Category Archives: Ecosystem knowledge

Slash and burn

Slash and burn technique is typically a misconduct in agriculture based on the belief that removal of existing vegetation will re- mineralize the soil and benefit to the next succession of plants, having as well the capacity to remove weed and unwanted vegetation and bugs.

Recent studies show that ;

  • the edible nutrients provided by burning the vegetation is coming mainly from the destruction of the living ecosystem of the top soil (bacteria, fungus, …) which release minerals and nitrogen then available for plants. In tropical climate most of these nutrients will be washed away or inside the subsoil and only a small percentage will benefit the newly planted vegetation, resulting in a impoverishment of the soil. Only high plants (trees with deep tap roots) will be able to recover these minerals.
  • the production of charcoal  coming from the burning of the vegetation will not be activated (to be transformed in Biochar) with nutrients since gravity will push these nutrients down or away.
  • The belief that ashes are a concentrated material of potassium needs to be put in perspective since most of potassium will be either evaporated with heavy smokes or washed away by rain. Only charcoal represent a stable and persistent material but needs activation.

These believes come mainly from the mimic of the process used by native Indian in the amazon. The difference is that in the latter case the slash and burn process is part of the rotation of a forest succession with a long period of recovery. Intensive agriculture does not benefits from the slash and burn technique, it only accelerates the death of soil ecosystem then lost of fertility and soil compaction. It is a short term technique creating desertification.

Other drives in this popular belief are that fire can renew life, that slash and burn of an existing forest indeed create an important reserve of nutrients and that fire can remove bugs, undesirable for the newly planted vegetation.

Micro-biology and soil analysis

In these 3 videos Dr Elaine Ingham gives a basic and easy to follow protocol for microbiology analysis of a soil sample, using a microscope of 400x optical resolution. This methodology can be used by growers and do not need expensive equipment. It represents a good alternative to lab sample analysis which can become expensive on the long term and is of limited value.

Microbiology is essential in assessing soil health and fertility. Soil ecosystem analysis is a pretty new domain of study in science and we realize that giving back life to soil is the only solution for sustainable agriculture. The geological and chemical analysis of a soil provides with very limited information and farmers facing soil depletion begin to search for solutions based on organic management and biodiversity increase. Microbiology analysis provides with the necessary feedback to understand soil quality and find adequate solutions for improvement.

Plants – Bacteria – Fungi



It is important to understand that symbiosis is an ancient form of collaboration between various forms of life and key in an ecosystem construction. Only by imagining the long genesis of two interrelated organisms and the tools of interconnection they have developed to collaborate we may start to consider the importance of such mechanisms in a complex ecosystem. Scientists think that plants / mycorrhizae symbiosis started 450 million years ago, when plants migrated to land. Legumes / rhizobia (nitrogen fixing bacteria) symbiosis is more recent; 60 million years old and may have evolved from plant fungi symbiosis mechanism.

In recent studies we learn that fungi and bacteria use a mechanical and chemical stimulation to start a symbiotic connection with a plant.

After reception of the signal by a fungus the plant builds a canal. Once the path is completed inside the plant the fungus is informed, penetrates the plant at canal level and starts to grow inside the plant to form an anchor for resources exchanges.

Such a “civic” processes presuppose an essential and productive collaboration between the 2 organisms and the importance of promoting this type of interconnection in modern agriculture for better yield.

In the case of symbiosis with nitrogen fixing bacteria the plant goes even further and the root hair of the plant when receiving the bacteria signal will trap the colony of bacteria curling the hair root around it.

Plant / Bacteria association

Plants attract bacteria to their root zones by producing “exudates” (sugar = soluble carbohydrates). Bacteria feed on these exudates.

Bacteria are the most protein dense organisms and the main nutrient material of the soil food web. They attract predators; protozoa and nematodes mainly, which feed on them and reject nitrogen and other minerals in surplus.

The minerals are then used by the plant as nutrients. The loop is closed.

In addition to this process 2 important mechanisms play a role in plants and bacteria association;
– Plant symbiosis with nitrogen fixing bacteria (it is the case for leguminous trees and mycorrhizae). In a depleted system (poor in nitrogen) an important ratio of leguminous species is necessary to help plants growing.
– Competition between plants and bacteria to access nitrogen. Here biodiversity is important so that bacteria predators can control this competition.

nutrient-transporters-plant-fungus-soilPlant / Fungi association

The symbiosis with fungi (mycorrhizal), another building block of soil food web, uses as well exudates, this time to trade fungi capacity to extend the plant root system and route minerals, water and phytochemicals over long distances. Fungi have much smaller diameter than plants root which allow them to penetrate the soil more effectively and reach nutrients and water over long distances.

Not tilling allows to respect the fragile network of fungi and increase plant nutrients uptake.

Organic nitrogen, phosphorus, sulfur, potassium, calcium, magnesium, iron and essential trace elements such as zinc, manganese and copper are returned to plant hosts in exchange for carbohydrates.

Fungi plays as well a direct role in Carbon storage and Nitrogen uptake;

There are 2 types of mycorrhizal fungi; ecto and ericoid mycorrhizal fungi, abbreviated as EEMF or EEM, and arbuscular mycorrhizal fungi, abbreviated as AMF or AM.

– Plants absorb carbon dioxide from the atmosphere and release part of the carbon into the soil; this carbon is taken up principally by the AMF, which processes it rapidly and act as a buffer, releasing the carbon gradually to other microorganisms in the soil over time.

– EEMF produces nitrogen-degrading enzymes, which allows them to extract more nitrogen from the soil than the AMF type and gives a competitive advantage to the plants against microorganisms for nitrogen availability. The resulting effect of a better nitrogen uptake is the reduction of carbohydrate decomposition and a higher ratio of carbon per unit of nitrogen.

