Permaculture Designers Manual
CHAPTER 9 –
EARTH WORKING AND EARTH RESOURCES IN PERMACULTURE
Section 9.1 –
Introduction to Earth Working and Earth Resources in Permaculture
Moving of the earth brings harms and fears
Men reckon what it did and meant
But trepidation of the spheres
Though greater far, Is Innocent
Few people today muck around in earth, and when on international flights, I often find I have the only decently dirty fingernails.
For the soil scientist, soil has endless classifications; to engineers, it is a material; to potters, their basic resource; and to housekeepers, footprints on the floor or part of the eternal dust.
However we look upon earth, we will all return to it and help create the soils our ancestors made, ruined or form part of, climate, vegetation animals and soil are intimately connected and each will have influences on the other.
It is a great subject, like that of water, and this module will concentrate more on its use in structural design than on its uses as a growing medium.
People, and other animal species, have mined soils and earth deposits for specific earth resources since their inception; examples are animal migrations to salt licks and specific dusting sites in which birds and mammals roll or bath to rid themselves of parasites.
Soils rich in iron oxides have long been mixed with acorn meals to fix the bitter tannins as insoluble ferric tannates (“black” breads), or to supply missing elements in the diet.
There are several clays (illite, smeltite, kaolin, ferrous oxide “red” clays) traditionally used by tribal and modem peoples to absorb poisons (from Solanum spp., yams), to reduce diarrhea and digestive upsets, or to relieve feelings of nausea (kaolin clay).
Although little work has been carried out on this factor, we should record all uses when specific clays are so used and how they are combined with specific food to reduce or eliminate poisonous or unpalatable toxins from foods.
Some earths may be eaten to supply trace elements, as clay and clay-salt licks are commonly visited by deer, kangaroo, cattle and antelope.
Earth-eating (geophagy) is a widespread and seemingly natural habit of children and tribal people. As well as clays, the white, mineral-rich ash of trees is widely used as a food dip at campfires by Australian Aborigines.
Cooking food in clay is prevalent throughout the world.
Earth working for agriculture and monuments has existed for at least 17,000 years. Mineral smelting, pottery and peat or coal mining for fuels increased the scope of earthworks and this was quickly followed by the development of large machinery intended to remove vast amounts of ores and fuels for modern Industry, which built quickly from 1800 on, so that the last 200 years of our existence has seen the greatest development of earth working and mining.
The common use of self-transporting machines really dates from the post-war years (1947 and on), following the wartime development of tracked tanks, earth scoops used for airfield construction and large pneumatic tires for this type of equipment.
While civil engineers have to some extent kept pace with these developments, neither the public at large nor those in architectural or agricultural fields have fully realized the potential of earth working machines in the modern sense.
Our power to move the earth with modem machines is now almost unlimited; we can, if we wish, raise new hills or plane off existing ones and create or obliterate minor landscape features.
Small earthworks are so immediately effective, cheap and permanent that it continually amazes me that people will suffer local drought, sea winds, noise, erosion or even flooding without spending the few hundred dollars on a well-built and planted earth bank that would solve the problem.
They will build expensive tank stands or towers rather than a cheap hill and suffer death by storm and fire rather than make a very safe earth shelter for their families (it serves, as an outdoor cellar at other times).
Earthworks are necessary and ethical where they:
Reduce our need for energy (underground housing in deserts);
Diversify our landscape for food production (fish culture ponds);
Permanently rehabilitate damage (contour banks, interceptor banks);
Save materials (house site design); or
Enable better land use or help re-vegetate the earth.
As with all techniques, it profits us to make as many uses of earth shaping as we can; it is shameful to see quarries, mines and roads serving a single purpose and usually left as a sterile system, when they could be shaped or planted to assist landscape diversity.
A whole set of skilled and well-tried waste or soil reclamation strategies has developed as methods of stabilizing devastated landscapes, both for natural instability and the carelessness of engineers.
An excellent handbook for those involved in such painstaking work and one covering many climates and areas is that of Dr. Hugo Schiechtl (Bioengineering for Land Reclamation and Conservation, University of Alberta Press, 1980). I cannot too highly recommend this book for would be earthmovers.
Earth can be moved for productive reasons, many of them classifiable as landscape restitution:
To Create shelter; to assist with foundations and to make areas level for floors;
To terrace hill slopes for stable paddy crop, wet terraces or gardens;
To raise banks or to dig ditches as defenses against flood, fire, attack or wandering vegetation-eaters;
To drain or fill areas (to direct water flow or run-off;
To create access roads to those places we commonly visit;
To get at earth materials (ochres, clays, minerals, fuels);
To make holes for any number of reasons and of greatly varying sizes from fence-posts to dams, wells to deeply drilled bores;
To create special storages and enlarge living space (cellars and caves);
To stop erosive forces carrying off soils (soil conditioning and erosion control);
To prevent noise pollution (embankments); and
To permit recharge of groundwater’s (swales and ripping).
We also move the earth to play and to plant. For all these reasons, we have devised hand-held and mechanical diggers, ditchers, augers, drills, blades, buckets, shoes, rakes, ploughs, rippers, delvers, scoops, earth planes, loaders, rock-cutters, draglines, excavators, and dredgers.
We also move earth with explosives, hydraulic jets and as an unintentional result of erosive processes generally.
Erosion has itself been used to build soil terraces on lower slopes in more than one culture, but it is debatable if the terrace idea was not as a result of attempts to stop erosion before the idea of using erosion to create terraces later developed.
Until the Second World War, earth was moved by sheer numbers of people, by hand or horse and car, or by a few people working with wheelbarrows or baskets over a long period.
All this has changed. Why put up thousands of mud bricks when a machine can compact a 6-8 m thick wall immune to flood, fire, and earthquake in a few hours?
Or labor long hours, over a hole, when we can blast a fence-post in hard shale bases for a few cents?
In this module, I will not attempt to deal with large, complex or precise civil works, those necessary for sewage layouts, the landscape excavations for large buildings or large dams, ports or aerodromes.
I will instead limit myself to those on-farm, private, useful, relatively small, and rehabilitative or sustainable earth-moving systems that an individual might employ to shelter a house or to control water in a productive landscape.