FROM DESERT TO ABUNDANCE
When I first started working/playing with my land in northern New South Wales, fresh from my first workshop in Permaculture with Bill Mollison and Tony (Gehan) Gilfedder, I knew nothing, but was armed at least with the enthusiasm of the vision inspired by Bill’s approach, and the shining example of Tony and Lena’s transformation of a wasted ex-banana plantation into the sheer abundance of a sub-tropical polyculture paradise.
One of the first things that struck me was the simplicity of creating a very complex ecosystem. As Bill has said: “The productivity of a human-designed ecosystem is theoretically almost unlimited.” The greatest limitation is the imagination and capacity of people to recognise and implement naturally occurring processes: observation, deduction, and application.
Here is one shining example, which dramatically illustrates the potential:
Indonesia: Serangan – Turtle Island – is a small island detached from the mother island of Bali by only a channel of water. When the main port harbour of Bali was deepened, the resulting material of sand and coral was added to the smaller island to form an effective breakwater against the fury of the Indian Ocean in stormy weather. The resulting 600+ hectares of land only very thinly regenerated in the first 20 years.
This was the natural regrowth after 20 years – ‘soil’ like concrete
I was contacted to regenerate the barren wasteland of a few hundred hectares where virtually nothing had happened , apart from tufted low grasses sparsely scattered. The surface was like concrete, and although it seemed almost perfectly flat, I was convinced that vast amounts of water must run off every year on that impervious plain, to be lost in the ocean.
From my studies stimulated through Permaculture, I felt that there would be a fresh water lens under the surface. The island ‘peaked’ at barely 8 metres above sea level but a bore confirmed brackish sweet water at slightly over 6 metres depth.
We found brackish water (slightly salty) at 6.5 metres – just 1.5 metres above sea level
Having carefully patterned the area with a laser level, I had an excavator create rough (but perfectly horizontal) swales, overlapped to ensure that not a drop could be lost to the extent possible. After one evening of thunderstorms, this was the result:
After one thunderstorm event: soil and organic material deposited where there there seemed to be none.
Looking around, it’s easy to find vegetation that actually grows in such harsh conditions, even when it seems to be only sand and coral, as hard as concrete. There are always niches, such as small hollows in an almost flat landscape. In such places, seeds are deposited, wind-carried or rain-driven organic material collects; germination takes place with the species able to survive and grow, even in harsh conditions: a succession of regeneration begins.
Taking careful observation of all the species which grow in similar conditons, the selection of plants to use becomes obvious. Creating niches to encourage the growth accelerates the process rapidly. Groundcovers are vitally important, creating conditions of shade and lower temperatures to improve the conditions for the shrub and tree species, and providing new microclimates for a greater variety of species. Birds and insects and animals have food sources to encourage their arrival, and they bring more diversity and fertility as they feed and defecate.
The root action now opens up the soil further, so that more water is absorbed into the soil, carrying whatever dust and other organic material, creating soil quality which could not exist before. The whole desolate landscape begins to transform.
Wherever we plant one tree or shrub, we plant several companions, especially legumes and groundcover species, to add to the biomass and create an ‘oasis’ of abundance in the desert that surrounds. Now the action can really begin to explode.
Planting guilds – never solitary species
These guilds have ‘intelligence’; they ‘seek’ water, following it down as the top layers dry out, providing a fertile welcome for any other seeds, attracting wildlife which add to the fertily as well as depositing more seeds, greater diversity. These begin to join up with other ‘oases’. Regeneration gathers pace.
A forest begins from the desert
The need for planting rapidly decreases as the new species arrive to occupy ever-newer niches. Plant roots merge, and there is a sharing of nutrients, and chemical reactions which produce yet more relationships, with bacteria, funghi, enzymes, micro and macro-organisms all playing their role of enriching the world under the surface while above the surface the microclimate and biomass multipliesA geometric growth succession takes place as soil multiplies, becomes more sponge-like, moisture is held, the temperature stabilises, atmosphere more humid and welcoming.
The fresh water lens rose almost 3 metres through water conservation and planting
The water table has risen dramatically, by as much as three metres; roots have three metres less to seek a constant source of fresh water, and all the while, the increasing root matrix holds more water, more nutrients.
The whole ‘wasteland has become one vast network; a single organism. We should never plant single trees or shrubs. Group plantings become companions. Companions become oases. Oases join to become clusters, and the clusters unite to become a forest. Imagine this multiplied across the whole planet: the effect on the climate; the moderation of extremes; the storage water and nutrient; the availability of food, shelter, resources, activity, employment. Life quality for all beings.
The result, within six years.
This metamorphosis is in a monsoon tropical environment, with high humidity, hot and alternately very wet and very dry. Soil can be created, from nothing, at a very low energetic or financial cost. Biomass is the key to fertility creation and maintenance. The air we breathe is almost 80% nitrogen, one of the key building blocks for vegetal growth.
This transformation is very easily possible over a vast area of many millions of hectares of ‘wasteland’. Soil is not necessary, since it is biomass and niches for water and organic material to deposit and expand. We can very significantly accelerate the natural processes, simply by following the natural processes and examples which we find everywhere. Observation is the key, and sensitive deduction from the patterns which reveal themselves.
In more temperate climates, the dynamics are different: the soil quality is more important, soil creation slower, fertily creation is more important, through creating and providing composts, manures, fermentation processes to accelerate regeneration. However, the basic principles are same: Observe, deduce, respond, as active participants and accelerators of Nature’s abundance.
DAM/LAKE CONSTRUCTION PROCEDURE
You want to create a lake. This is a complex process well worth thinking through well in advance, so that you are properly prepared. This is a list for your consideration.
- Identify potential sites – prioritise and choose approximate site;
- Make soil test to determine suitability of site for good lake/dam construction:
- take several samples as deep as subsoil, possibly with soil sampling equipment;
- form a ring of the material large enough to form a bracelet
- put it in a bucket overnight
- take several samples as deep as subsoil, possibly with soil sampling equipment;
- If it is still an intact ring next morning, the material is likely to create a good dam
- local knowledge helps encourage/discourage likelihood of success!