Fungus and bacteria symbiosis with plant have been identified but many other symbiosis take place in the soil food web, for example nitrogen-fixing bacteria have been found inside ectomycorrhizae mantle.

Flow exchanges in the food web

Plants play 4 essential roles: harvest energy from the sun, fix carbon from the atmosphere, store the energy in the form of carbohydrates and feed the soil ecosystem.
Bacteria play 3 essential roles; store plant energy into a stable organic form (themselves) inside the soil, fix nitrogen from the air and provide food for the ecosystem (themselves).
Fungus play 3 essential roles: store carbon from the plant into the soil, extend plant root system access to nutrients, water and other resources and help nitrogen uptake by the plant

These 3 organisms have as well another important role; degrade matter for nutrients uptake (rocks, carbohydrate, lignin, …)

Bigger the plants (mostly trees and perennials) more energy is harvested from the sun and more influential is the orchestration of the soil life and the resulting fertility of the soil.

Source: Colin Averill, College of Natural Sciences at University of Texas in Austin.
Source: Proceedings of the National Academy of Sciences (PNAS)
Source: Jean-Michel Ané – University of Wisconsin-Madison

NPK management in Organic farming

N=Nitrogen , P=Phosphorus , K=Potassium (from medieval latin Kalium = Pot of Ashes)

In agro-industrial farming these 3 macro nutrients are obtained by chemical synthesis and mineral extraction. It is now acknowledged that mineral fertilizers impact negatively soil life and provoke its death in fine, making the soil not suitable anymore for plant growth (compact and not adapted to nutrients uptake). External resource : Read this amazing article to understand why

Organic and sustainable management of the soil requires additional understanding, knowledge and some ecosystem monitoring. This mindmap gives a synthesis of NPK nutrients role, the consequences if not available and the different means to provide plants with them in the process of organic farming. (click on the mindmap to enlarge it)



Nitrogen is available from the air in a stable chemical form. Bacteria are the main organisms responsible for the capture (fixation) and the transformation of nitrogen into a plant edible form.

Mycorrhizal fungi play an important role by transporting biologically fixed nitrogen to plants in organic form, for example as amino acids.

The predominant form of Nitrogen found in the soil is protein (in organic matter and organisms).

The next predominant form is inorganic; (NO3, NO2-Nitrite, NH4)

Annuals plants need the Nitrate (NO3) form of nitrogen
Perennials need the Ammonium (NH4) form of nitrogen (feeding trees with nitrate can provoke disease)


Potassium is found in the soil in 4 different forms;

– Potassium as a component of soil minerals
– Fixed potassium
– Exchangeable potassium
– Water soluble potassium

The first 2 forms exist in high quantity in the soil (for example clays of type vermiculite, illite and smectite have a lot of fixed potassium). These 2 forms are not directly edible by plants. Fixed potassium is released in low exchangeable potassium conditions, and mineral potassium is released by weathering, which is a slow process. Recent studies show that silt may represent as well an important reservoir of potassium.

Water soluble potassium which is present in compost is edible by plants but subject to leaching when heavy rains.

Organic matter in the soil favors bacterial, fungal and root activity which accelerate the transformation of non edible potassium into edible one. Macro-organisms (e.g. worms) plays as well an important role by preparing the soil for further bacterial and fungus processing.

To summarize Potassium is an abundant resource which need adequate management (living and active soil ecosystem, good monitoring of compost storage and distribution). Culture rotation may not be needed if the soil ecosystem is very alive and active although guilds will increase biodiversity of the soil ecosystem and concur to its fertility.


Phosphorus is the Achilles’ heel of industrial agriculture and the world food supply (read more at Reserves of phosphate in the world are now handled by a reduced number of countries (Morocco and China) and Phosphate peak could happen in the next decades. Although fossil fuel replacement and water recycling are predominant concerns and see a larger spectrum of solution every day phosphorus world depletion is ignored by most of the population and represents the real challenge when it comes to aggro-toxic farming.

The challenge is simple; plants cannot grow without phosphorus and this mineral become a limited resource. The only solution is therefore reducing, recycling and increase phosphorous availability in the soil. At the moment industrial agriculture is posing a threat to humanity by wasting enormous quantities of phosphorus which end-up in the rivers and the sea.


– A vegetarian diet represent 0.6kg of phosphorus per year, a meat-based diet requires 1.6kg phosphorus a year
– reducing the usage of phosphate fertilizers to the exact required proportions


– Recycling farm waste
– Recycling human wastes (sewage) Since crops leave the farm to feed the population it is necessary to get the phosphorus back to the location of production. The most advanced countries in recycling organic matter or sewage already perform such a recycling.

Increase availability.

Phosphorus concentration varies a lot depending on the soils. As for potassium only a small percentage of it is edible (in solution) by plants. Various techniques allows to increase this availability.

– Increase of microorganisms activity (living and active soil, rich in organic matter). They will mineralize organic matter to make phosphorus available and degrade non edible forms of phosphorus compound to transform them in an edible form.
– Phosphate moves very slowly in soils, deep roots and symbiosis with fungus helps in reaching phosphorus in lower layers of the soil. This can be facilitated by a good soil structure and the mix with perennial plants having in average deeper root system.

