Agroecology and ecological efficiency
Agroecology and ecological efficiency
Without the profound knowledge of energy studies of ecological systems it is not possible to address the complex field of agroecology.
The organization of ecosystems responds to both a criterion of efficiency in the transformation of energy and its accumulation in more stable forms.
Ecosystems are real accumulators of energy in biochemical form. The greater complexity of the same increases at the same time both the efficiency of the transformation and the ability of the individual organisms to exchange energy quotas in forms with a lower entropic level. Ultimately, in the presence of greater biodiversity, the rate of energy transformation at its own expense decreases and with it, consequently, also the entropy produced.
This expedient of Nature “resolves”, in its entirety, the impossibility of individual living beings to “feed” on an unstable form of energy but to do so through the various forms elaborated in the trophic chain.
To understand this function, the concept of primary productivity of an ecosystem was introduced, i.e. its ability to operate this fundamental chain of transformations.
The concept of primary productivity thus becomes the reference parameter around which to understand not only the status of an ecosystem but also the characteristics that artificial ecosystems must have, i.e. those built by man, including agroforestry systems.
In this sense, the parameter being evaluated is no longer the production yield of a single crop but of the entire system (biomass, fertility, soil, water, air, etc.). In fact, in a specialized system we can have, as often happens in monocultures, high production yields of a species but low transformation capacities of the energies supplied and therefore, ultimately, low process yields.
Agroecology therefore does not change the principles of agronomy but places them in relation to energy issues and their balance and evaluation. In this way, agronomic choices must be placed on the level of stability of ecosystems, with a view to their capacity for regeneration in the long term.
In this direction, the evaluation of Biodiversity Indicators for sustainability in agriculture also becomes fundamental, i.e. those parameters for understanding and evaluating the quality of agroecosystems (Caporali F. et al. 2008).
Biodiversity indicators are used to evaluate and monitor the biological diversity of an ecosystem, a region or, ultimately, the entire planet. They help provide quantitative information on the abundance, distribution and variety of species, as well as the structure and functioning of ecosystems. Indicators are therefore useful tools for measuring changes in biodiversity over time.
Going into the specifics of agricultural systems, these indicators help us to better understand their redevelopment and their ability to optimally fulfill the energy role that falls to them and the relationships with the entire natural and social ecosystem.
Biodiversity indicators in agriculture represent essential tools useful for measuring and evaluating the level of biodiversity present in a specific agricultural environment. These indicators are essential for monitoring the impacts of agricultural practices on the ecosystem, identifying potential problems and developing strategies to promote biodiversity. Some examples of biodiversity indicators in agriculture include:
– crop diversity; measures the number of different species grown in an agricultural area. Greater crop diversity can help protect against disease, improve yields and increase agriculture’s resilience to environmental variations;
– crop rotation; evaluates the frequency with which crops are changed on a given area over the years. A well-structured crop rotation helps maintain soil fertility, reduces the incidence of parasites and diseases and promotes biological diversity;
– soil indicators; they measure soil health and biodiversity, such as the number of soil organisms, the presence of microorganisms and soil structure. Healthy soil supports greater biodiversity of plants and animals;
– insect biodiversity; evaluates the diversity and abundance of beneficial insects, such as bees, butterflies and predators, which play a crucial role in crop polinisation and pest control;
– biodiversity of birds and wild animals; monitors the presence and variety of bird and wild animal species in agricultural areas. These animals can be important allies in agroecology, contributing to the control of parasite populations and the promotion and protection of plant diversity;
– use of pesticides; measures the use of pesticides in the agricultural environment. Excessive use of pesticides has a negative impact on biodiversity, harming beneficial insects, birds and other organisms;
– natural habitats and ecological infrastructures; evaluate the presence of natural habitats, such as woods, hedges, ponds and wetlands, in or around agricultural areas. These ecological infrastructures can serve as corridors and refuges for wild animals and promote biodiversity;
– water and energy consumption; monitors the consumption of natural resources such as water and energy in agriculture. Efficient use of these resources can help preserve and promote natural habitat and biodiversity.
The combined use of different indicators can provide a more complete view of an agricultural system and help develop more sustainable and environmentally friendly practices, implementing much more efficient useful energy dissipation systems while decreasing feedback or feedback from the system itself.
This conceptual revision, as we will see later, completely changes the solutions to be adopted to bring to fruition, and therefore to long-term stability, agricultural, livestock or forestry production.
In this sense, the research of the Russian chemist Ilya Prigogine, Nobel Prize winner for chemistry in 1977, on dissipative systems (which ecological systems are) was fundamental.
In 1979 Prigogine published the book: La Nouvelle Alliance, together with Isabelle Stengers, a Belgian chemist specialized in Philosophy of Science. Metamorphoses of science; the starting point of their arguments are dissipative structures. Subsequently, still on this topic, in 1982, together with Grégoire Nicolis, a physicist of Greek origin, he published the book: Dissipative structures – Self-organization of non-equilibrium thermodynamic systems.