- Remember that there are very good synthetic liners available, with a long warrantee period IF it is well installed!
- If there are size restrictions, use GoogleEarth to recognise dimensions in relationship to landscape and its characteristics;
- Create several fixed reference points for measurements; these could always be used for accurate mapping using triangulations, and to check accuracy of GoogleEarth;
- Peg it out and make adjustments according to visual perspective including aesthetic considerations;
- Establish where the water level would be; record it with a peg, marked to indicate it’s purpose as the water level (or how far below the surface of the soil is the water level);
- Check the horizontal points with vertical height using laser level (or you could use an A-frame or water level if you didn’t have a laser);
- Recognise what the differences in vertical heights in relationship to water level will be at different points around the perimeter of the lake;
- Peg out water level perimeter, marking existing soil level above projected water level (this will enable preplanning of landscaping to be done on completion of lake excavation;
- Determine where the spillway should be located, recognising where excess water will flow to, preferably into a swale system that ensures maximum retention and benefit of excess water.
- Both for level of spillway and level of dam wall height, be sure to take account of a layer of topsoil to cover all exposed soil for regeneration;
- Ensure that excess water will finally be discharged into existing water course;
- Select where topsoil can be placed near where it will be available to replace over subsoil used in dam wall construction and other earth exposed in construction;
- Take account of subsoil storage during excavation process for construction of dam wall;
- Be sure that double-handling of soils will not be necessary, and that access to subsoil will not be compromised or blocked during wall construction;
- Gently remove all topsoil from lake area, including area to be dam wall.
- Calculate inside wall no steeper than 2.5:1, and outside wall no steeper than 3:1, preferably shallower;
- Include at least 3 m wide flat area on top of dam wall;
- Place on pre-selected sites;
- Measure where will be spillway and carefully cut to final level, at least 60 cm below dam wall;
- Ensure that spillway is absolutely flat and wide with gently tapered walls to dam wall top and existing;
- Excavate all the subsoil to the depth of the first below water level; we have decided to create three terraces at 60cm, 120cm, and 2.7 – 3 m, with some lesser terracing within the first major terrace to provide diverse microclimates and depths for different water plant species;
- Cut key trench in along full length of dam wall, up to 1 m deep at deepest point and at least 1.3 m wide, reducing depth at wall limits according to land profile, being sure that wall will be fully integrated into subsoil for the entire length of the dam wall;
- Throughout all phases maintain constant reference pointS for measurement (eg; water level); note relative height of laser, so that adustments to other meaures (spillway, swale depth and height, wall height) can be maintained frequently and easily;
- Cut drainage pipe trench to a depth only slightly deeper than the pipe diameter (making sure that there is a downward slope), intersecting the key trench;
- Fit collars at regular intervals around the pipe sealing them(with silicon for PVC pipes, welded for steel) to disperse water which may move along pipe outside surface causing possible leakage;
- Compact soil around pipe – preferably by hand, although Thierry did not (we are dependent also on local experience, in the knowledge that the operator’s reputation is also on the line if the lake leaks excessively);
- Start building the wall, from the key trench up, compacting it thoroughly preferably every 20-30 cm, compacted;
- Inside wall is thoroughly compacted, but outside one is not heavily compacted;
- Excavate second terrace to required depth and continue raising wall, making sure that slope between terraces is gentle enough to allow easy movement, and prevent slope collapse;
- Continue building wall, removing stored subsoil in order that movement later to create swales from spillway runoff is not blocked or impeded;
- Continuously check that heights, slopes and compaction is correctly followed;
- To facilitate revegetation of steep inside dam wall, can cut a 15cm ledge just above waterline continuing up wall face so that topsoil can be stably placed for planting;
- If there is likely to be turbulence in water from wind impact, consider cutting to insert a stone ‘curtain’ in inside wall to slightly above water level, to prevent damage from wave action;
- Shape outside wall for best fit with existing landscape (this will determine if final integration appears harmonious or discordant with natural topography);
- Carry out any landscaping necessary to restore shoreline connection with lake, avoiding steep or high edges;
- Create steps for access in several points;
- Construct spillway swale, ensuring that sufficient wall freeboard is maintained to avoid risk of water overflow during extreme rains, taking into account wall height reduction as wall consolidates after construction;
- Precisely create spillway of swale to ensure back-fill of lake occurs without risking overflow of lake or swale walls, taking into account swale height lowering during consolidation;
- Reseed and replant immediately rain permits, if water is not available to maintain moisture:
- Steep-walled sections require particular attention:
- Hardy grasses for ‘matting’;
- Deep-rooted species for ‘anchoring’;
- Steep-walled sections require particular attention:
- Legumes for enriching soil for other species;
- Rye with alfalfa are a good mix for winter sowing;
- Can use matting:
- Pre-seed-impregnated jute/coconut, straw options;
- High-pressure hydro-sealing to spray seed mixed with sand, sawdust, dried horse/cow manure;
- Pegged jute or other matting to hold in place;
- Gentle slopes with multi-mix for insect attraction, anchoring, maximum cover (diverse species including leguminaceae, umbelliferae, graminaceae, brassicae families); select for hardiness, minimum maintenance
- Select for appropriate seasonal mixtures
- Let lake fill with water
- Add water from existing healthy lake(s) or dam(s) in the area, to inoculate your lake. As much as is practical, but even a few barrels full of water would be a big help. Quality is more important than quantity, within reason
- Only introduce fish after the lake has been full for a few months;
- If the lake is cloudy or unclear, adding gypsum will help to take suspended particles to the bottom; it will also help to reduce the acidity. And ideal pH is around 8 and more.