To go further and generalize; recycling (mainly avoiding leaching) and soil microbiology are the answers to NPK uptake

Dr Elaine Ingham (microbiology world famous expert) goes further;

– NPK is in enough quantity in the soil for millions of years of agriculture. Just is needed a living soil and its food-web to make it available to plant
– Taking care of NPK fertilizing only is a simplistic vision and more we go more we realize the importance of other chemical elements.
– Classical soil analysis inform only on the ratios of directly available minerals not taking into account the reserve of non directly available minerals that the food web can convert into nutrients. As well soils analysis by giving a PH value does not highlight the fact that PH varies in high proportion at different locations of the plant roots; the plant being able to bio-chemically orchestrate the soil ecosystem (including PH) to feed itself and optimize nutrients exchange at root level.
– Compost, which is an inoculum and not a direct nutrient is key in giving back life to the soil.

Here is Dr Ingham at a conference – a dense and extremely interesting talk

Clay – Sand – Silt – Loam and Humus


Clay, sand and silt are definitions of textures. The following picture show respective sizes of these 3 different particles;



Sand, by its comparative large size does not have a chemical valence (capability to interact with charge particles) therefore does not hold minerals in the soil. Water molecules find as well easily their way through sand and get away by the action of gravity. The advantage of sand is its permeability to plants roots which can develop without obstacles. The inconvenient of sand is its poor water and plants nutrients retention. When cultivating with a sandy soil a lot of organic matter needs to be present in the soil to store moisture and nutrients. Biochar helps as well by its structure to mechanically increase water retention in sandy soils.


Clay in agriculture

Clay, on the opposite, is very closed in size to elementary charged particles and react with ionized minerals. Different types of clay have different capabilities to exchanges cations (read more about CEC and measures of fertility) in the soil, playing a role in plant nutrients storage and availability. Usually clays in soils which have been weathered intensely and seen high bacterial activity for long geological periods (e.g. in the tropics) have structures less prone to interacts with minerals. It is one of the reason soils have a lack of minerals in the tropics. These minerals not being held by clay have been washed away by intense rains. In this case organic matter or more precisely humus play the role of nutrients storage with a higher electrostatic capability to interact with minerals than clay. The density of organic matter although is located in the top soil and reduce quickly in lower layers. The greater volume of clay compensate with the reduced capacity to hold nutrients. Plants with deep roots and symbiosis with fungus allow to access this reserve of nutrients in the subsoil.

Clay in building and waterproofing

Clay expand when in contact with water and shrink when getting dry. This particularity impact the different techniques of clay building. Mixing sand and clay using water create a solid aggregate when drying. Sand can be compared to stone and clay to mortar in this mixture.

The flexible expanding and self sealing properties of bentonite make this clay suitable for pond waterproofing. Other techniques using gley (organic material transformed by anaerobic reaction) are a less expensive alternative to bentonite.


Silt is a sediment material with an intermediate size between sand and clay. Carried by water during flood it forms a fertile deposit on valleys floor. Silt is easily compacted.


Loam is a mixture of clay, sand and silt and benefits from the qualities of these 3 different textures, favoring water retention, air circulation, drainage and fertility.


Humus is a highly complex substance still not fully understood. It is a stable and uniformly dark, spongy and amorphous material which come from the mechanical degradation of organic matter. Humus is fertile and gather all properties suitable for optimal plant growth. It is formed by complex chemical compounds, of plant, animal and microbial origin. Humus cannot form in the presence of high levels of inorganic nitrogen, due to the inhibition of the microbes essential to sequestration.

Niche, Cycle and Schedule in Permaculture


Niche and cycles are vocabulary commonly used in biology. Permaculture provide with an additional value to these concepts as “opportunities” to produce value addition to a farm. The term “Schedule” fusion the two concepts to give a better vision of how works nature where fauna and flora (in a systemic environment) are dynamic per nature.

Definition of a Niche;

A niche is the domain of presence (or function) of a given organism within its ecosystem. It includes the areas related to the search for food, shelter and reproduction. A species’ niche includes all of its interactions with the biotic and abiotic factors of its environment. A niche involves one organism. In Permaculture a Niche is defined as an opportunity in Space.

Definition of a Cycle;

An ecological cycle is a self-regulating process that recycle earth resources (e.g. water, nitrogen, carbon, …). For example and to simplify; flamingos eat Spirulina and produce dejection which will be used as a nutrient by Spirulina. If entropy is associated with energy dissipation and chaos, cycles allow to reduce this effect and conserve energy by re-using (recycling) resources and energy. As a consequence cycles can be considered as producers of reusable resources and are considered a yield (available resource) in Permaculture. A cycle involves one or more organisms (biotic) and abiotic resources. In Permaculture a Cycle create opportunity in Time.

Definition of a Schedule in Permaculture;

A schedule is the sequence (or set) of intersections between Niche and Cycle; A schedule element is performed by one organism fulfilling one function of a cycle in time inside a niche. In Permaculture a Schedule is defined as a set of opportunities in Space/Time.

Permaculture Vocabulary, Terms and Concepts

Adobe – Clay – Cob – Barro – Sustainable Building

Adobe : A mix of clay and sand used as a building material, typically in the form of dried bricks. See how applied concretely here.

Adobe building is part of a habitat settlement in Permaculture.

Aggregates (soil) or lumps

Soil aggregates are groups of soil particles binding together. They are a sign of soil fertility and come from different processes; sticky substance excreted by bacteria and fungi, fungi hyphae (filaments) and root hair tying soil particles together, sugar excreted by roots binding minerals together, oxides acting as a glue, electrostatic forces.


Aggregates provide porosity, water-holding capacity and a stable environment for microorganisms. Unless soils are actively aggregating, they will not be fixing significant amounts of atmospheric nitrogen or sequestering stable forms of carbon. External resource : see an illustration of aggregate by Rudy Garcia, State Agronomist with the USDA Natural Resources Conservation Service in New Mexico.

