Design
The twelve principles
Based on ethical principles, Holmgren defined 12 permaculture design principles. Focused on systems theory, they serve as general guides to orient ourselves within the enormous natural and social complexity when developing a sustainable system:[16].
Zones
Zones are a way to intelligently organize the human environment according to the frequency of your needs or care for your plants and animals. The most frequented areas throughout the day should be located in the areas close to the home, that is, in zones 1 and 2. Those that are visited somewhat less frequently in zones 3 to 5.[17].
Layers
Layers are one of the tools used to design functional ecosystems that are sustainable and of direct benefit to humans. A mature ecosystem has a large number of relationships between its component parts: trees, understory, ground cover, soil, fungi, insects and animals. Because plants grow to different heights, a community of diverse life forms is able to grow in a relatively small space, as each layer is stacked on top of each other. In general, there are seven recognized layers in a food forest, although some permaculture practitioners also include mushrooms as the eighth layer.[19].
border effect
The edge effect is when two very different systems meet and an area of intense productivity and useful connections is created. An example of this is the coast; Where land and sea meet there is an especially abundant area for human and animal needs. So this idea is developed in permacultural designs such as spiraling herbs or creating ponds that have undulating shorelines rather than a simple circle or oval (thus increasing the amount of edge for a given area).
However, cases have been documented in which sometimes the edge effect when an abrupt change occurs - from forest to grassland for example - can lead to greater replacement of species, in addition to a somewhat abrupt variation in the microclimate. It has been observed that there is greater conservation when the change is less abrupt, for example when a forest borders a scrubland.[21][22].
Guilds
There are many forms of guilds or associations, including guilds of plants with similar functions (which could be exchanged within an ecosystem), but the most common perception is that of a guild of mutual support causing a symbiosis. Such a guild is a group of species in which each provides a unique set of diverse functions that support each other in a symbiotic way. Mutual support guilds are groups of plants, animals, insects, etc., that function well together. Some plants can be grown for food production, some have taproots that draw nutrients from deep in the earth, some are nitrogen fixers, some attract beneficial insects, and others repel harmful insects.
When this group of elements are grouped together and mutually benefit from each other, these plants are said to form a guild.[23][24][25].
Biodiversity
Monocultures are artificial systems created by humans to fit with the model of social specialization, thus creating large areas of monoculture that have been shown to be not ideal, since they do not fit with the ecosystem or adapt to it. A pest or disease of a certain species makes the monoculture not very resilient "Resilience (ecology)"), since it does not have plants nearby that associate or form a guild with them in order to protect themselves, as was the case with the phylloxera plague that devastated vine monocultures throughout Europe.[26].
Therefore, the association of crops and the use of animals is necessary to take advantage of symbioses, imitating nature, achieving systems that are resilient against pests and that self-regulate.
Soil management
For a system to be able to self-regulate and achieve stability, it needs the soil to be "alive", that is, it contains the maximum number of beneficial microorganisms and insects such as worms that allow it to aerate, as well as fungi that create mycorrhiza, which is what ultimately helps the proper development of plants. To achieve healthy soil, it must be protected from both the sun and the rain, since if it is bare, solar radiation and the impact of raindrops destroy the microorganisms and fungi that live in the soil. The forest, scrubland and other natural environments manage to protect it naturally with the fallen leaves of trees and bushes. Humans manage to imitate this by using some type of mulch that will vary depending on the climate. For example, in areas with a fairly warm spring and summer, such as in Mediterranean or continental Mediterranean climates, it is advisable to use straw. In a somewhat colder climate, straw or another similar type of mulch will cause excess moisture, so it is advisable to use compost instead.
Another way to protect the soil is through plant cover. These covers require periodic mowing that produces debris that when accumulated serves as mulch,[27] or the use of livestock to graze and thus trim the grass.
Something important to keep in mind is the contribution of organic matter. In bare soil that lacks life, nutrients and organic matter are of little use, since when it rains they go to the deepest parts of the soil, being lost in what is known as nutrient washing. On the other hand, in living soil, microorganisms eat these nutrients and slowly release them through their respiration or when they die. In this way, the organic matter serves as food for them to continue maintaining a good balance in the soil and the plants ensure that their nutrients do not disappear and have them available when they need them.