- If the lake leaks badly, you will have to line it with either :
- A high quality synthetic liner
- A layer of good clay at least 15 cm thick well compacted
- If there is sufficient soft organic material, and the pond is not too large, gleying is possible. This involves mashing a thick layer of the material, covering with an impermeable layer so that the mashed material ferments for a couple of weeks and creates a sealed pond when the impermeable layer is removed
- If the lake leaks only slightly:
- The lake may seal sufficiently with time
- Mix bentonite (very fine clay powder) in the top few centimetres of soil; the particles expand with water
- Sprinkle bentonite on the surface of the water (it will be drawn through the leaking area
- Penning a herd of cattle densely in the pond and leaving for some time may compact it sufficiently
- In a partially full pond, a stick of gelignite creates waves which compact the partially sealed soil together!
- Take care with introducing exotic or potentially invasive species:
- If they expand only through their roots, containing them is easy. Simply plant them in a suitable container under the water
- If the water is too deep, creating an artificial shelf will be sufficient
- Create a wetlands area immediately before a channel enters the lake; this can serve to isolate species, and also as a filter against excessive organic material or soil entering the lake and clouding it or negatively affecting the chemistry of the lake.
- Recognise that you have created many new microclimate niches in creating a lake through:
- Reflected light on the northern, western and eastern sides
- Raised warmth in winter, lowered temperatures in summer, especially where breezes pass across the water surface
- Increased humidity, both in the soil at water’s edge, and air around the whole lake generally
Each of these factors offers new opportunities for species which otherwise would not easily grow here.
DESIGNING FOR DISASTER
AThis is a new page that will be frequently upgraded to deal with specific relevant themes. Enjoy it, and ask questions, make criticism – or comment, or even complements thank you very much – and we’ll all get more out of it! Next up: WATER.
What a potential this has for our future nutrition, and for creating autonomous systems free of the tyranny of market forces, and with assurance that what we eat is what we think it is; viz, free of chemicals or grown under abusive or exploitive or unecological conditions.
Imagine a growing system that produces vegetables continuously on 2% of the water required by the same vegetables in ‘conventional’ irrigated soil systems! Plus the big bonus of fish as well, without needing to add to the surface area taken up by the vegetables. More to the point, as long as our ceiling is high enough (when growing indoors; otherwise the limits are only practical management ones), we can simply stack several layers of vegetables, put the fish on top, and use a ladder for the harvest!
We know that fresh water is considered the gold of the future. More accurate to say that it is actually the gold of the present, except we still aren’t prepared to pay the real price for it, like all other nature resources that humans exploit. There’s more benefit still too, from aquaponics, since when we have to clean out the fish tanks (likely to be necessary from time to time, since the water will gradually become too acidic for the more alkaline-loving fish), the water will be so rich that it can benefit our earth-planted vegetation.
DESIGNING FOR DISASTER
An aspect of good Permaculture design that must always be incorporated into our landuse is designing for disasters. Failure to design for extremes may lead to losing all our good work in one unconsidered event: fire, flood, drought, wind, storms, cold, heat. We can well say that Permaculture Design is Designing for Extremes since, no matter how ‘good’ our design may be for ‘normal’ conditions, it is how well it adapts to extremely strong, potential disasters that ultimately determines its sustainability and resilience. Of course Permaculture is much more than such a single theme, but failing to consider this one could put to waste all the other good work you have done, in one disastrous event.
It is not good enough to plan for averages. ‘Averages’ are becoming less and less ‘average’ as climate change effects increase. There are plenty of different considerations to be made as we enter the process of designing land. Disaster is one of them, and we must question the nature of any disaster possibilities.
Analysis of a Disaster
Design can’t be effective unless the designer has knowledge of the cause and conditions of any potential disasters. Specifically, can we avoid the impact of those disasters through good design? Start by asking these following questions:
* Cause of disaster – is it natural or man-made? Can we begin to reverse the cause?
* Frequency – how often does it occur? If it is once in 10,000 years, probably we need not put too much consideration into it. However, if it is likely to occur every few years – even every few decades – then we certainly should take it seriously.
* Duration – short or long-term?
* Speed of Onset – what is the warning period?
* Scope of Impact – is it concentrated or spread over a large area?
* Destructive Potential? – this can vary enormously.
* Predictability – does it follow a pattern? Seasonal, direction of source of disaster (wind, slope, situation/material supporting or limiting its impact).
* Controllability – are people helpless?
Fire, flood, cyclone, earthquake, tsunami, drought, landslide, famine, nuclear accident, epidemic, climate change, land degradation; all can be taken into account using these criteria.
Design…..General strategies to minimise the impact of disaster.
- Start with structure – apply permaculture principles of reducing risk.Create autonomous housing;have a small supplies of seed, store plants and water away from likely centre of disaster.Cave, underground room (against fire, nuclear or other pollution disaster, small mud house,
- If practical, ensure escape routes (creeks, fire trails, green belts)
- Small emergency garden away from disaster centre – perhaps just hardy food spp
- Windbreaks or berms to protect home and garden, or to change the direction (of fire, flood, hurricane, cyclone).
- Swales and berms to enhance water holding capabilities
- Ponds to enhance water holding capabilities
- A good pitched roof to shed snow (if you live in a cold/temperate climate) and rain.
- The use of heavy materials in construction such as mud/concrete/stone formed walls and metal roofs to reduce damage from wind; wood against earthquake; bamboo flexible and easily replaceable.
- Certain species of trees such as mulberries, oaks, willows, poplars, and maples are fire resistant. These can be planted densely with succulent groundcovers and shrubs to form a dense firebreak.
- Refuge island if you have a large dam
Types of Disaster
- ‘Insure’ against these by creating and being involved in community-building and maintaining. Choose your company; support people; be generous and fearless.
- Create LETS (Local Energy Trading System)system or similar
- Work together; work co-ops build more than houses and gardens; they build friendships and community.
A. Flood, Cyclone, Drought
– often can anticipate by weather statistics
eg; 1:100yr flood contour must have all structures above it. Allow for Greenhouse Effect. Have emergency garden out of flood reach.