Permaculture uses aggregates as a sign of fertility in the process of soil observation.


Agroecology is a domain of science which studies the ecological processes at work in agricultural systems. See the comparison between Permaculture and agroecology.

Permaculture is a concrete application of agroecology in addition with habitat production and ethic statement.

Agro-toxic farming

Non sustainable farming based on simplistic knowledge of biological and ecosystemic processes. Agro-toxic farming survives because of government subsidies in a geopolitical context and on the parasitism of environmental services like water availability at low cost, subsidized fossil fuel and public funds for health care resolving side effects of farming toxicity, pollution and lack of nutrition. Agro-toxic farming requires between 10 to 20 calories equivalent petrol to produce 1 calorie equivalent food.

Agro-toxic industry is a monopolistic sector intimately related to bank and finance, political lobbying, fossil fuel and chemical and pharmaceutical industry. As such a transition to a different model seems difficult and is obstructed by

– the lack of awareness of alternative models (maintained by this monopolistic model)
– food is considered as a commodity preventing a transition toward more ethic regulation (see external resource)
– the poor knowledge of soil and ecosystem processes both in industrial farming and in small farms in developing countries

Side effects like geopolitical dominance in genetic engineering and commodities exchanges speculation disturbs the world chessboard and maintain this outdated technology. Consumerism and marketing processes maintain as well uneducated population in the belief that no concrete alternative exist.

Transition drives toward ecofriendly practices may include

– Crisis (famine, large scale diseases, water shortage, dependency outbreak between dense urban centers and countryside, …)
Ecosystemic and agroecology studies in science
– Organic agriculture in search for optimization
– Popularization of Permaculture know-how and public awareness of alternative system
– Creation of alternative local distribution channels supported globally by internet (see external resource) empowering small organic farms
– Reorientation of genetic selection toward perennials (see external resource)
Urban Permaculture
– Development of free from patent seeds networks

Permaculture intends to use no artificial (petrol based) calorie input (only sunlight) to produce food at the same time as to improve the ecosystem fertility.


Allelopathy is a biological interaction between organisms using biochemicals that influence the germination, growth, survival, and reproduction. The allelochemicals can have beneficial (creating synergy) or detrimental (aggressive or defensive mechanisms) effects on the target organisms or ecosystem.

Permaculture intends to include allelopathic mechanisms in the ecosystem management either to increase beneficial interactions or control invading species.


Alcohol may be considered as an organic derivative of water (H2O) in which one of the hydrogen atoms has been replaced by an alkyl group (molecule made of Carbon and Hydrogen atoms), typically represented by R. Lignin are polymers (complex structure) made of aromatic alcohol. Alcohol is not a carbohydrate.

Annual plant

An annual plant is a plant that completes its life cycle, from germination to the production of seed, within one year, and then dies. It is based on a short cycles requiring a lot of nutrients to propagate.

Although agro-industry has been developed on a model of annual crops production, Permaculture tends to find a balance between annuals (energy demanding) and perennials (energy accumulating) in order to ensure the sustainability (permanence) of the ecosystem.


Biochar means charcoal enriched with biological nutrients. Its properties have been used for thousand of years by the amazonian civilization to substantiate (through soil fertilization) an intensive and productive agriculture (the necessary foundation of a civilization) in an ecosystem having poor soil. The addition of biochar to the soil create a rich and black earth called ; “A terra preta dos indios” meaning ; “the black earth of the Indians”. In the amazon the fertility stands usually up the ground in the different stages of vegetation. Every particle of biomass falling to the ground (if not diverted by the forest) is quickly degraded and used by fungus and bacteria, and end up as nutrients for the superficial roots of the giant trees. These giant trees do not really count on the very thin layer of top soil but survive by complementing there diet with very deep roots getting sparse nutrients from the deep and poor degraded soil. Biochar is everyday more famous and many countries envisage the production of this material (for agricultural purpose) as byproducts of energy production in a circular economy perspective.

The properties of biochar are (being still under the scrutiny of a growing population of biologists);

  • The difference between charcoal and biochar is the inclusion of biological nutrients inside the charcoal to get the biochar. If you put charcoal right into the soil it can suck the nutrients and have a negative effect on the plants. Amazonian Indians certainly added these nutrients by using organic waste from everyday life (organic garbage from the kitchen, urine, etc.)
  • Charcoal has a large wall surface area inside the cavities where microorganisms can find a habitat and protect themselves from the effects of heavy rains and biological cycles (being pray in the food web). A charcoal spoon has a wall surface area equivalent to a football stadium. Adding charcoal to a soil rich in clay will improve drainage, adding charcoal to a sandy soil will reduce drainage. In each case it has a structural benefit to handle more water available and help the distribution of soluble nutrients to plants.
  • Charcoal (or pyrolyzed biomass or pyrogenic carbon) is a very stable structure of carbon. What never appears in scientific studies is the question of the use of this carbon as a nutrient for plants, fungi and bacteria.


Read more about biodiversity here. Biodiversity is not a trivial concept. A bird could be considered as a flying ecosystem ! Therefore defining the complexity of our biological environment requires some steps back and smart consideration.

Here is an example of the interrelations at play in a diversified environment (biodiversity completion) when all the puzzle pieces are present;

Permaculture relies on biodiversity to ensure ecosystem fertility, productivity, stability and resilience.


Organic matter dead or alive (based on the chemistry of carbon) such as organisms (plants, microorganisms, animals,…) , wood, mulch, agricultural crops or wastes, etc… Biomass originates from the photosynthesis and as such stores the sun energy harvested by plants through photosynthesis. Petrol, bacteria, humans, trees have an inherent biomass.