Another aspect to take into account is the structure of the soil. This can be more clayey, silty or sandy and in terms of its pH it can be an acidic, neutral or alkaline soil. In the same way that you have to take into account the climate to know what type of species to grow, it is also important to know the type of soil you have to find out if the soil can be fertile or simply arable and to know what type of plants would adapt best. If the soil is not very suitable for cultivation, it can be corrected by providing large amounts of organic matter and mulching the soil. Sometimes if the pH is not neutral[a] and difficult to correct, it may be advisable to adapt to the terrain and plant acidophilic or alkalophilic species as appropriate.
Another fundamental aspect of healthy soil is mycorrhiza. This is the connection that fungi establish to create a symbiosis with the roots of plants, shrubs and trees. The fungus provides water, minerals and nutrients to the plant from places inaccessible to it. In exchange, the fungus obtains carbohydrates and vitamins that it would not otherwise be able to obtain. It also allows plant species to communicate with each other, exchanging information and nutrients. Unprotected soil limits or directly kills a mycorrhizal fungus.[28].
Use of animals
Animal management in permaculture is key to maintaining a sustainable system. Earthworms and beetles that produce natural aeration of the soil, butterflies and bees that pollinate, chickens, rabbits, sheep, goats, pigs and cows that help fertilize the soil with their waste, in addition to stirring it a little with their claws and hooves (bioturbation), favoring microbial life in the soil as long as it is not overgrazed. Precisely to avoid this overgrazing, permaculture contemplates the use of mobile chicken coops or a zone rotation system in the case of larger animals.
Their activity also produces many other beneficial effects such as good nutrient recycling, as long as they are well fed with organic products, good soil drainage, clearing and limiting adventitious grasses, consumption of fallen fruits spreading their seeds, limitation of pests, etc.
There are also silvopastoral systems that take advantage of the cultivation of certain types of trees so that they can provide food to livestock for months for free, with the animals feeding on their fallen fruits. For example, pigs can benefit from holm oaks (dehesa), sheep from pear and apple trees, and cows from mango trees.[31].
Some fish species also contribute to the proper functioning of a pond or marine permaculture system.
Energy
Permaculture advocates the greatest possible conservation of energy that enters a system, whether in the form of sun, water or wind, among others. A system has to produce more than it spends for it to be sustainable, therefore the good positioning of certain trees and plants is essential so that the sun penetrates in winter in the desired places or that they provide shade in summer in those same places, in this way a house could be in front of a deciduous tree facing the midday sun (to the south in the northern hemisphere and to the north in the southern hemisphere) and receive all the necessary sun in winter as the tree does not have leaves and in summer be protected from it thanks to all the foliage that the tree has. Another good way to take advantage of the sun is by placing solar energy panels on the roofs and storing it in batteries as electrical energy.
To take advantage of the wind, small domestic windmills can also be placed and stored in batteries and to protect against it, place "windbreaks" which are lines of evergreen trees (such as cypresses) in places where the coldest and most intense wind comes from.
For water, level ditches or keylines can also be designed so that the land itself absorbs it and does not waste it. In this way, the water accumulated in the subsoil can be used by trees in drier periods. To prevent water from escaping from the system, you can design the placement of small mounds on which you can also grow crops, called Hügel (hill in German) in those places where water escapes. The water that falls on the house or any other building can also be stored in tanks through a system of gutters that prevent it from spoiling.[32] After having been used and contaminated at home, it can be purified again and reused to water the garden or to supply a natural pool.[33].
Architecture
Permacultural design also concerns the home itself and auxiliary buildings within a farm. It is recommended that the home itself be within the system that a permaculturist manages in order to take advantage of the zone system (from zone 1 to 5). Therefore, the house becomes ground zero from which we start towards the different areas in order to save energy for the owners themselves. To do this, in zone 1 there will be the areas or things that most need to be visited throughout the day, such as the compost bin to throw away waste or the aromatic spiral to use those herbs in the kitchen.
As for the orientation, this should always be towards where the sun is positioned at noon (south in the northern hemisphere and facing north in the southern hemisphere). Therefore, it is important to protect yourself from the sun and wind by placing deciduous trees in front of the house and windbreaks in areas where the wind is coldest and most aggressive, normally the northern or northwest area in the northern hemisphere.
The materials are also considered. It is important, although not mandatory, to build a home with materials that have a low ecological impact and, if possible, can be found at hand. Stones from the place, cob or with superabe, wood from a nearby forest, etc. In this way the house will be a bioconstruction and will be built in the most ecological way possible.[34] Although many permaculturists choose to purchase a prefabricated small house (tiny house) or even to remodel an old shipping container.