Create solid berm (stone, earth very heavily planted with deep-rooted trees and shrubs
Plant trees and shrubs heavily beside all river banks to reduce energy of the floods, and encourage water to remain in river bed (if river is not limited to its course, river bed gradually silts up, spreading the flood waters instead of digging the river bed deeper). Regrass catchment areas to reduce silting up, and hence flooding
– do not enter floodwater on foot; use car, boats, or wait to be evacuated. Climb to roof
– don’t drink floodwater – often contaminated by sewage; carry bottles of bottled water
– don’t panic!
- these generally arrive from specific, predictable direction, and are anticipated by modern weather-forecasting, so we can design with a good degree of advanced information.
- houses need to be built with cyclone bolts, and as close to ground as possible, even underground. Or, use 45deg roof angle; cut stud into brace, and have it high pitched.
- Trees as windbreaks must be flexible – classically palms, bamboos, casuarinas, which absorb a lot of the force. Small-leafed and multi-stemmed shrubs with good root systems are priority plants
- Remain in shelter during and after passing of the ‘eye’. Every cyclone is dangerous, and must be treated as a real threat.
- Have a ‘famine’ garden in very sheltered area (eg; protected by wind arc of earth or vegetation to deflect wind)
Drought: will increase as climate change increases to bring more extreme conditions of wet/dry patterns
- normal part of many climates; never lose by greed or carelessness, supplies of seed or animals.
- Water must be kept clean and not fouled.
- All water recycled, preferably several times over (kitchen/bath water to toilet/plants
- all plants to be heavily mulched
- watering to be done under mulch layer
- no sprinkler watering; concentrate water with drip systems
- Animals: If drought is part of normal weather cycle, then pastures and feed can be ‘saved’, as silage. Animals need to be on a salt lick (urea?) to facilitate digestion of dry feed.
- 17-30 can be fed on 1ha permanent of cut and feed forage; free-range animals take 1-5ha in ave conditions (40-60 in desert and droughts). 2-4 draught and milkers average, so 6-8 farmersEssentials:
– shade for 15-30 animals. Floor should have mulch of fronds and hard straw from sugar cane, Pennisetum grasses, or palms
– up to 1ha of perrenial forage, cut daily and fed as one third to one half of the ration. Species include Honey locust, Acacia, arrowroot (Canna), comfrey and Pennisetum
– careful groundplan of multiple cross slope swales to catch and infiltrate run-off water in rains – this is critical
– herd animals are better to be grazed close for a short, intensive time, then moved closely; stall fed and controlled movements preserve land for higher fodder productivity
– all adjoining fields edged and wind-breaked with same spp, planted at 20-30m intervals in rows through all other crop, on bunds, along swales and ditches
– basic survival ha can be cut and managed in good years, but in drought all essential livestock penned in or near forage system for survival feeding. As no crops in drought, families tend on rotation
In drought, cattle can be fed on chopped dry stalk, small branches, straw, crushed cane, cardboard/paper provided they have access to lick of 10%(molases with urea added – 50-50). (eg; petrol drum in half-drum bath of molasses-urea. It is molasses-urea plus high cellulose cheap bulk food that enables cattle to breakdown some of the cellulose in wood and straw. Rest is provided from perennial forages, cut in succession and carried to pen; all manure and bedding is carried back to forage fields as mulch, preferably deposited in swales – mulch develops cool humus soils with good water capacity over time, and the forage plants thrive on this humus.
Dangers on range following rains:
-woody and ephemerals in drylands may concentrate toxic substances in new growth after rains, to protect against grazing for 4-6weeks -nitrates, oxalic acids, cyandes, alkaloids
SO, cattle shouldn’t be released to range, esp on single sp stand. Mature leaf generally not toxic; wide range of foods, some cut forage, mature leaf from trees. Same after browsing and burning
B. Nuclear ‘Accident’/Chemical Pollution
Who is going to live beyond such an event, and how?
- Protected water sources will be essential
- protected emergency garden also; a greenhouse becomes even more important as a architectural design component of the house.
- Recycling within the house structure of all nutrients
- Earthship design system of autonomous housing including indoor food production. Aquaponics important.
- Land Degradation/Famine
This of course is a longer term theme; usually the degradation (and such consequences as starvation and malnutrition) is slow moving and evolves over a longer time.
Dramatic exceptions to this are volcanoes (the flow of lava and lahar ash which totally blanket existing land), and tsunamis. The impact of both these can be significantly reduced though, be creating significant earth arc-berms in the sector from which such potential catastrophes would arrive (ocean-side for tsunamis; volcanic mountain-side for volcanoes) so that the arrival of lava/ash/wave would be greatly diverted away from the habitation or cropland. Of course this must be designed so that the reduction in damage risk to one land area does not become greater damage to the neighbouring or down-slope land!
Follow Permaculture strategies on water management, earthworks and vegetation strategies
Small areas can be made fire-safe. Non-oily spp, low litter, earth berms, close openings under house/eaves.
Principles for house protection against fire:
- Create defendable space
- Remove flammable objects from around the house
- Break up fuel continuity
- Carefully select, locate and maintain trees and shrubs
Factors in Fire Risk
a. Fuel – doubling of floor fuel – quadrupling of fire intensity. Pine needles burn faster than thicker matter
b. Mulches – dry mulches of annual grass, cereal crops, pasture burn very fast. Fibrous barks burn more than smooth bark
- Dry Fuel and Winds – increase risk of fired Topography – fire moves faster uphill
Design in Fire Control
1. Zone 1 garden around house, damp mulches, green mulches, irrigated, no open eaves, underhouse gaps to start fire.
2. Water – storage in irrigation/aquaculture ponds and tanks about the house. Plug and fill gutters, basin and baths. Have hoses inside.