In Permaculture biomass accumulation is the sign of fertility and sustainability.


Biomimicry is mimicking nature to innovate in the creation of sustainable products, services and environments. It goes from simple inspiration to engineering accurate reproduction of the exact mechanisms observed in nature.

Permaculture uses biomimicry mainly in its ecosystemic dimension (patterns, functions, relations, simulations).


Bokashi composting is an anaerobic degradation using specific microorganisms as an inoculum. It needs a closed recipient and allows to degrade meat and diaries which represents its main advantage in an urban environment with no presence of omnivores (like chicken) in the food chain able to recycle meat and which excrement can be usefully recycled.

Carbohydrate (Carbs for short)

Carbohydrates include sugars, starches, cellulose and many other compounds found in living organisms. Carbohydrates are also known as sugars. The central structure of carbs are a chain (sometime forming a cycle) of Carbon and Oxygen atoms, surrounded by Hydrogen (twice the number of carbon) atoms. Alcohol is not a carbs.

Permaculture aims to generalize and improve the process of sun light (energy) transformation into carbs production as a way of energy conservation for direct or subsequent food and byproducts production.


Compost is an inoculum based on microorganisms and associated foodweb. Read how to make compost.

Permaculture uses compost as a way to nourish the soil ecosystem, which itself will nourish the plants and animals of the farm.

Closed Loop – Cradle to Cradle – Circular economy

Closed Loop : A processing system in which effluents are recycled.
Cradle to Cradle : A biomimetic approach to the design of products and systems. It models human industry on nature’s processes viewing materials as nutrients circulating in healthy, safe metabolisms.
Circular Economy : An industrial economy that is, by design or intention, restorative and in which material flows are of two types, biological nutrients, designed to reenter the biosphere safely, and technical nutrients, which are designed to reenter the industrial process of production after usage.

The 3 terms are slightly describing the same concept. As Cradle to Cradle is specifically mono-company, Circular Economy involves a set of partners related by financial interests contributing to a Cradle to Cradle finality. Difference between Cradle to Cradle and Circular Economy

Closed Loop encompasses the capacity of energy saving since, in thermodynamic, a closed system is conserving energy.

In opposition to the model Cradle to Grave (animal like) the model Cradle to Cradle intends to propose a solution to make the industrial process (driven by neurotic consumption) more sustainable.

Permaculture uses natural (biological) closed loop processes to save energy and optimize farm production. Read more about the link between Permaculture and Cradle to Cradle. Biological Closed loops are highly efficient in harvesting and storing sun energy. Over time they produce excess which requires maintenance. This maintenance is paid off by biomass overproduction (carbohydrate energy which will be used somewhere else). In case of technical Closed loop; time produce degradation, maintenance is then resource intensive and has a negative balance in term of incoming and outgoing flows of material (e.g. equipment replacement), unless built on site with on site materials.


An ecosystem is both a system with boundaries and crossing flows and the biological community of interacting organisms it shelters. The complexity of an ecosystem increase exponentially with the number of the type of elements it contains. Systemic approach is usually used to handle this complexity.

Permaculture is the management of a productive and biodiverse ecosystem.

Ecotone, edges and ecosystems interfaces

Ecotone : the transition zone along the edges of two adjacent ecological communities, where one ecological communities meets the other (e.g. the area between forest and grassland, between land and water, between two different areas separated by an edge, …). The transition from one ecosystem to the other can be gradual or sharp.

At the edge of two overlapping ecosystems, you can find species from both of these ecosystems, as well as unique species that aren’t found in either ecosystems but are specially adapted to the conditions of the transition zone between the two ecosystems.

There is a greater diversity of life in the region where two adjacent ecosystems overlap.


It is the reason why Permaculture involves the creation of as many interfaces as possible. The multiplication of niches and species increase the number of Schedules therefore the productivity of the system. Additionally edges play a major role in harvesting resources (rain, sun, wind) which can benefit or help specialize the sub-ecosystemsas well as increase the interactions consumer/resources existing in the foodweb.


A community whose inhabitants seek to live according to ecological principles both in the setup of their habitat and the way of living.

Permaculture and Urban Permaculture design principles are often used as guidelines for the settlement of such communities.


Goldstein initially define emergence as: “the arising of novel and coherent structures, patterns and properties during the process of self-organization in complex systems”.

Synergy supported by complex system interactions produces emergence. E.g. A life form is more than a collection of atoms and molecules, intelligence and conscience is more than a collection of cells, an ecosystems is more than a collection of plants and animals. For example the resilience in an ecosystems is an emergent function supported by the biodiversity.

Permaculture by using ecosystems synergies aims to produce human food as an emergent function of a natural ecosystems.

Exudates (see Root exudates)


Wikipedia definition : A fab lab (fabrication laboratory) is a small-scale workshop offering (personal) digital fabrication.

Fab-lab are open-source with design sharing ambition. Initially not a productive platform, intending to support ultimate customization, the movement has however seen some shifting here and there to adapt to local need ; for example creation of contextual tools to support local industry, agriculture, services, …  Map of fab lab in the world.

Permaculture is intensively connected to the development of alternative ways of production, being aware of the need for autonomy and self sufficiency and giving importance to the necessity of re-acquiring technological knowledge. At the moment Permaculture use low-tech products however with fab-lab development we could see emerging an increased usage of more sophisticated technologies still keeping control on the “know-how” . See more about Permaculture and new technologies


Foodweb is a set of organisms related by predator-prey, consumer-resource interactions; the entirety of interrelated food chains (including symbiosis) and territory management in an ecological community.

In the old time things were much simpler ! We were talking about food chain. A maybe narcissistic but working vision were human were at the top of the food pyramid. Herbivores, carnivores, carnivores of carnivores, then finance and market, a very hierarchical and predatory perspective.

