Permaculture Designers Manual
CHAPTER 9 –
EARTH WORKING AND EARTH RESOURCES IN PERMACULTURE
Section 9.8 –
Moving the Earth in Permaculture
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People have always moved earth:
To reach water in dry river beds;
to mine pigments for their decoration;
to excavate food as bulbs, grubs or fungi and
to bury their feces or their dead.
The archetypal tool is the digging stick, which gets food of greater variety and more nutrition than the spear. The basic hoe, rake and shovel exist today in most cultures.
Hand tools have moved most of the earth we see today shaped into mountain rice terraces.
There are some very useful and cooperative ways to dig, effective in making miles of low irrigation banks or unloading gravels. The two-person shovel is useful here, one digging in, the other pulling over in a see-saw motion. (Figure 9.26)
Try it, and be surprised at how rhythm and cooperation will move mountains.
Sing a little tune to pass the time and get the rhythm:
Down among the dead men
Let me lie…. etc.
However, the exigencies of education have meant that designers and architects have seldom been personally involved in earth moving.
A brief description and nomenclature of machinery and modern tools is not only needed but essential to earth design, given that when we move earth we should do so for permanent and beneficial ends.
We can revolutionize eroded and arid landscapes by commencing the process with tools and consolidating it with life forms, especially trees.
EARTHMOVING MACHINES
Just as there are hand tools suited to particular ways of digging, so there are large machines suited to special landscape tasks. Any of these can be supplanted by human labor where it is plentiful.
The basic earth-moving attachments are these:
BLADE (can be mounted on almost any vehicle, or towed); includes “V” blades or delvers.
BUCKET (for lifting and loading loose material); narrow and toothed for hard ground, or of special shapes for drains.
BUCKET CHAIN (for foundations, pipelines, narrow deep ditches, underwater dredging).
SCOOP (can be horse or bullock-drawn, or articulated on a hydraulic or telescopic arm).
RIPPER (for breaking up compacted soils); usually towed or rear-mounted on tractors.
DELVER (for one-pass drains; often mounted on a grader or towed on a frame behind a bulldozer).
SPINNER (rear-mounted on a special tractor); a fast-revolving disc of about 2-3 m diameter with peripheral buckets.
BORERS AND DRILLS (holes, fences, explosives, pipes, wells, bores, and the like)
JET PUMPS (to pump out si.lt and sand in wet places).
(Figure 9.27)
As well as these, there are explosives, which are of special use in marshes and swamps, and some specialized tools for rock and swamp work, for mines and for massive tunneling.
Our concern here, however, is for the common tools of landscaping and water storage or water channeling. Each has appropriate uses, although most can do something of what the others do.
To take them one at a time:
The Blade Machines
The blade earthmovers are the machines for leveling and benching or terracing and ideally they should be able to lift (and drop), angle, and tilt.
They can be mounted forward (bulldozer), in the centre (grader) or at the rear (wheel tractors, for leveling).
Tilted, the blade can make shallow V ditches, or put crowns on roads. Angled, it spills earth to one side as steering walls or makes long shallow drains.
Blades are ideal for leveling house sites, for terraces, for benches on hillside, for side-cutting roads, and for pushing up earth walls.
Even a small tractor (17-25hp), patiently worked, can make very large dams and terraces at less fuel cost (but greater time cost) than a bulldozer, while large bulldozers are the most economical of time. They can work difficult, steep, or stony sites and move very large objects such as boulders.
The bulldozer is a blade machine, mainly for pushing and planing earth. It is of greatest use in roading and for dams. It is an excellent machine to put up, roll solid, and spread earth, to dig large shallow holes, move small hills and to bench.
The blade TILTS for road crown slopes and ANGLES for casting aside windrows of earth; it also LIFTS to spread and release loads and DROPS to delve out drains and ditches.
Angled blades are used in long runs to cast earth out continuously to one side (called side casting).