3. Roads/Paths – leading away from principal direction fires come. Keep clear.
4. Orchards – excellent fire breaks, but watch citrus for oil
5. Animal yards – doors open to cool area
6. Radiant heat barriers – stone walls, mud walls, earthbanks, concrete, bricks, thick low hedges, white walls, fly screens
- Fire resistent plants – eucalypts regenerate BUT volatile oils explode, add to fire heat.No Proteacea, Myrtaceae, Rutaceae (all oil-rich species) in fire sector or near house
BUT fire-retardant – burn poorly, slow fire – wattles, succulent species (wandering jew), coprosma
8. Fire shelter – place where people can escape to if house burns -build of rock, mud, or inside hill, and whitewash it.
Understand aquaculture efficiency
Be able to design basic aquaculture system, understanding
principles for spp selection, stocking needs, nutrient req’mts
Same PC principles
as for other aspects of design
high oxygen is needed – SO greatest surface area is best; productivity of an aquaculture system is related to area rather than volume, since below two metres, very fish live because:
- less oxygen;
- less light
- less nutrient except in deposited soil and organic material
ie; can be mostly shallow, with deep spots for fish to escape in heat
An aquaculture pond can act as nutrient trap at bottom of system
Actually lose land, BUT Yield 4-20 times land system, because:
1 great diversity – wet soil trees on edge; permanent water levels critical; swamp plants ; emergents (bullrush); floating plants (water hyacinth); submergent plants
ii fish have greatest food-flesh ratio
iii temperature more consistent than surrounding land
Also: – aquatic env’mt can store more solar radiation than grasslands – convert this energy to fish flesh very efficient high protein.
– fastest growing landuse; best integrated with land systems – can yield between 250-1150kg protein/hectare
– water storage
– pest predator habitat – eg; frogs against mozzies
– microclimate and edge
– firebreak and control
SO,try to get 15% of land surface under water, at least during wet season!!!
Water from aquaculture pond is nutrient-rich, so any water used to irrigate plants is super-charged with a ‘soup’ of many nutrients valuable to plants. Win-win!
Why so efficient?
– cold-blooded , so don’t use up energy controlling body temp.
– fish weight supported by water, so more food energy for growth
– can be grown on waste, such as animal residues
– fish farming can be carried out on marginal land, making it productive
- ponds can add another use to existing facilities, such as irrigation dams;
- since aquaculture functions best in slightly alkaline water (7-9), if there is not a regular through-flow of water (in the case of a mostly rain-fed pond for example) acidity may increase especially if animals such as ducks or pigs are used to add fertility to the water as a symbiotic animal-fish system. This can reduce the productivity of the pond through high pH and over nutrification which deprives the water of oxygen.
- In such cases, the pond can be occasionally drained, planted with green manure which absorbs the high-nutrient level of the pond soil, and this can be used as fertilizer, complementing agriculture and increasing overall food prod’n
YIELDS; in terms of protein 4.05ha water > product than 80.9ha grazing
- nutrient water from fish and animals very rich (see above for problems associated with acidity; it has excellent pH level – best used for tree crops as may be too much N for vegetables
The city of Kalkutta in India produces over 20,000kg of fish PER DAY from its aquaculture. Not to mention the amount of other food produced. The system works – theoretically at least – on a series of lakes, each one functioning to treat the pollutants, reducing it to the point where it is healthy enough for edible fish. The first lakes produce biomass which grows biomass for reforestation, while extracting the heaviest pollutants. The next ones also produce vast amounts of biomass, plus fish and other aquatic species are introduced; this process continues, each system extracting more pollutants until the point that fishes which can only live in relatively clean water, survive. Thereafter productive edible aquaculture systems provide the 20,000 kg/day of edible fish plus aquatic edible plants. It’s all win from a pollution source to an abundance of many dimensions.
Factors in Setting up aquaculture ponds
* pH 7-9. Anything under 6.5 won’t be very productive. pH 7.5-8.0 is optimum, but will change at different times of year
- depth at least 2m in middle so fish can escape from heat. >2m is not valuable from a harvest perspective. Ideal temp 18-25degC.
* clear water. Hold large silver coin 450mm under water; if clearly seen, clear enough for fish. Turbidity reduces sun’s penetration and thus algal growth. Small amount of obscurity can inhibit predators. Gypsum will clear muddiness and help balance pH. 560kg/ha added in small quantities is effective in clearing murkiness
* available food required – grow your own food. New dam can be inocculated by taking a bucket of water from old dam to breed up plants and micro-organisms. Algal feeders need heavy manuring and algae needs sun. Grass eaters need water plants along the edges. Taro is an excellent feed with weeds in between. Mulch edge of new dam immediately to encourage edge plants and reduce erosion and run-off. if within 30deg of the Equator, mallee prawn does well. Suspend nets vertically in water to grow algae.
– some as runoff from agricultural land
– from leaves, other deitrus, insects falling from fruit & veg.
- manure from water birds and fish
- manure, scraps added directly; animals can be penned over pond
- pigeon coop standing in pond against fox attack
- floating chicken house;
- pig or cow house flowing into fish pond
– nutrient levels must be monitored, balanced by extra fish etc
– feeding sludge from bio-gas unit
– wild animals – bat nesting-box with rungs and bat shit in first
– bottom sludge should be slightly basic, but often acidic from manure etc – to correct, add lime , or periodically drain and grow high nutrient crop, leaving residue as nutrients in bottom of pond, and refill
* existing vegetation must be assisted to attract insects or drop feed into the dam. It also provides an immediate habitat for micro-organisms.
* size, number of fish and carrying capacity is related to surface area, NOT to depth of water or total volume. The ratio is of Size of Surface: Edge length.
- water level stability and water loss; top up if required. Oxygen levels are one of the most important factors. A reticulation system (running water, esp from height) or flow forms can help.
What are the main factors affecting your yields? Can you suggest ways to improve on this? Brainstorm.
Factors affecting yield
* Pond shape and shape
- longer the edge and greater the shallow area, more food available ; ie; crennelated edge, NOT straight sides or circular
- different levels are important to provide range of habitats; large fish naturally move to deeper water and deep water ensures region of lower temps during summer months. Shallow water can carry weed growth which offers protection to small fish, and is source of large quantities of food, providing habitat for water fowl, and producing food crops such as water chestnuts, taro, and arrowhead ie; polyculture.
In case of lake losing water through evaporation or leakage, be sure to have a deep section lined with an impermeable membrane to hold water.
