11 Designing for rural properties
Planning is required for any sustainable farming development. The development of whole farm plans and the integration of all components on the farm further illustrates the importance of functional design.
The design of shelterbelts, fodder lock-up areas, water harvesting drains and woodlot areas must contain information about the maintenance and management of the system.
Economical analysis of the monetary outlay and income of farming and land management strategies has shown that putting in tree belts, building dams and undertaking earthworks for drainage and so on, can all have a high benefit-to-cost ratio. Essentially, this means that these strategies can make more money than they cost the farmer.
Not all benefits are financial in nature. Landcare, conservation and land management strategies will help improve the quality of the environment and also make the farm look pleasing - aesthetics are important to humans. Improving the quality of waterways, conserving and restoring natural wetlands, wildlife habitats and bush areas, and increasing the recreational value of land all benefit the community.
Farmers and land owners must consider what they will do to ensure the best return for money invested for land improvement work. When money is not freely available for all farm planning strategies, then some prioritising of all of the options should occur. Setting priorities helps the land owner to work towards realistic goals and the slow, ongoing implementation of the design.
An integrated whole farm plan allows all appropriate conservation and development practices to be blended together into a single system. The outcome will be good land management practice, as waterlogged areas dry out, dry areas get water, salinity problems are addressed and soil quality improves.
It might also mean that waterlogged areas are better used by planting wetland plants, and dryland species are used to maximise the potential of dry areas. Whole farm plans often have the following characteristics:
• paddocks are divided into homogeneous land units by soil type, natural topographical features, vegetation types, or water drainage areas.
• each land unit is managed and developed after examination of the potential stock carrying capacity, crop yield, amount of degradation and erosion, and soil fertility.
• the impact of developments and improvements such as roads, revegetation, water harvesting strategies and crop and pasture changes are considered in the light of the whole farm - in an integrated, holistic way.
• farm management strategies must incorporate sustainable practices, such as maximising nutrient recycling, minimising energy and resource use, maintaining land productivity, preserving natural ecosystems and increasing species diversity, as well as making sure that the farm is profitable.
The successful implementation of a whole farm plan is a long-term process. It literally takes many years before financial benefits to crops, pastures and animals result from tree planting and other sustainable land practices.
However, even though land owners make substantial capital investments on improvements to the soil, fences, fodder areas and water catchments, the value of the farm land increases and other benefits to the environment follow.
Most farmers view replanting and revegetation initiatives in terms of economic return. They need to be convinced that shelterbelts, regeneration of native forest areas and replanting of riparian (stream or river bank) areas will add value to their property, make the use of the land more sustainable and give a potential income in the long term.
Income from woodlots and specialised timber may take ten years or more. Even fodder tree species have to be fenced from stock for two to three years before cutting or grazing is allowed. Farmers should be encouraged to become foresters and to replant trees in degraded areas and near remnant vegetation patches. Furthermore, conservation must be seen as good business.
Economic viability must be equated to ecological stability. For example, on small and broad-acre properties the practice of minimum tillage should be investigated.
Nature doesn’t plough and turn the soil, and nor should we. You may need to break up compacted ground, either by using a chisel plough or, in some cases, ripping to plant tree belts.
Ripping along the contour also increases water absorption by the soil. This can be an effective strategy as this technique is cheaper than building swales.
Severe winds reduce food production. The most damaging winds are hot and dry or those coming from offshore laden with salt. These types of winds increase the transpiration and desiccation of the plant. Cold winds during winter will also adversely affect many subtropical species.
Strong winds can do physical or mechanical damage and the ferocity of severe winds needs to be tempered. Many food producing trees such as kiwifruit, macadamia nut and bananas are easily damaged by wind, with food yield reduced.
Windbreaks should be positioned to counter the effects of severe winds, whether they are prevailing or not. Prevailing winds are those blowing most often from a particular direction.
In some places your windbreak tree belt may have to be placed on the eastern side of the house, in other areas the western side. In other places, the prevailing winds could be south-westerly or north-easterly.
The wind direction of prevailing winds in winter will differ from those in summer, and cooling, summer afternoon (ocean) breezes are often in opposite directions to night-time (land) breezes.
You might like to re-read Chapter 3, which deals with sector planning, to have a better understanding of where windbreaks are placed and how the energies that move through a system are directed and controlled.
Figure 11.1 Tree shape gives some indication of the direction of prevailing winds.
Land and sea breezes occur because of the uneven heating and cooling rates of land (soil) and water. During the day, the land heats up faster than the sea. Hot air rises above the land and is replaced by a cool sea breeze which usually blows in the afternoon. At night, the land cools faster than the sea and cold air from the land flows towards the ocean.
Sometimes, wind blowing across the land heats up and it is not uncommon to experience hot, dry land breezes early in the morning. Water tends to heat up and cool down slower than the land.
There are several terms which have the same meaning and hence are interchangeable. For example, shelterbelts are essentially windbreaks. However, we sometimes use shelterbelts to describe rows of trees surrounding agricultural land while windbreaks may refer to those trees protecting buildings, orchards and garden areas. Shelterbelts and windbreaks are planted in a direction which is about 90º (right angles) to the prevailing winds. Shelterbelts, as the name implies, are often arranged so that stock can find shelter and refuge in them, especially when giving birth and during storms.