Beyond the notable philosophical repercussions on the understanding of the world, the merit, especially of Prigogine, was to bring the attention of scientists towards the link between order and dissipation of energy, moving away from the generally static and equilibrium situations studied until then and from which the static vision of ecological systems and intensive agricultural production systems was also born.
Prigogine, with his method of analysis, contributed significantly to the birth of what is now called the epistemology of complexity. The Russian scientist made us understand how in nature isolated systems are only an abstraction or particular cases, while the rule is that of open systems (such as ecosystems) which exchange energy with neighboring systems, allowing them constant and dynamic evolution and coevolution.
In this way Prigogine and other scientists review the limits posed by Newtonian physics, still strongly rooted in the 20th century, helping to build the foundations for understanding the energy dynamics of ecosystems, which are, to all intents and purposes, the dissipative structures par excellence present in nature.
A dissipative structure is in fact defined as a thermodynamically open system that works in a state far from equilibrium and capable of exchanging energy and matter with the surrounding environment. In this way, dissipative systems are characterized by the spontaneous formation of anisotropy, that is, of ordered and complex, sometimes chaotic, structures; such systems, when crossed by increasing flows of energy and matter, can also evolve: this evolution occurs through various steps and some of these steps are characterized by phases of instability; two events result: an increase in order, or rather in the complexity of the structures, and a decrease in entropy: in this case we also speak of local negentropy, a principle which, only apparently, goes against the laws of thermodynamics, according to which disorder or rather, entropy always increases.
Examples of dissipative structures include cyclones, the Belousov-Zhabotinskyi chemical reaction, lasers and, on a larger and more complex scale, ecosystems and life forms.
With his epistemological change of direction, Prigogine and other scholars (including Francisco Varela, Harold Morowitz and Enzo Tiezzi, to name a few) began to build a bridge between physics, chemistry, ecology and the social sciences, to study these sectors not separately, but as interacting systems.
This conceptual evolution leads to a new scientific logic that contrasts with the classic idea that nature always follows the simplest path. In this sense, the functioning of the “nature machine” is due to the complexity of irreversible processes; thus the study of entropy provides a measure of the disorder of a physical system or more generally of the universe: based on the laws of thermodynamics it can be said that when a system passes from an ordered state to a disordered state its entropy increases ; however, in the history of the universe there is an exceptional, extraordinary event, which denies and opposes the principle that entropy always increases: this event is at the basis of the principles that characterize the emergence of life on Earth and its evolution, with the various forms and diversities that tend to organize themselves into more stable forms.
Spontaneous organization goes against the presumed balance of the natural order and therefore against the idea of the simplicity of phenomena; complexity becomes the absence of energetic balance and physical disorder; in this way the physics of non-equilibrium was developed, characterized by the main role of non-equilibrium, by the absence of linearity of events. Far from equilibrium, coherent states and complex structures are created that cannot exist in a world of reversibility: in short, nature creates dissipative systems through the diversity of living beings and their bonds and organizations.
Nature, through diversity and mutuality, thus tends to generate more stable forms of life.
The consequences of such an assumption are, obviously, notable: life is no longer an occasional and unlikely phenomenon, but a property of the universe, destined to come true when the right conditions are created.
At the center of this criterion are no longer the individual elements or organisms but their complex and their interactions. Criterion that fits perfectly with the formulation of the Gaia hypothesis, according to which living organisms on Earth interact with the surrounding inorganic components to form a complex synergistic and self-regulating system that helps maintain and perpetuate the conditions for life on the planet (Lovelock J. 1979).
Agroecology therefore becomes the science that incorporates these concepts, entering decisively into this new vision which, unfortunately, in the reductionist culture that generated modern agriculture, limited itself to studying the effects and relationships between a few elements, without worrying about the interactions much more complex ones involving ecosystems and, at most, the ecosystem of ecosystems that is planet Earth.
Thus we can no longer talk about the productive yield of a single agricultural species, taking into consideration its local absolute value (yield per hectare) without observing all the relationships between this yield and the more complex links that this entails (supply of nutritional elements , decrease in biodiversity, interference with soil fertility, social reorganisations, etc.).
From what has been expressed so far, it is clear that the principles on which agroecology is based become more complex in nature but, essentially, they tend to apply production models that respect the basic elements of the energetics of ecological systems. In this way we guarantee not only the long-term stability of these but, at the same time, greater efficiency of the same and, consequently, contrary to what is thought, greater primary productivity and, therefore, as now proven by numerous meta -analysis, a greater offer of products and services, which translated into business terms, equates to better income for farmers.
Guido Bissanti
This article is one of the summaries emerging from the forthcoming book on agroecology (spring 2024) signed by the undersigned and the other researchers: Giovanni Dara Guccione (CREA-PB), Barbara Manachini (UNIPA), Paola Quatrini (UNIPA) and with the preface by Luca Mercalli (president of the Italian Meteorological Society).