- allows for proper management practices, cleaning of the pond, removal of sludge for use as fertilizer, and complete harvesting of the fish if this is reqruired.* Screen
– at overflow essential to allow for drainage. Bottom slopes to outlet
– are should be managed in complementary ways, should be grassed to reduce muddiness of water, no sprays to be used and stock should be excluded.
– need to be provided for fish – tyres, terra-cotta pipes
* Pond Bottom
– very important in biology of the body of water; a good bottom is able to quickly recycle nutrients and make them available – if poor, bottom decay is slow. Gravel, clay and sand bottoms can be improved by the addition of organic matter such as stable manure, sewerage sludge or by sowing a green manure crop before filling dam with water.
Criteria for selection of plant and animal species
* Pond Size and shape– There is surface area, edge and depth which is suitable for certain species and affects their stocking rate amd available food supply.
– need to consider water temp, and max/min temps and overall geographic areas eg; inland, coast, mountains.
* Available Sunlight
– plant large species on the north (Nth hem) side of dam, since large trees on the south will obscure winter sunlight when it can be most important
– summer temp, wind speed & rainfall will interact. Water levels may need to be topped up
* Environmental Impact
– whether species can escape and become pests and also the interactions between species and symbiosis. Something needs to be known of the food chains in the water, and their inter-relationships. The more suited to their new habitats, the greater the growth rate.
– summer breezes will re-oxygenate the water – appropriate wind machines can be used to oxygenate water also. Perhaps plant wind funnels
* Water Quality
– amount of sediment, watershed and pollution(DDT 100 years in mud) – agricultural runoff -> increased weed growth and algal blooms
– 30m forest on catchment
* Before Stocking
– new dam should be allowed at least 3 months to settle and to allow establishment of a good food supply
Fish Stocking Rates
DO NOT stock low; the fish grow very big and are hard to catch. With very high stocking rates, the fish stay small
100 fish/surface acre without extra feeding
feed via pond fertilization – manures
When stocking ensure that there are no other fish, or eels. Eels can be trapped from empty dams by shaking in Derris Dust which asphyxiates them. After two weeks, the effects of the Derris Dust is gone.
Some fish like to breed under things or on floating rafts, logs and clay pipes
Shrimps like to hide in little things. They will dig holes in dam walls. They love living in beer cans (non-rust aluminium) suspended from a raft. Shrimps will eat worms. Big frogs eat prawns.
Freshwater mussels; can be grown on ropes and can filter 200 gallons of water per day (cleansing like kidneys). They also deposit phosphate.
Goldfish eat mosquitoes.
Different fish occupy different depths of water.
- Insectivorous fish occupy the surface water
- Herbivorous fish occupy the pond edges where there are grasses and other edge aquatic plants. Chinese say: “if you feed one grass carp well, you feed three other fish”.
- Fish which eat predominantly faeces occupy a medium depth
- Mud dwellers extract nutrient from deposited soil (eg; catfish – flesh tends to be ‘gritty’.
- So, ponds can be divided with suspended nets at appropriate depths toseparate predator fish from others. Rafts with suspended netting can also be installed. Predator fish only get the little fish that swim by. Fish can also be separated completely in cages:
fish cage: exclusion for safety from predators; easy harvest; multi species in small space
- In this way, many different species can occupy the same pond any problems arising of carnivorous fish over-eating other species and dominating.
- In marshes and wetlands make sinks to grow fish and prawns. This can also be done in mangroves.
Can have a main pond with small ponds around it.
Management of Fish
* Harvest smaller/medium sized fish (large for breeding
* Use traps,nets or line to catch fish
Lack of Oxygen occurs in hot weather,may occur after rain when organic matter such as animal manures, vegetable matter has been washed into dam. Decomposition of OM uses up oxygen. Sign of oxygen deficiency are dead fish or fish coming to surface gasping for air. Oxygen may be replaced by circulating water or, pumping it up and spraying back onto surface of water. IT CAN BE AVOIDED BY MAINTAINING A BETTER BALANCE IN THE FIRST PLACE.
A windmill – paddle floating on dam.
Air rippling on water will work.
Ducks swimming on the water.
Predators – Cormorants. Fish are quick to learn about safe retreats, not metal pipes or chicken wire as they release chemicals into the water. Abundance of forage fish or crustaceans (shrimps, goldfish) will ease predation pressures on dam fish.
Undesirable Fish – eels are problem (eat fingerlings -> reduce chances of establishing fish in dams). Removed using lights and baits of fresh meat.
Weeds – water hyacinth, but very good food supplement for cattle and pigs
– roots provide habitat for organisms eaten by fish etc
– good compost, mulch
– stems for basket weaving
* Never introduce water weeds unless sure of identity and characteristics
THE ESSENCE OF AQUATIC POLYCULTURE – AQUACULTURE
Each species of fish feeds on specific micro-organisms
Each species can’t use all available food eg; edge species (eg;mulberry) provides fruit, eaten in water by fish, on land by ducks, ducks manure the water, utilized as food by fish/ micro-organisms which feed fish; mulberry also feeds insects drop in water and eaten by fish, as is frass (excrement or other refuse of boring lavae). Leaves which fall in water are also eaten, especially by shrimp.
When food is not fully utilized, imbalances can develop with a drop in oxygen levels.
Email Post ChangesGood farm combinations are:
Fish and Pigs, Ducks, Domestic Waste, Agricultural Waste eg; rice, Industrial Waste eg; abattoirs, sugarbeet processing, Worm Farming
Fish wastes when there is only one species, can build to levels that foul water and inhibit growth
Limits overcome by stocking several species – match diff levels of food
When up to 6 spp fish, and waterfowl, are stocked, the predators of fish take no more than 15% of fish
Herbiverous fish perform a special function; Chinese say: “if you feed one grass carp well, you feed three other fish”. Grass carp consume massive quantities ofpartially digested materials, which directly feed bottom-feeding fish ie; common carp, and stimulate production in other parts of the food web. Grass carp can grow as much as 3-4kg/annum. (The Chinese use Mulberries particularly since they feed duck and fish on fruit and the leaves feed shrimp and grass carp).
