soils under NT, we observed increased prokaryotic richness at both the highest and the lowest taxonomy level, while for both microbial groups it tended to decrease the Shannon index and evenness at the highest taxonomy level. No differences were observed between DT and MP. Conversely, tillage intensity induced a clear separation of both prokaryotic and fungal communities among all three tillage practices. Comparing abundance of ecologically meaningful microbial groups revealed more abundant saprotrophic fungi in MP and also several differences in the bacterial groups involved in the N cycle. At the same time, differential analysis at the genus level showed relatively similar number of prokaryote taxa that may exhibit plant growth promoting features. However, it also revealed higher number of potentially pathogenic fungal taxa that are enriched in NT, a potential risk of this practice. Overall, our findings illustrate that tillage intensity changes the structure of both prokaryotic and fungal communities, including distribution of various functional groups, without necessarily improving overall microbial diversity.