However what made human successful was not the capability of an individual to be the strongest but of humanoid groups to work in collaboration. This ecosystem rule is supported by the concept of food chain, a much more realistic and complex set of interactions.

A virus can kill you and they are not on the top of the pyramid, bacteria can be good guys or bad guys, plants may work together with fungi, human stomach requires bacteria for digestion, scavengers do not exist in the food chain, etc,

It is about ecosystem and complexity, it is about biodiversity and the necessity to rely on different forms of life to maintain the system operational.

The interactions are intense and multiple; repellents and inhibitors, toxins, parasitoids, pathogenstraps baited with pheromone, jasmonates, enzyme-substrate interactions, volatiles and soluble chemicals, entomopathogens … the list is endless. Relationships between organisms may include competition, symbiosis, commensalism, parasitism, collaboration, etc.

The soil ecosystem is a perfect example of the foodweb complexity with bacteria, fungi, protozoa, nematode, arthropods, worms, mollusks, etc. and the plants which orchestrate this biodiversity through their exudates.

The Foodweb is part and is related to the complexity of an ecosystem (see systemic approach).

Permaculture intends to understand and/or integrate the complexity of the foodweb to create a sustainable ecosystem.


Glomalin was dicovered recently. It is a glycoprotein produced abundantly on hyphae and spores of arbuscular mycorrhizal fungi in soil. Glomalin is a significant component of soil organic matter and act to bind mineral particles together, improving soil quality. Glomalin is located on the outside of hyphae, and scientists suppose this is how the hyphae seal themselves so they can carry water and nutrients. Glomalin has been investigated for its carbon and nitrogen storing properties, including as a potential method of carbon sequestration.

Higher plants

Plants of relatively complex or advanced characteristics, especially vascular plants.

Permaculture favors the establishment of higher plants since they form the structure of a more perennial and sophisticated ecosystem.


Manure coming from human. See Dry toilets, Biodigestor evapotranspiration, Banana circle.

Permaculture intends to recycle this type of manure.

Humus – Described here


Each of the branching filaments that make up the mycelium of a fungus.

Keypoint and Keyline

The keypoint is the transition part of a slope between the convex and concave curbs.
keypoint-and-keylineA keyline is a design using the adjacent set of keypoints following a contour (sometime formalized by a swale) and distort the contour lines to introduce a gradient to force a light water runoff (ditch) in a way that water will reach the drier zones by gravity. Drier zones being at the top of the ridges. The keylines will compensate the usual behavior of water runoff to find the quickest way to the valley.

Keypoint is used in Permaculture to locate water run off reservoirs for zone 0. Up the hill from the keypoint the construction of a dam would demand high quantity of resources to build a dam and little result in water storage. We assume here that Zone 0 is located on the upper part of the concave slope just beneath the water storage for landscape architecture optimization (See zoning in Permaculture).


Plants forming a symbiosis with nitrogen fixing bacteria (most of them have this particularity). Leguminous by there action of soil fertilization are qualified as support species. Certain leguminous may be considered as well asproductive species since they produce edible beans and peas, high in proteins.

Leguminous plants occur naturally in depleted areas since they are able to compensate the lack of nitrogen by their symbiosis with nitrogen fixing bacteria. The vigor (dynamic building capability) given by the nitrogen allows them to efficiently harvest and make edible the remaining minerals necessary for their growth.

In Permaculture they are important elements used to regenerate the soil ecosystem and may be planted in a proportion of 90% of the total plants (over stacked) in the first years of rehabilitation. In a mature and more sophisticated ecosystem this ratio may be reduced to 10% to 20% of the biomass by pruning and removing of the leguminous plants for mulch production and nitrogen release.


A complex organic compound that binds to cellulose fibers and hardens and strengthens the plants. Lignin is a polymer consisting of various aromatic alcohol (non-carbohydrate). Fungi is the most efficient microorganism for lignin degradation.

Loam – Described here


An organic material (such as decaying leaves, bark, paper, …) spread over the soil to enrich and insulate it from hit and drought.

Permaculture makes an intensive use of mulch, both for soil ecosystem enrichment and water conservation.

(Human) Microbiome or Microbiota

The human microbiome is the set of microorganisms that resides on or within any of a number of human tissues and fluids. The microbiome is now considered a human organ with much more genetic complexity than human genome, with genetic transfer between human genome and the microbiome and genetically imprinted human mechanism participating to microbiome settlement (e.g. a mother milk may contains substance not intended to support directly the baby but instead to support its microbiome).

Permaculture give genuine importance to the microorganisms activities considering the set of microorganisms to be the foundation stone of an ecosystem (here the human body may be considered an ecosystem integrating billions of interactions between organs and the microbiome). In this perspective the biodiversity produced by agroecological farming applies at microorganisms level with the necessity to enlarge the spectrum of nutrients necessary to sustain microorganisms.


Mycelium is the vegetative part of a fungus, consisting of a network like structure. The diameter of a mycelium branch is micrometrical, giving to the fungus the capability to navigate in the soil structure where plant root may encounter obstacles due to their much bigger size. (See Mycorrhiza)


Permaculture favors the development of mycelium (fungus) in many instances ; composting, mycorrhiza, mulching, …

Mycorrhiza (plural noun: mycorrhizae)

From Greek; Myco : fungus and Rhiza : root. A fungus that form a symbiotic association (through mycelium) with the roots of plant. Most higher plants have developed this capability (Read more about this amazing symbiosis.) Mycorrhizal help in the nitrogen cycle by transferring liquid carbohydrates to nitrogen fixers and transport biologically fixed nitrogen to plants in organic form.