Production can be increased three times with pig manure/sun/carp. Then water plants growth increased with nutrients from increased fish stocking & growth.
A SUCCESSFUL POLYCULTURE HAS A MIXTURE OF FISH, CRAYFISH, PLANTS, MOLLUSCS, WATER FOWL AND EDGE PLANTS
SEEPAGE areas can be used for mints, bamboo, and trees such as willows, pecans and poplars
There needs to be gradual shelving from ‘dry’ land to 1.2m
Taro->Chinese waterchestnut->Duck potato->Bullrush->Waterlily->Lotus->Indian Chesnut Sagitarria Cumbungi
– perennials and non-cultivated spp help consolidate and stabilize edge, and support insects -> pond and support livestock -> pond manure
– large evergreen to north, deciduous to south
– emergent plants at edge attract insects – add to pond floor: bananas, papaya, pineapple, mango, lychee, feijoa, blueberries, mulberries(add silkworms too), pecans, hazelnuts
Shrubs and Herbs: comfrey, sweet potato, lavenders, lemongrass, fragrant plants, millet, passionfruit, kiwifruit, tea tree
chinese water chestnut (Eleocharis)} 1sq.m. from 1 corm (8-9mths growth high pH – divide when harvesting
indian water chestnut (Trapa) } diff spp.
taro – Colocasia (shallow water or moist soil – good understorey; corm is carbohydrate, also young leaves and stems – steamed, well cooked to destroy calcium oxynate crystals, fermented into poi
kangong – water spinach (Ipomea) convulvulous, leaves very nutritious, and good livestock feed
bullrushes – whole plant is edible; roots eaten like potato
water cress Rorippa aquatica (daily picked with flow)
lotus (water lilies – roots, stems in salad, seeds like popcorn; grows to depth of 2.5m. Embed in ball of soft clay with shot poking out; drop in water.
arrowhead – leaves or root (arrowroot) – ground root to paste, dry for powder as thickener
Fodder grasses: comfrey, kikuyu, wandering jew, sugar cane
Fibre plants: bamboo, papyrus, NZ flax
Island vegetation: chose for controlling rampancy and as nests for birds
cane grass, pampas grass
* Keep plan and diary recording all tree/vegetation info – source, variety, neighbours etc
* Remember: after a few years, dam can be drained and terraces of sleepers etc put in place – excellent planting area for almost any crops
POLYCULTURE: combination of appropriate plant, water and fish spp for max yield, min space –
top – herbivores feed on algae
bottom – dwellers on mud
middle level – fish
Different order of ponds
different size ponds – different products
1. Tyre Pond – good in Zone 1
tyre pond for microclimate & diversity
HOW? 1. Large tractor tyre (NOT radial steel mesh!), with one side-wall cut out, possibly with a serrated edge kitchen knife (hard work!), keeping blade wet, and exerting cutting pressure as you pull up. For radial tyre, use angle grinder with blade, or by drilling holes and cutting with bolt cutters. NB: Tyre not necessary!
2. Dig hole to depth required, slightly larger than tyre diameter. Spread 3cm layer of sand.
3. Lay large sheet of heavy duty plastic – enough for double layer wrapped generously around bottom and sides of tyre, and to line inside. Place tyre on top and plastic wrap. Spread 5cm layer of sand on bottom.
- Soil and composted material in tyre rim for deep water plants, with shallower ones in pots, placed on bricks to required level. Fill slowly
waterlily, taro, water chestnut (Guppies, goldfish against mozzies) Urban Situations
– water tubs, tyreponds, baths
– low maintenance, don’t need watering, weeding or mulching. Attracts birds , raises humidity around pond, good for subtropical plants such as papaya, provides habitat for insect predators (frogs,lizards). Plants are very ornamental.
Siting – needs full sun and low point looks more natural
Requirements – scavengers help establish natural balance, fish and water snails clean up rotting vegetation and algae, goldfish eat mosquito larvae and other insects. Plants and fish prefer mature water so do not empty pond unnecessarily and top up gradually.
Fertilizer – can be small amounts of compost or manure. Water lilies serve practical function by keeping oxygen in water by trapping it under lilypads.
Planting – containers are advantageous because water is clearer, it allows for easy harvesting of plants, easy repotting and division. The pond is easily cleaned. Use a clayey soil with compost or well rotted manure.
2. 4-5m across
– greater range of aquatic plants – eg; with steps
– fresh water prawns
– weed-eating fish (carp, catfish)
– household scraps, compost, manure
- some microclimate effect
3. 5-8m across
– all above, greater variety of fish (polyculture)
4. 1/4 acre
– semi commercial – commercial
– prawns/fish with ducks (feed ducks, manure feeds fish)
– ducks/fish forage themselves, ducks on plants, and emerging vegetation
– freshwater mussels
– need to hold in freshwater > 2hours to clean mud
– good filter system
– excrete phosphates into mud (periodic fertilizer)
– shells can be ground for liming pond, or fed to poultry as Calcium supplement
– in smaller pond, can cause pollution (by dying)
– dragon flies are indicator of good water health
5. Large ponds
– eel (world shortage) and fish rearing – hold eels from muddy ponds for 3 days before harvesting (bones high Calcium source)
NB: eels if stocked too high can destroy fish AND can cross country to get to stocked pond
SO may be better to raise in completely separated tanks, netted against escape!
– prawns farming (10lbs prawns cf. 1lb fish)
– eat leaves
– don’t like overcrowding – like to 2m depth
– need specific water temp (16-25deg) over 32deg will kill BUT can hibernate
BUT shrimps can cause dam leaks with rocky dam wall
AND eels eat ducks
yabbies like cloudy water’ (so ducks good)
many predators (birds, snakes etc) so need refuges
– sensitive to water pollution
6. Very large ponds
– edge vegetation for mulch
- fish and eels and prawns as wild harvest
Where to place pond(s)?