Tilted blades are used to cut channels or to bench slopes and lift is used mainly for piling up or leveling loads. Blades are normally forward mounted for sight and control reasons, but on that special road machine, the GRADER, the blade is mid-mounted to give even spreading and on small farm or wheeled tractors is often rear mounted.
Some small blades rotate about their axis (180° swivel). The grader can be used to make long drains, of shallow angle; these are miscalled spoon drains, but are effectively more angled than spooned in section.
Thus, for all normal bench work, a bulldozer is useful, and for long flat road or leveling runs a grader is better. A SCRAPER is a large, self-filling bucket or land dredge which can both fill and empty itself to plane off or dig out large areas.
All large machines can now be laser guided to accurately level and grade fields at a pre-set slope. Lasers can also automatically work the hydraulics to lift and drop earth, but land forming is mainly restricted to large flattish irrigation areas or civil works and is normally contracted out to specialists with large machines.
The Four- Way Bucket
This machine (sometimes called a drott) combines all four motions of lift, dig, push, and pull, and is a bridging and universal machine between blade and bucket types.
It is usually fitted to a bulldozer body, and is an excellent landscaping machine. It differs from some bucket machines in that it cannot swivel the blade separately from the body of the machine, nor can any of the above blade machines. It is sometimes called a clamshell bucket because it can close on loads of earth or delicately pick up large stones, shave a curve in embankments or fill a truck with soil.
A small wheeled machine, the Bobcat, is an excellent finishing tool or used alone for light work or for making swales in Zones 2 and 3.
Buckets (Figure 9.28) Types of Cuts (Figure 9.29)
Buckets
These can be simple and fixed or complex and swiveled; the former are often fitted to wheeled tractors as LOADING BUCKETS of great use in quarries, nurseries and anywhere loose material needs to be picked up and loaded to trucks at heights up to 4m. They can lift and tip, but not swivel sideways.
A very useful tool for drains and as a tool in marshes is the SWIVEL or SCOOP BUCKET machines, which can scoop out, swivel around and deposit loads.
Some of these machines can dig wells to 9m (30 feet) using hydraulic extension arms and all can dig sharp-edged pits or drains for special uses.
They can normally reach out 6-10m (20-32 feet), and (standing on dry land) take silt from canals or ponds.
To reach out much further, there are two tools, the DRAGLINE, a giant fishing rod or crane which casts out a loose or tractor-tethered bucket dredge up to 18 to 24m (60 to 80 feet) and hauls it in full and a two-tractor dragline, where one tractor hauls an endless rope with a bucket across greater distances than the crane dragline.
SCOOPS are often used behind horses or oxen to excavate small ponds or clean out ponds of silt. Unless fitted with a rear spill door or chain tipper, they are very hard work to tip by hand alone and tire one out quickly.
A special tool of great efficiency in flatlands and on low slopes is the SPINNER, a large wheel with small peripheral buckets spun at high speed, which throw out the earth as small clods a considerable distance.
They are much used in Holland to drain polders and are the most economical and speedy machines for flatland (shallow) drains.
The spinner is one tool that distributes the spoil as small clods as it travels; there are therefore no banks beside spinner drains.
A special TRENCH DIGGER is a chain-bucket system which continuously digs narrow trenches for pipe-laying or to insulate foundations. Commercially, it is called a “Ditch-Witch” or “Trench-Wench”.
Augers and Drills
These are hand or mechanical post-hole diggers suited to most soils. Other uses are in tree and tuber planting, although care must be taken not to compact soils or to create water-filled holes in clay.
The prime use is for posts and fencing at present. Augers have a limited lift and are used to (normally) 2m (6 feet) or so depth, whereas drills which have extension tubes can operate to great depths.
The borings are removed by liquid flushing or are simply compacted and tube-lined. Purely hydraulic drills work to great depths and bores and hydraulic nozzles are often combined.
Some of the largest vertical and horizontal earth holes (mines and quanats) were once hand-cut by primitive tools and wells to 30m or even 60m (100-200 feet) are still hand dug throughout the world.