Permaculture relies in a great extend on the synergy produced by this association allowing the sharing of soil ecosystem resources and improving plants growth and resilience. The development of mycelium is respected by non disturbing the soil structure (non plowing, non tilling). Mycorrhiza reduce nitrification, de-nitrification, nitrogen volatilisation and leaching. Additionally, the storage of nitrogen in the organic form prevents soil acidification.


Finding an alternative with the most cost effective or highest achievable performance under the given constraints.

Agro-toxic is the iconic example of a non optimized process, spending 10 to 20 calories of petrol equivalent to produce 1 calorie of plant.

In our limited world “given constraints” means “sustainability”, meaning using what we need of our planet assuming our children will have enough to survive and … hopefully … to live and thrive, themselves, on a sustainable way. It is a cycling process.

If you want to go quick and dirty use fossil fuel (which is maybe a solution in some limited cases) if you want to go securely, planet wise, you need to integrate environmental constraints in your system of rules.

Permaculture is about optimization and interacts with the flows of energy (sun light, photosynthesis, wind, ..) and resources (water, natural fertilizers, mulch, minerals, etc.) in a sustainable and optimized way. The optimization comes from the design of functions and interactions in a way that will help develop closed biological loops for human food and the environment. The biological processes would be maybe 1000 times more effective in energy usage (assumption impossible to verify but my own guess in average) than technical closed loops and can be made perennial per design.

Organic agriculture

Organic Agriculture is a production system that sustains the health of soils, ecosystems and people.

It is evolving to rely on ecological processes, biodiversity and cycles adapted to local conditions.

It still uses inputs (organic) to boost production, and has a limited dimension of optimization.

Permaculture may be seen as an optimized way to do organic agriculture. Permaculture is said “Information intensive” since it aims to understand and design the ecosystem and its complexity. Organic agriculture is said “labor intensive” because not really optimized and architectured in a way so to use all natural leverage for food production. Agro-industrial or agro-toxic agriculture is said “fuel intensive” since it is based mainly on oil consumption.

Perennial plant (Perennial for short)

A perennial plant is a plant that lives for more than two years. Perennials have long cycles of growth and form the permanent structure of an ecosystem . They produce more than annuals in comparison to the labor and input required for their growth. They have a strategy of living based on slow growth and fertilization of the ecosystem they belong to through systemic mechanisms (sugar release, carbon sequestration, symbiosis with fungus, animal habitat, moisture harvesting, etc). (Perennials are opposite to Annuals)

Permaculture farm built their ecosystem on a biological structure favoring perennials.


Photosynthesis is the process by which plants mostly create biomass. It is a chemical process that uses sunlight to turn carbon dioxide into sugars (a biological source of energy and nutrient material) and release oxygen.

Permaculture intends to maximize the photosynthesis capability of a farm and conserve the biomass produced through closed loops.


Convert (waste) into reusable material.(See closed loop)

Down-cycling (an anthropomorphic concept) is recycling a product into another one with less value. When recycling paper the cellulose fibers get shorter inducing a lost of paper quality therefore it can be considered as a down-cycling process.

Up-cycling is recycling a product into another one with more value. E.g. Using the byproduct of digestion (manure) we may create compost which will fertilize a vegetable garden.

Permaculture aim is to apply Up-cycling as much as possible in every step of transformation.


The ability to self recover from illness, negative impact or wound.

Permaculture relies on the resilience of natural and bio-diverse ecosystems to ensure food production and habitat stability. Examples of negative impacts; pest, climate change, fire, flood, drought, extreme temperature, air and water pollution, etc.)


The region of soil in the vicinity of plant roots in which the chemistry and microbiology is influenced by their growth, respiration, nutrient and phytochemicals exchange.

Permaculture gives a preponderant attention to the soil which fertility is orchestrated by the plant root system and its associated rhizosphere.

Root exudates

Root exudates are mainly sugars, amino acids, and organic acids produced by the plant to maintain and support a specific diversity of microorganisms in the rhizosphere. They play a major role in the mobilization of scarce soluble nutrients in the soil. Sugars and other nutrients feed the bacteria and fungi which in exchange store and/or provide with various resources needed by the plant.

Root exudates prevent as well pathogen attacks by the direct secretion of phytochemicals that repel, inhibit, or kill pathogenic microorganisms in the rhizosphere and by orchestrating the symbiosis with fungi which participate as well to the process of plant healing by gathering adequate biochemical resources.

Root exudates are not only diverse in their composition, but also very dynamic, adapting to the plant needs depending on plant or context cycles (disease, seasons, weather, fruit production, etc.)

Permaculture gives special attention to the mechanisms at the source of soil fertility and emphasizes the importance of perennial plants, the most productive in root exudation and soil ecosystem stability due to the permanence in maintaining and supporting the soil ecosystem .

Silt – Described here

Schedule in Permaculture

A schedule is the presence and utilization by animals, microorganisms, plant and optionally human of an area of the ecosystem for a certain period of time. A schedule may represent an opportunity in the sense of a service or value added product. E.g. Eggs laid by the chicken harvested by the farmer in the chicken coop; Dragonfly eating a mosquito close to the pond; dragonfly larvae eating a mosquito larvae inside the pond, etc ….

A schedule is an event in a sub-ecosystem agenda.

Convergent point of niches and cycles in a certain point of time and space, creating opportunities.

Initially defined by Bill Mollison and described more in details here.

Permaculture is about creating opportunities through Schedules management and optimization.