Windbreaks protect the soil, preventing it from drying out and minimising the loss of topsoil by wind erosion. Greater production occurs in areas protected by windbreaks. Trees make the best windbreaks. Solid fences should never be built as they can be pushed over by the force of strong winds and they cause turbulence.
As a general rule of thumb the area protected by a tree windbreak system is about twenty times the height of the trees. In Figure 11.5, if the trees were 5 metres high, the distance that is protected on the leeward side is about 100 metres.
Figure 11.2 Land and sea breezes.
Figure 11.3 Shelterbelts are windbreaks that provide protection of stock.
Windbreaks should be a minimum of three rows, but preferably five rows in some circumstances. Five row windbreaks can be used for paddock fence lines within the property. These give protection to the paddocks on both sides of the windbreak system because wind speed is reduced and winds are ramped over them.
Trees also reduce the amount of wind passing through the area. At least half of the wind may still pass through, but at a much slower, less damaging speed. Trees further reduce wind erosion by trapping sand and silt.
Figure 11.4 Windbreaks are used to deflect wind upwards.
Figure 11.5 Tree windbreaks offer protection for 15 - 20 times their height.
Figure 11.6 Poorly designed windbreaks can intensify the problem. Shrubs and trees should have foliage to ground level.
Large trees which are slow-growing, such as oaks and carobs, should be planted in the middle rows (of a five-row set) and the fast-growing (and nitrogen-fixing) trees, such as wattles, tagasaste and casuarina, are planted on the outside. These offer protection while the more productive and often commercially-viable species are growing.
Like all permaculture elements, windbreaks should also serve several other functions. For example, windbreak trees can also be used for bee forage, sources of mulch and firewood, screens for noise, absorbers of pollution, shelterbelts for stock and suntraps for climate modification. Species which can serve as fodder and windbreak include acacia, tagasaste, carob, oaks and leucaena.
Well-designed windbreaks can also slow a fire to one-tenth of its speed. Windbreak trees, which are used as natural firebreaks as well, should have high moisture contents, low levels of flammable resin and oils, and should not shed leaves and branches.
Whenever any planting occurs, the sequence of shrubs and trees should follow nature’s pathway. Pioneer trees need to be planted first on denuded and degraded land.
Once these are established the larger climax species can be planted. Remember that the pioneer species such as acacias, casuarinas (or holly and brambles in colder climates) are good windbreak species and protect the climax species such as oaks, nuts, beech or carobs.
Figure 11.7 Windbreaks should contain several rows of trees.
Figure 11.8 Trees have to be staggered so that both wind speed and wind penetration is reduced.
Stock need shelter from cold winds as many will die in extreme conditions lasting several days. Shelterbelts of trees provide refuge as well as fodder during these lean times.
Figure 11.9 Wind must be able to penetrate some of the tree belt, or turbulence will occur.
Stock production decreases both during extreme cold and extreme heat. In fact, shelter is crucial to stock productivity, as open pastures will decrease milk, wool and meat production. The placement of these belts of trees, fences for stock yards and water supplies are crucial to any property containing stock.
Figure 11.10 Windbreaks should be curved so that wind is deflected as well as slowed. Banna grass (Pennisetum spp.) or clumping bamboos are useful windbreaks. Here a windbreak also acts as a suntrap.
Shelterbelts can also be productive in other ways - as sources of firewood, honey, mulch, building timber and edible crops. For example, chestnuts for humans and oaks for stock. Fast growing, potentially commercial timber species include paulownia (Paulownia tomentosa), blackwood (Acacia melanoxylon), silky oak (Grevillea robusta) and oaks (Quercus spp.) generally. Fast-growing nursery, stock feed and nitrogen-fixing trees include wattles (Acacia spp.), tagasaste (Chamaecytisus palmensis) and Albizia lophantha.
Figure 11.11 Nurse trees such as tagasaste or . wattles are used to protect wind- and sun-sensitive plants such as macadamia nut trees. Nurse trees can be continually pruned as the protected tree grows.
The arrangement of tree belts with arable land in-between, which is used to grow some sort of crop, is called alley cropping or hedgerow intercropping. Even though arable land is lost in the planting of these tree belts, the total production of the land increases and it is a worthy system to adopt.
Alley cropping, which is also known as agroforestry or forest farming, is growing trees, usually as tree belts, in conjunction with agricultural crops or pasture and domestic grazing animals, or both.
The other issue for permaculturalists is that we should be advocating the use of perennial pasture crops rather than annual pastures. Perennial pasture plants include herbs such as comfrey and dandelion, and fodder shrubs and trees such as Coprosma, willows, poplars, tagasaste and medics. Finally, larger nut and berry trees, such as oaks, leuceana and carobs, should be used as they drop pods or nuts with high carbohydrate and/or protein content during the lean autumn or fall periods.
