Introduction to Synergistic Agriculture
From the beginning of the agriculture, the removal of the vegetation from the soil and its plowing were considered as necessary practices, if not essential.
However, after years of experience and studies, it is possible to say that these practices are one of the main causes of the reduction of fertile soil. Moreover, they creates problems of erosion and pauperization of the nutrients in the soil.
Masanobu Fukuoka, a Japanese microbiologist and farmer, has started from the ’30 to experiment a new kind of agriculture.
His experimentation has a revolutionary meaning, because it not only eliminates the plow, but it even keeps the soil covered with a living permanent mulch during the growth of the plants.
Fukuoka has called this new agriculture Natural, because it’s based on synergic dynamics between its component to keep the soil fertile without the need of chemical or organic fertilizer: since the minerals stay in place, it is not needed to compensate their loss with compost or manure.
It’s a common statement in ordinary agriculture that the plants absorbs fertilizing elements and nutrients from the soil. However, in nature the plants create their own soil. So, how is it possible that what they create in nature, is destroyed in agriculture?
Maybe the problem is the way we manipulate the soil, and not the plants themselves.
A plant is made of water for roughly the 75%. The remaining 25% of dry material is made of organic components for the 20%, synthetized with the help of sunlight, and other gases, while only the 5% of its total weight comes from the soil: in other words, we could say that a plant is made of sunlight and air. Only the 50% of the 5% is nitrogen (2,5% of the total weight).
Nitrogen comes from the atmosphere and it can be obtained in a symbiotic way by cultivating some plants that fix the nitrogen in the soil (thanks to some bacteria that usually lives in the soil) , together with edible plants, so that the soil won’t become poor.
The other 2,5%, made of minerals, is fed naturally by the soil: our planet is a sphere made of minerals, just covered by a relatively thin layer of soil, composed by living animals (visible or not), mushrooms, plants and other residuals. The sun will stop lighting us before than the minerals contained in the soil will end.
Fukuoka demonstrates that agriculture and its scheduling can be practiced respecting the natural dynamics of living organisms that find place in the soil. Natural agriculture is based on the law of synergy, refusing the first rule of common agriculture that states: if a certain amount of elements is found in a crop, then the same amount of elements must be re-introduced in the soil.
This principle doesn’t take in account the ability of the plants to synthetize and convert the elements necessary to their growth. Water and ground plants are at the base of the energetic pyramid, they sustain all the other living organisms, so they are certainly capable of developing the organic substances they need, keeping alive the other living organisms that populates the soil.
Microbial interactions in the soil invests a key role in the biological control of plants pathologies, in the organic matter turn-over and by recycling nutrional elements essential to plants growth.
The plants stimulate the microbial activity in the soil, supplying chemical energy by spreading certain elements and substances through their roots (root exudates): the deep connection between plants and microbs of the soil is evident.
Unfortunately, conventional agricultural methods blocks this connection. As a result, the soil becomes poor, while the plants are more prone to pathologies.
Oxygen Ethylene cycle
Recent researches claim that up to the 25% of the chemical energy of a plant spreads towards the soil from their roots, in the form of exudates containing carbon elements produces in the leaves. This matter comes to the soil as root exudates or as dead vegetable cells.
But what about this carbon loss, from the plant to the soil?
First of all, these compounds are an energy source for all the micro-organisms that lives in the rhizosphere, the soil area near to the roots of the plants.
These micro-organisms develop themselves as fast as the oxygen stored in many micro-sites in the rhizosphere is consumed. When oxygen drops, then the microsites becomes anaerobic. These anaerobic microsites have a central role in assuring health and strength to the plant.
At this point, different biochemical reactions start, giving the production of ethylene inside the anaerobic microsites. Ethylene is a simple gas composite, and it’s able to regulate the activity of the micro-organisms in the rhizosphere, influencing the turn-over of the organic matter, the cycle of nutrient elements and the influence of pathologies that originates from the soil.
Ethylene does not kill the micro-organisms, it just inactivate them, as if they were sleeping.
This is how the Oxygen Ethylene cycle works:
The microorganisms proliferate inside different micro-sites in the rhizosphere because the plant emits root exudates in it. Then, these microsites lose almost all the oxygen present, allowing the production of ethylene: when ethylene rises, the microorganisms proliferation slows down because of the gas.
When this happens, the oxygen consumption is reduced, and thus it remains in the microsites reducing the production of ethylene: the microorganisms wake up, and the cycle starts again and again.
Disturbed and wild soils
In wild soils, such as inside a forest, it is possible to register a continuous presence of ethylene, that means that the cycle is active. On the contrary, we can’t measure ethylene in significant amounts in soils disturbed by conventional agriculture techniques.
When natural ecosystems are disturbed for agricultural uses, there is a substantial drop in the amount of organic matter in the soil, the lack of nutrients in the plants becomes common and the pathologies increase drastically.
Plowing is one of the main causes that inhibits ethylene production in the soil, changing the nitrogen composition in it.
In wild soils, nitrogen is present as ammonium, with traces of nitrates. When the soil is disturbed, the composition of the soil changes, and the nitrates becomes much more common. In fact, plowing stimulates the activity of a specific group of bacteria that converts ammonium into nitrate: plants and microorganisms can use both of them, but ethylene cannot be produced when there is too much nitrate, because it inhibits the creation of the anaerobic microsites.
The Iron role in ethylene production
When all the oxygen is consumed in the microsites, a series of chemical reaction starts. One of these reaction is the iron transformation, from the oxidized or ferric form to the reduced or ferrous one.
Iron is one of the main elements in soil composition, as it represents from 2 to 12% of its weight. In wild soils, all the iron exists as little crystals of iron oxide, immobile in soil.