Sectors in Permaculture

A sector is the main tool used in Permaculture to identify and harvest natural flows (of energy and resource) entering the property. It is used as well to identify negative impact and mitigate them. In term of design a sector is the 4 dimensional angle taken by an input flow in the ecosystem of the farm. A flow of energy (e.g. sun) or resource (e.g. rain) will enter the property having a spatial angle. Angle which may vary over time. The most used example is the course of the sun. The sector “winter sun” has a specific horizontal and vertical angle and vary during the day. The constituents of the farm ecosystem will be located in order to optimize the energy intake and resources distribution and deviate the pollution.

Stacking Function

An elements in the farm serve more than one function. E.g. Chicken produce eggs, manure, control bugs, etc… . By favoring the more multifunctional elements we increase the quantity of positive interactions and incidentally the yield per specific area. More about stacking function

Permaculture orientates (in zone 1 to 4) the biodiversity in a way as to maintain a “natural” number of elements and increase the number of positive interactions. The idea is not to overwhelm the system with an artificial biodiversity which could be difficult to maintain but find the best ecosystem “skeleton” based on the synergies produced by the interactions.

Sustainable agriculture

Sustainable agriculture (including silviculture) is the production of food and plant and animal byproducts using farming techniques that respect the environment and that meets the needs of the present without compromising the ability of future generations to produce their own food and associated byproducts.

Permaculture proposes a concrete model for sustainable agriculture development, both in countryside and in urban areas.

Swale and Contour line

A long depression in the soil (of a slope, usually) following a contour line, designed to collect or redirect water and reverse erosion. Read more here.

A contour line is a line on a map joining points of equal height above or below sea level.

Permaculture farms are usually built on lands having slopes in order to take advantage of the gravity in harvesting water and other resources (mulch, sand, manure, etc…). In many instances if the land has been deforested the water run-off has removed the top soil through erosion. Swales are the main tools to reverse this erosion and recreate the top soils.


The interaction of two or more elements to produce a combined effect greater than the sum of their separate effects. Synergy is the spontaneous apparition of a value addition and often described as 1+1=3. An example is the association of a leguminous and a fruit tree. The fruit tree will grow better thanks to the nitrogen fixing of the leguminous and maybe its wind break and moisture capability. The fruit tree will produce fruits which surplus falling on the ground will provide with sugars to the soil ecosystem and attract birds producing manure and controlling the bugs. The result is not 1 leguminous + 1 fruit tree, it is the sum of them + additional growth, fruit production, health, increased biomass and fertile soil.

Permaculture is a synergistic agriculture

Systemic approach

Domain of science design for complex systems (ecosystems , virtual systems, economical systems, …) analysis based on observation, experimentation, simulation and pattern recognition. Read more here about its used in Permaculture.

The Systemic approach is an holistic approach, meaning applying to the whole set of constituents interacting with the studied object. It is fundamentally in opposition with the reductionist approach which as driven the development of western science till now. The reductionist approach has given birth to extraordinary developments in science like quantum physics but fails to support and give tools for the analysis of complex environments where elementary objects have numerous relationships creating a phenomenon called emergence. The systemic approach is not intuitive and has been created artificially together with its methodology and analytical tools in the objective of handling complexity. To do so it’s methodology is essentially based on observation and simulation (experimentation) of systems considered as “black boxes” in the initial steps of analysis.

Systemic approach is not to be confused with Systematic approach which is “Done or acting according to a fixed plan or system; methodical”.

Permaculture uses a systemic approach to design productive ecosystems . Analytical approach is used at element level and less determinant in the global strategy of landscape architecture.


Thermodynamics is a branch of physics related to heat and temperature and their relation to energy and work (2 different notions at the source of modern science). It defines measures such as internal energy, entropy, and pressure used to describe a system and the flows of energy it exchanges with its context.

The first law of Thermodynamic is : Nothing is lost, nothing is created, all is transformed.

This principle may be seen as the main revolution in the history of science, first as an emancipation from religion and metaphysics, second by its implication in every domain of science, quantum theory and General relativity included.

The second law of Thermodynamic (Entropy) is : a system tends to find the lowest state of energy in average.Entropy is related to chaos, meaning the destruction of the structure and the dissolution of the world. In modern physics some theory stipulates that Time dimension is less fundamental than Entropy and could be a sub-product of Entropy when passing from the quantum world to the statistical, macroscopic one. Scientists agree on a more subtle notion; the conservation of information. While entropy (chaos) dilutes the world, information still remains present, you would just need to reverse engineer its previous structure.

Since Permaculture aim is to optimize the transformation of sun energy into food and habitat mainly through photosynthesis, thermodynamic is used as a conceptual support to understand the management of flows of energy (mainly sun and derived products like organic matter) and resources (water, minerals, etc…). Permaculture yield can be seen as equivalent as its capacity to slow down the effect of entropy in a human perspective.

Entropy cannot be reversed, it is the human/universe destiny (dilution through universe energy consumption and expansion), only slowing down its effects can be tempted to make our planet more sustainable on the long run. For example Agro-toxic farming is an “orgy of entropy”, champion of short term production through fossil fuel consumption leaving the planet more depleted each and every day resource wise and not renewing energy availability.

Urban Permaculture

Urban Permaculture is an adaptation of Permaculture to cities environment. It gives design guidelines to ensure proximity, public transportation, energy efficiency using natural mechanisms, food production, vegetation introduction and social, cultural and economic values based on ethic.

Vascular plants

Plants that have lignified tissues for conducting water and minerals.

Permaculture : See higher plants

Zones in Permaculture

The main objective in farm zoning is to optimize the location of the functions and elements in order to ease human logistic and energy and resources distribution. More about Zones

Zoning is one of the main farm design tool in Permaculture, together with sectors and slopes