Promoting soil functioning by maintaining soil microbial diversity and activity is central to sustainable agriculture. In viticulture, soil management often includes tillage, which poses a multifaceted disturbance to the soil environment and directly and indirectly affects soil microbial diversity and functioning. However, the challenge of disentangling the effects of different soil management practices on soil microbial diversity and functioning has rarely been addressed.
Aim and layout of the experiment
In this study, researchers investigated the effects of soil management on soil bacterial and fungal diversity as well as soil functions (soil respiration and decomposition) using a balanced experimental design with four soil management types in nine vineyards in Germany for two consecutive years. The application of structural equation modelling enabled them to investigate the causal relationships of soil disturbance, vegetation cover, and plant richness on soil properties, microbial diversity, and soil functions.
Results and discussion
Although patterns found in one year were less pronounced or insignificant in the other year, researchers showed that soil disturbance represented as the frequency of tillage events directly affected bacterial and fungal diversity. While fungi were negatively affected by disturbance, probably due to mechanical disruption of hyphal networks, bacterial diversity was enhanced by disturbance. For viticulture, this highlights the necessity to take into account that soil management options could favour specific groups of organisms while others are impaired.
Additionally, researchers could show that soil bacterial diversity is promoted by above-ground plant richness in vineyards. Soil management that includes sowing of species-rich seed mixtures might, therefore, be beneficial not only for the diversity of pollinators and other insects but also for belowground microbial diversity.
Soil respiration showed a positive response to soil disturbance, while decomposition was negatively affected in highly disturbed soils via mediated effects of vegetation removal.
Occasional disturbance while maintaining a sufficient vegetation cover and a high plant diversity by application of seed mixtures could be beneficial for soil microbial diversity and for supporting ecosystem functions in vineyards. However, variation of results between years requires multi-year, continuous sampling in order to derive recommendations for winegrowers.
The results contribute to the understanding of the direct and indirect effects of vineyard soil management on soil life and aid in designing targeted recommendations for agricultural soil management in the future.
Pingel, M., Reineke, A., & Leyer, I. (2023). Disentangling the mixed effects of soil management on microbial diversity and soil functions: A case study in vineyards. Scientific Reports, 13(1), 1-14. https://doi.org/10.1038/s41598-023-30338-z
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