- Depends on where the water source is;
- relatively low maintenance after initial setting-up
- can be multi-functional depending on size (fish/irrigation/recreation/micro-climate influence)
- depends on size and shape of land
- high on the land offers greater potential for gravity-feed irrigation to gardens, fruiting trees, field crops when necessary
- low on land is last opportunity to trap and store soil and nutrients before it otherwise would flow out of the land.
Best is series of ponds – good for building up of nutrient – 4-7% increase in protein from pond compared with stream water
different system each pond (see example above of Kalkutta system for treating polluted water), but an suggestion is:
1st – reeds, ducks, geese (manure fertilizes water, but too high for fish)
nutrients trapped in plants – people, green mulch, fish protein
Azolla (water weed) – floating water fermentation – nitrogen fertilizer overflows to Pond 2
– high protein content – food and green manure, biogas digester, dried and stored as food
Duck weed doesn’t fert nitrogen, high biomass (40tonnes/ha/yr)
1st overflows to 2nd pond
polyculture of plant-eating fish – duckweed and azolla controlled by feeding
duck, geese, mussels, freshwater clams
2nd overflows to 3rd
polyculture including carniverous fish
Each pond should have capacity drain it empty, either by syphon system with pipe, or lock-pipe system.
dam construction – above
If it can’t be topped up, then have floating raft and place plants in it. If raft is too high, can be weighed down with baskets of water lilies. Just add soil until raft floats at desired level, OR in case of raft with barrel flotation support, water can be added or subtracted to appropriate level for plants grown in raft. (See Diagrams Dam Construction Profile, and Drainage Pipe through Dam Wall, and Raft Island)
raft island; excellent strategy for adding diversity, refuge, edge, beauty
use sweet flavours to attract fruit flies, use honey and sugar 60% of fish food is insects. Can use a brick boiled in liver to attract blowfly family.
ADD one thing at a time to water, and observe what happens.
water-logged and shallow ponds /temp water
– edge between water and land systems
– very diverse 2-3000 useful marsh spp
– imp. as wildlife
– birds for insect control
– flood storage areas – absorb excess runoff, slowly release
– very important bee forage source
– used in treatment of human and industrial waste
– secondary effluent -> swamps -> nutrients and filter
– heavy metal (lead, mercury) temporarily trapped
– production of mulch and fertilizer
– high moisture content
– constant temp and high nutrients -> huge bio-mass
– equiv to seaweed as fertilizer
– grazing and stockfood (pigs, geese cattle)
– levels of limiting amino acid are lower though protein as high
– higher in calcium, potassium, magnesium, than land
– geese grazing with berry growing
– pigs originally forest and marshland foragers
– cattle forage during dry times, provided mud-pugging isn’t serious
Coppicing spp close planted (0.5m sq)
If land is small, and there is a large percentage of swamplands, this can be transformed into a chinampa system, in which the swampy land is trenched, with the material resulting from the deepening placed between each trench to form a mound which can be planted.
Aquaponics is another dimension of aquaculture especially appropriate for small-scale fish raising, with the added benefit of creating a closed-loop of nutrient cycle, with the fish providing the nutrient (through their faeces) for vegetable cultivation.
Of course a far more aesthetically pleasing system can be put together if space is not so important, but this is certainly a great example of stacking in practise!
Aquaponics is a valuable consideration as a recycling potential. These are small and large scale systems, in salt and in fresh water. They can be very simple, such as in the rice-fish systems of South East Asia, or more sophisticated and available as complete systems, at a price of course. Broadly speaking they consist of a series of components in which the water is filtered at various levels and recycled.
How it works (in brief):
- Fish are raised in a tank using a feed of commercial fish food (or by experimenting with various combinations of, for example, flaked grain and manure).
- The over flow of the fish tank (this water is highly enriched by fish faeces) flows through a filter removing solids unusable by plants;
- the ammonium in the faeces may be converted to nitrates by nitrification bacteria in this filter, before it;
- Flows into a tank or tanks in which a medium of substrate (sand, gravel, if not actually soil) supports the plants to be grown;
- the water at the bottom of the system is filtered again and pumped back to the fish tanks.
Since water is a significant factor, this both recycles the precious water, AND reduces water needed to grow the same vegetables outside in the soil. Not a bad result of win-wins, particularly in such a situation of water limitations.
Rearing tank: the tanks for raising and feeding the fish;
- Settling basin: a unit for catching uneaten food and detached biofilms, and for settling out fine particulates;
- Biofilter: a place where the nitrification bacteria can grow and convertammonia into nitrates, which are usable by the plants;
Hydroponics subsystem: the portion of the system where plants are grown by absorbing excess nutrients from the water;
- Sump: the lowest point in the system where the water flows to and from which it is pumped back to the rearing tanks.
Worms are amazing! All we need to do, is give them what they need! Then they do the rest. Simple as that. So,
What do they need, or not need?
- Like any compost system, the worm compost system needs to be shaded
- the material in which they live needs to be moist, but NOT wet. A rough test is to take a handful of the organic material you are feeding them , or the material which the worms have already eaten and processed. Squeeze it strongly and if you get more than a drop or so of moisture dripping out, then it’s too wet. The worms can easily drown! Too dry doesn’t work either, but it’s no rocket science to know what that moisture level is.
- Best to avoid, or put minimum citrus or onion in it. Also minimum cooked material
- NO meat – worms are strictly vegetarian!
- They don’t need to be disturbed excessively. Just leave them and they will do their stuff incredibly well. They will:
- not go where it is too wet or dry
- not eat food they don’t like
- will aerate the material beautifully, so you need to do nothing except add their food
You don’t need to be too fussy about what kind of worms you use. They’re all doing what they do best, and I feel better using local worms any way, rather than introducing another exotic species unnecessarily. Give them what they need, and they will thrive beyond your imagination!
Start with 200 mature worms in a well created wormculture system
Average reproduction 30 per worm/month (very conservative for good conditions)
1 month 200X30 6000
6 months 180,000
12 “ 5,400,000
18 “ 162,000,000
24 “ 4,860,000,000
This is approximately 5 thousand million worms after 2 years, from 200!!