Special large-bore augers to 1m (3 feet) are used at mines and most carry extensions to make a 2m wide shaft.
Very large pneumatic blowers are crane mounted to remove loose materials and are often locally made as at the Coober Pedy opal mines in Australia.
Large-bore drills there are called Caldwells after the inventor and are used for underground housing, excavation, shafts and tunnels up to 1.5 m (5 feet) diameter.
Explosives
Explosives are of most use to assist auger holes in hard ground, to make holes in otherwise unstable ground such as marshes or to loosen rock in quarries.
With the advent of the swamp tractor, marsh blasting is less common, but the basic ease and effectiveness of explosives should not be overlooked where they can solve some otherwise intractable problems.
Nitroglycerine (cellulose treated with acid, in glycerin, absorbed into wood dust or clay earths) as gelignite, dynamite or plastique is an inexpensive way to solve some earth-moving problems.
Even cheaper is the mix of ammonium nitrate fertilizer and dieseline known in the trade as “chickenshit” (nitrates have from ancient times been gathered from manures, around the soil of toilet pits, or extracted by washing and evaporation from guano).
Old “recipe” books give dozens of reliable recipes for cheap explosives, and even custard powder, flour or face-powder will blow a room apart, as will the fumes from ether or domestic gases. I once worked as a scientific glassblower and managed to remove all doors and windows from my room by allowing ether to evaporate from a bottle.
Earlier, as a baker in my father’s business, I created some spectacular flashes using plain flour near open flames.
Today, we must take a course to obtain a “powder monkey” certificate in order to set our own explosives or we should hire skilled people. Yesterday (pre terrorist), we simply made the stuff up and let it go, with unpredictable results and often too much effect.
Hydraulic Jets
There are several ways in which the quiet but powerful actions of water jets assist our endeavors.
Firstly, a simple jet nozzle fixed inside a pipe and connected to a garden tap may well serve to drill a water bore (a water spear) in a few minutes or hours in sands, gravels or deep soils.
Secondly, an old hose-pipe fastened to a sharpened pile or post and connected to a hose will serve to sink jetty pilings in silt or sand in very little time.
A jet pump (commercially available) will remove silt, sediment, mulch and even large gravel from a dam and deposit these behind a retaining wall as rich terrace soil, while the water flows back to the dam.
Lastly, jets fired at loose sediment washes down gravels, sands and soils for mining as terraces or to remove land slips from roads and fields. Quite precise control of such action is achievable.
Hydraulic nozzles, “drills” and jet pumps are all made by industry to serve these purposes and also to steer deep drills in boreholes to specific locations underground when tapping oil, thermal energy or for venting mines and caves.
Again (as with explosives) it is enough to know the range of uses, keep them in mind and to get good advice if the need arises.
Inadvertent jet drilling has a powerful pulling action and jet pumps with their motors; rafts or platforms can be dragged below water or across the ground if one is left unattended.
Occasionally, a garden hose will bury itself in sandy soils in this way and so be lost.
Powerful air jets now take gravels from mines in much the same way and a whole series of turbines and powerful pistons operate from pressure applied by water, air, or oil (the science is applied hydraulics or pneumatics).
A jet plus a cutting drill will cool the area and remove waste in one operation.
Finishing
Rakes and rollers are the tools for finishing excavated earth; the former to fine level, the later to compact.
Compaction is only necessary where traffic or water retention is intended, but when it is necessary may need to be accompanied by water sprinkling in dry conditions.
Care must be taken to compact only 15-30cm (6-12 inches) of soil thoroughly at a time. Even very heavy machines can seldom compact depths greater than 38cm (15 inches) and impact or hand compaction is effective for less than half that depth.
It is necessary to strictly adhere to this careful compaction for dams and house foundations. Modern compacting machines often vibrate, using a pneumatic or mechanical eccentric weight to impact and shake soil as it is compacted.
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