永续耕种设计原理| 每个元素发挥多种作用

Each Element Performs Many Functions

The second Permaculture Design principle is 'Each Element Performs Many Functions’.

To maximise the efficiency of a design, every element (component) is selected and located with the intention that it serves as many functions as possible.

We can only do this when we fully recognise all the properties of an element, and when this element is a plant or animal, we must have a thorough knowledge of this organism. This includes it needs, outputs. attributes, the optimum conditions and the range which it can tolerate, and so forth.

One way to do this is to perform a 'functional analysis’ to identify an element’s needs, products, behaviours and intrinsic characteristics.

When looking at plants, we need to identify aspects such as:

1. Form – lifestyle (is the plant annual or perennial, is the tree deciduous or evergreen) and shape (is it a ground cover, shrub, tree or vine, and how tall does it grow)
2. Tolerances – light requirements (shade, partial shade or full sun), habitat (dry, moist or wet, low or high elevation), climate (arid, temperate, subtropical or tropical), soil type tolerance (sandy, silty, clay, loamy, peaty, or chalky soil types), and soil pH (acid, neutral or alkaline soil)
3. Uses – edible, medicinal, animal forage, soil improvement (nitrogen fixing, cover crop, green manure), site protection (erosion control, living fence, windbreak)

If we look at a Willow tree for example, the functional analysis would be as follows:

1. Form – deciduous tree, weeping habit, up to 30m high, fast growing and short lived, propagates easily from cuttings.
2. Tolerances – Requires full sun, grows best in moist soil that is well-draining, often found beside streams and in damp areas. It is salt tolerant, and tolerant of a wide variety of soils and pH.
3. Uses:

   Source of Medicine – The bark of white willow contains salicin, which is a chemical similar to aspirin, used for the treatment of pain, headache, and inflammatory conditions.

   Source of Material for Construction and Manufacturing – the wood is used to make furniture, cricket bats, tool handles, wood veneers, and toys. It is used in wood turning. Willows provide wicker for weaving of wicker baskets and for making fish traps. The wood can also be used as a source of fibre for making rope, string and paper. Charcoal used by artists is exclusively made from willow.

   Source of Energy – Willow is grown for biomass, a renewable energy source which reduces the need for fossil fuels and petroleum products.

Ecological/Environmental Uses – Willows have many beneficial environmental uses. They can be used in the following areas:

> Riparian buffers – Natural barriers that prevent chemicals from entering streams, ponds, and lakes.

> Phytoremediation – Willows clean up toxins from contaminated sites.

> Wastewater management (biofiltration) – Willows filter contaminants from wastewater, and can be used in ecological wastewater treatment systems.

> Environmental protection and preservation – Willows are often used for land reclamation, streambank stabilisation (bioengineering), slope stabilisation, soil erosion control, shelterbelt and windbreak construction, soil building, and soil reclamation.

> Environmental reconstruction – Willows are used for constructing wetlands and wildlife habitat.

> Gardening – Willows are used for in the construction of hedges, “living fences” and other living garden structures and general landscaping

> Living snowfences – Strategically planted willows trap drifting snow.

> Farming – Willows can used by farmers as an animal forage to feed their stock.

Horticultural Uses – Willow bark contains natural plant growth hormones which can be used for rooting new cuttings.

Now, if we take the above functional analysis, we can design a practical application of the 'Each Element Performs Many Functions’ principle .

Here we have a steep slope on a creek bank adjoining a farm, with run-off and possible contaminants coning in off the farm. The steep banks are vulnerable to erosion from the fast flowing run-off of rainwater uphill.

Placing a willows allows us to stabilise the banks with the tree’s intricate root net and prevent soil erosion. The roots enter into the water where they create a home and shelter for fish, increasing the fish population. Any contaminants or nutrient run-off from the farm are captured by the willow, preventing them from entering and polluting the waterway. The roots also filter the water in the waterway, clearing and cleaning it. The dense canopy provides a natural evaporative cooling which creates a protective microclimate. It also creates an effective windbreak. This creates a buffer from the harsh elements which supports the creation of a local wildlife habitat which can support a greater amount of flora and fauna than a bare bank. The sheep on the farm are provided with a nice shady sheltered spot, and they also have a source of forage in the overhanging willow branches. As we can see, the willow provides many functions, so one element performs many functions.

A more urban example might also be appropriate here, something you’re more likely to see in a regular suburban back yard.

This is what it looks like in real life, when first built:

Here’s the same system, fully grown:

Once again, all of the elements serve multiple purposes.

The grapevine:

1. Shields the two 8′x4′ vegetable beds behind it from the harsh west evening sun and strong winds.
2. Provides a microclimate for the strawberry bed underneath,
3. The autumn leaves that fall from the grapevine will provide mulch for the strawberries.
4. Produces grapes and vine leaves which are both edible!

The strawberries:

1. Create a living mulch ground cover which conserves moisture for the grapevine, limiting water loss by evaporation from the soil in summer.
2. Produce strawberries, which are edible

It actually gets much complicated than that in my design. When we introduce a herbaceous layer, (we end up with three layers vertically, this is another Permaculture principle, that of Stacking) we add more element with multiple uses and they all act together in synergy.

To one side of the grape vine trellis, I have planted Citronella Geranium, and to the other side, Hyssop. Both these plants are good companion plants to grapevines, and this particular geranium is insect repellent and works a treat if you rub it all over exposed skin to prevent mosquito bites. Just the thing for late evening simmer gardening! The hyssop is also a medicinal herb for lung aliments, used since early European herbalism.

Furthermore, the trellis itself is an element, which serves multiple uses. When the grapevine is dormant and has lost all it’s leaves, the bare trellis can be used to support climbing peas, which therefore creates a system of succession planting also (which, incidentally, is another Permaculture design principle)!

So, in essence, in order to produce functional and effective designs, you must thoroughly understand:

1. The nature of the elements you are designing with, and
2. The range of elements you can possibly use in a design situation,
3. The reason and justification for using the elements you have from the range of choices available.

Designing Permaculture food production systems is all about designing with plants first and foremost, so if you don’t know your plants intimately, then I recommend you do so as soon as possible. Permaculture garden design presupposes a high level of competency in horticultural skills, and the only way you’ll gain these is by working with plants over a period of time till you really understand plants. To be frank, your designs will only be ever as good as your understanding of the plants you use and the range of plants know about. Plants are living entities, not 'design features’ like the landscaper’s pergolas, water features and paved paths.

Remember, you are designing with Life itself, and how can you even begin to design living ecosystems with Life itself if you don’t understand the nature of that Life.

With an understanding, or even better, a real connection to Nature, the natural harmony and efficiency of Nature will be ultimately reflected in your designs!