Blueberries Prefer Acid Soils – but too much Acidity is Detrimental

Although there is enormous microbial diversity in blueberry substrate, there is no strong correlation between diversity and yield, according to a new Agroscope study examining the interaction of soil biology and cropping system.

In recent decades blueberry crops have become increasingly important at both national and international level. In Switzerland, around 700 tonnes of blueberries were produced and marketed in 2024.

For both biological and physicochemical reasons, soil and substrate are decisive factors for blueberry production. Of particular importance are mycorrhizal fungi, which live on the roots and help blueberry plants absorb nutrients that are in short supply, such as nitrogen and phosphorus.

Agroscope conducted a study on nine blueberry plantations to determine the influence of mycorrhizal fungi on plant yield and vegetative growth. The aim was to gain a better understanding of the role of soil microbiology in blueberry cultivation and to develop potential optimisation strategies for sustainable production.

Several thousand species groups of bacteria and fungi

The study revealed an immense variety of bacteria and fungi in the substrates of all plantations. Several thousand microbial species groups were identified, highlighting the biological complexity and the potential of these substrates.

Although the plantations examined clearly differed in terms of the prevalence and composition of microbial diversity, no significant difference in the prevalence of mycorrhizal fungi was found between organic production and integrated production (IP). This suggests that the production system affects these specific microorganisms less than previously assumed.

No significant effect of microbial diversity on yield

In addition, although no significant correlation was found between the microbial diversity of the substrate and agronomic performance, previous studies showed that mycorrhizal fungi and other soil microorganisms may be crucial for plant health and nutrient uptake. This suggests that other factors such as nutrient availability or management practices play a more important role on the plantations studied.

Targeted pH management pays off

Substrate pH also proved to be a key factor in agronomic performance. True, blueberries require an acid environment for optimal growth, but too low a pH can negatively affect growth and yields. The significantly positive correlation between pH and yield underscores how important targeted pH management is for high-yielding, sustainable blueberry production.

The results of this study highlight the importance of holistic substrate management that not only takes into account the microbial population but also focuses on physicochemical parameters such as pH and nutrient supply.