Without oxygen, these crystals translates into their ferrous form, highly unstable. But how the ferrous iron stimulates the production of ethylene?
Ferrous iron reacts with an ethylene precursor that it’s already in the soil, and get the production of ethylene as a result. This precursor is produced by the plants, but is it present only in old and dead leaves. When these leaves fall on the ground and they start to decompose, the ethylene precursor goes in to the soil, and here it stay until the oxygen in the microsites drops, the iron oxide becomes ferrous iron and it reacts with the precursor, producing ethylene.
It shouldn’t be surprising that ethylene precursor is stored in old or death leaves. After all, in a forest old leaves are the main matter of the soil. It is also common knowledge that in conventional agriculture almost every leaf and every residual death plant have to be removed in several different ways, such as burning the field. In this way, ethylene cannot be produces at all because of the lack of its precursor.
Another problem in disturbed soil is the inadequate amount of nutritional elements, as it is the main reason why conventional agriculture uses chemical or organic fertilizers. This shortage in nutritional elements occurs event if they are present in soil, but in a highly insoluble form.
The anaerobic microsites in the rhizosphere that, as we’ve seen, are essential for ethylene production, can play a very importart role in the mobilization of these nutritional elements by converting them in a soluble form.
This dynamic is strictly linked to the role of iron in soil. In wild soils, the iron is present as little crystals of oxide with a wide surface. These crystals are electrically charged. Nutritional elements such as phosphates, sulphates and other micro-elements are joined to this surface. In this form, they are not available for the plants.
However, when anaerobic microsites develop thanks to the oxygen drop in the soil, the oxide turns into ferrous iron, setting free the micro-elements on its surface, so that they can be used by the plant. But this is not the only process in which iron is involved.
Other fundamental nutrients for the plants, such as calcium, potash, magnesium and ammonius, join themselves to clay particles or other organic matter. Ferrous iron is capable to set them free, by joining itself to the organic matter in place of the nutrients, that now can feed the plants.
It is interesting to point out that nutritional elements becomes available to the plants inside the anaerobic microsites, just near the rhizosphere, exactly where they’re needed.
Another aspect of this mechanism is that it naturally prevents soil pauperization: even if the mobilized nutrients are not used by the plants, they cannot be flushed away, because the iron turns again into oxide as fast as it moves at the end of the microsites, creating again the oxide crystals. In this way, basic nutrients joins again with it, and they’ll become available again at the next cycle.
Please note that the necessary condition for this process to work, are exactly the same needed for ethylene production.
In disturbed soils, where ethylene production is inhibited by plowing, event this mechanism is blocked, and the nutrients won’t turn in to their mobilized form.
A correct management of the soil needs a huge move from conventional agricultural practices, such as tillage, that are supposed to aerate the soil. In fact, tillage produces a sudden increase of plants growth in short terms, but considering its consequences in long terms we’ll fine that plowing generates problems of soil pauperization.
New agricultural methods that avoid from plowing the soil can assure a continuous growth of the plants, while keeping the soil fertile. The point is to cover with mulch the soil, increasing the amount of organic matter that returns to it. Is is good to use mature plants as mulch, leaving them just upon the ground, without burying them.
It is difficult to understand these dynamics for the Cartesian science, because of their holistic complexity, but this cultural limit shouldn’t prevent society to find sustainable ways for food production, without destroying the soil.
Synergistic agriculture tries to creates the conditions needed to keep the soil alive and in good health, maintaining its fertility. The aim is to emulate the dynamics of soil self-fertilization that usually occur in nature: this is the main difference between synergistic agriculture and conventional/traditional agriculture, that translates into a completely opposite system of knowledge.
Change habits it’s not easy, and if habits are supported by tradition, sales agent, agronomics schools and current culture, the task can be really tricky.
We need a deep belief in the necessity of a change, preparing ourselves of a future in which oil, fertilizers and soil won’t be as much as today.
In some parts of the world it’s already hard to find manure or compost for the soil, so the knowledge of production tecniques that relies on soil self-fertilization can be vital. We should start to put in practice these knowledge as fast as we can, even in little experimental fields, so that one day we’ll be able to advise farmers on how to alternate their cultivations in a sustainable way, and in every climate conditions.
This research is just at the beginning in many places around the world. We are the members of that group who will be the critical mass necessary to go one step beyond the actual situation. The challenge is to feed a population in exponential growth, while at the same time there is an incredible loss in fertile soil.
Fertile soils are always covered by many different plants, so we could argue that soil needs to be always covered, with its surface full of little plants even while it’s used for agriculture.
If we prevent the problems caused by soil pauperization (erosion, flush and loss of organic matter mainly caused by tillage), the residual organic components left on the soil will be much more than the 5% of nitrogen and other nutrients used by the plants in their growth.
Without disturbing the soil and the dynamics in it, there won’t be any need to use fertilizers, so the work needed to produce compost will be reduced, and thus for any other kind of fertilizer. There won’t be needed any fungicidal or pesticidal threatment.
In synergistic agriculture, fields, gardens and cultivations have to be re-arranged so that the symbiosis between plants, bacteria, mushrooms and every living or mineral elements will create a dynamic synergy: this self-fertilizing process will then grow edible plants for us without pauperizing the soil.
- L'arte di coltivare lasciando fare alla terra, Corso Teorico-pratico, Libera Scuola di Agricoltura Sinergica Emilia Hazelip, tradotto da Fortunato Fabbricini e Anna Fanton dai testi di Emilia Hazelip
- The living soil, Oxygen-Ethylene Cycle, Permaculture College Australia
- L'Azoto e le piante
- Elementi nutritivi, Ferro
- wikipedia:No-till farming