Biodynamic farming leads to adaptive fungal communities
Translation into Israeli language, written by Lukas Maschek
Agro-ecosystems are managed by humans but remain subject to ecological processes. The type and intensity of the management measures have an effect on the ecological composition of the agricultural system. Fungal communities play a central role in the sustainability of an agroecological system. In this 2021 study, a team of American and Spanish researchers examined the fungal communities of 350 soil samples from vineyard plots. grown in organic and biodynamic farming methods that use less intensive management measures leading to less dense fungal communities, which can adapt to changing environmental conditions. In contrast, intensive interventions, common in conventional agriculture, have led to more specialized fungal networks, which often function according to the principle of mutual exclusion and are more sensitive to temperature. The researchers, led by Rüdiger Ortiz-Álvarez, hypothesized that the composition of soil fungal communities could provide information on how biotic and abiotic factors influence soil ecological processes. Tillage intensity can lead to different ecological strategies within fungal communities.
The study in brief
The living organisms of an ecosystem interact with each other in a complex manner and thus affect the ecosystem in which they occur. This community of organisms is often described in terms of diversity and abundance, meaning how many different species are present and in what numbers. If we also know which species contradict each other and which only work together, we can derive a network-based description of a community of living organisms. This includes the interdependence of individual species and allows conclusions to be drawn about the underlying mechanisms and processes, and about the resulting functioning of the community within the ecosystem.
Figure 1: Conceptual representation of fungal communities. Combining a basic community description (left) with a description of preferences, interactions, and strategies (metaweb, center) results in the network-based community description, which allows interpretations of how different communities respond to changing conditions in an ecosystem (right).
In the present study, such a network-based approach was used to investigate the effects of conventional, organic, and biodynamic agricultural practices on the fungal soil communities of viticultural areas. Agricultural practices—along with geographic and climatic factors—have been shown to influence the composition and structure of fungal ecosystems.
Biodynamically managed vineyards tended to create more clustered and mixed fungal communities, while the fungal communities in conventionally managed soils tended to be less clustered and the individual species were less correlated (co-exclusion). In addition, in conventional systems, the amount of selective fertilizer, which was sometimes high, led to the specialization of certain fungal species, in contrast to biodynamic systems that favored general and dense communities. It is hypothesized that such generalist fungal communities are generally more adaptable when faced with changes in environmental conditions than highly specialized communities. Samples of organically managed soils tended to show values between those of biodynamic and conventional methods.
Figure 2: The different structures of fungal communities according to agricultural management. In conventionally managed soils, the fungal community tends to specialize, compete and create a niche, making it more vulnerable to changes such as the elimination of certain species due to human intervention or environmental changes (left). In biodynamically managed soils, the fungal community tends to have a more cooperative overall structure, similar to the structure of natural soil fungal communities and may exhibit increased stability to external influences (right). The structure of fungal communities in organically managed soils shows characteristics of communities in conventionally and biodynamically managed soils (middle).
This study did not examine the physicochemical soil properties, which could help better understand the observed differences in fungal community composition between biodynamic and conventional agriculture. The authors argue that more research needs to be done. As an example, they cite long-term studies accompanying the conversion from conventional to biodynamic agriculture. Such studies can help better understand the human impact on the soil ecosystem, optimize management practices, and simplify the monitoring and promotion of soil health.
The functioning of agricultural systems is still not fully understood. This is especially true for their resistance and resilience to environmental change. Human intervention in an ecosystem can affect the structure of fungal communities and give rise to two alternative strategies: in biodynamic management, well-mixed soil habitats can develop where fungal communities work more together and are more resistant to temperature fluctuations. In conventional management, more fragmented habitats develop that can cover more specialized niches, but have a lower response spectrum to temperature fluctuations. Fungal communities in biodynamically managed soils resemble the cooperative structures found in unmanaged natural soils. Both the species of fungi present, and whether and how well they cooperate are important factors in soil health.
The researchers hypothesize that cooperative fungal communities, such as those found in biodynamically managed soils, may be more resilient to increasingly changing environmental conditions due to climate and land use change.
The source of the study
Ortiz-Álvarez, R., Ortega-Arranz, H., Ontiveros, VJ, de Celis, M., Ravarani, C., Acedo, A., Belda, I.
The name of the study
Network Properties of Local Fungal Communities Reveal the Anthropogenic Disturbance Consequences of Farming Practices in Vineyard Soils
mSystems, Vol. 6, no. 3. 6:e00344-21 (2021)
(Open Access): https://doi.org/10.1128/mSystems.00344-21
This summary first appeared on the Department of Biodynamic Agriculture website
and includes a reference to the article