Alley cropping practices in the paddock should follow the contour as much as possible (again to harvest water to supplement their needs). Even small pockets of trees would effectively improve pastures and reduce erosion. For some windbreaks on a slope, place swales every 10 m or more to capture water to provide additional watering of the trees. The higher slope areas tend to dry out first so you should rotate stock from high areas downwards.
Tree belts have the added advantages of: stock shelter and shade; microclimate changes so that crop areas are more productive; greater animal and bird life on the farm; source of nectar and pollen for bees; and source of firewood, construction poles, fencing posts and timber. All of this means, in turn, greater stock carrying capacity and greater opportunity to diversify farm income, by developing aquaculture in the dams, honey from bee hives and timber for sale.
On large agricultural areas, shelterbelts may be spaced about 20x the height of the tallest tree. This corresponds to the amount of protection that this shelterbelt offers.
Planting trees close together ensures canopy closure which, in turn, minimises wind infiltration. However, light is restricted from penetrating to the ground layer and few plants will grow as under storey. Under storey shrubs increase the ecological diversity and stability, and they are important in the tree belt system. Good design of shelterbelts will allow thinning and pruning without affecting their effectiveness against wind.
There is no magical number for the percentage of farmland which should be planted or replanted with trees. Even at 15% tree cover, the loss of production of pasture is more than compensated by increased crop production and potential income from tree-based enterprises.
Furthermore, try to design zone 5 areas so that they are linked to natural bushland, remnant bush areas and wildlife corridors. Consider planting rare and endangered species from these areas - especially on steep slopes greater than 15 to 18º - as one way you can contribute to their survival.
The replanting of indigenous tree species in areas which were once forested but are now depleted, such as sparse bushland and agricultural areas, is called “reforestation”. Afforestation is planting trees in areas which are devoid of trees, such as desert areas. Even so, many of these desert areas were once forested, but are no longer because of climatic change and human intervention.
Figure 11.12 Trees planted close together (1 m apart) tend to be tall and narrow while those of the same species planted further apart tend to become more bushy and widespread.
To get plants established, some preparation and care should be undertaken. Direct seeding is a cheap method of tree planting, and provided the seeds have been pre-treated, such as pelletising the seed or scarifying the seed coat, success should follow.
Small seed can be mixed with sand before spreading. The land owner is advised to initially proceed on a small scale, until a working system is developed and established.
Overgrazing a weed-infested area by stock, before planting, may give new seedlings a greater chance of survival. Generally, seed planting is more successful than tubestock planting, as germinated seeds send down long roots in search of water, whereas roots are often pruned (air or physical) in tubestock pots and do not re-establish quickly in the ground.
Poor weed control is perhaps the greatest hindrance to plant establishment.
Each farm animal has its own special requirements and its own special functions. Large animals such as horses and cows require large amounts of water and feed, are difficult to control and pen, are less efficient at converting plant material into animal protein and have a low reproductive potential.
As you can imagine, most small animals, such as sheep, guinea pigs and poultry, are much the opposite.
The selection of the number and type of animals that are placed in the system depends on factors such as:
• climate and environment conditions. Some breeds of sheep, for example, prefer dry climates, while others survive on poor hill sites or in fertile lowland areas.
• size of property. For example, you may only have enough land to carry one cow but ten sheep.
• breeding habits. Some animals produce large litters (pigs) while others only one or two offspring (cows, sheep). You may need to assess the potential damage that could be caused by domestic stock which escape and become feral, including their effects on native animals and plant populations.
• forage and fodder requirements. Chickens require a minimum of about 200 g a day, while sheep consume 1 to 2 kg and cows usually greater than 5 to 6 kg.
• stocking rate. For example, only one cow for every ten acres, one sheep an acre and so on. This depends on the carrying capacity of the land.
• purpose. You might choose stock for meat, wool, milk or manure. You may want an animal to keep the weeds down in the paddock. If you want land cleared, and shrubs, trees and weeds removed, then get pigs.
Pigs can be contained by electric fencing, as shown in figure 11.13. A simple electric line is all you need. The pigs will “learn” quickly and test the line periodically - or push one of their mates into the electric fence to see if it is still on!
• personal preference. Some people prefer particular animals and not others. Since you will be looking after the animals, take time to consider your opinion.
• husbandry needs. Animals have particular needs. For example, sheep may need dipping and drenching (for lice and parasitic worms respectively), while cattle might have to be treated for mastitis, ringworm or warbles (lumps under the skin caused by the grubs of warble flies).
In planning for stock, make sure you consider both the land capability and the sex ratio. For example, one sheep per acre, one cow per ten acres, one ram for fifty ewes and one rooster for 10 hens. Stocking levels need to be low enough to allow plant regrowth. Some characteristics and requirements for particular animals are listed in the tables that follow.
Stock lock-up areas are a good way to provide feed all year round. In Figure 11.14 stock are maintained in pen A for a few weeks and then moved into pen B. This set-up and rotation can be repeated all along the farm boundary (if serving as a windbreak as well), or wherever stock are kept. Stock should only be locked up in the fodder pens for a short time, then moved on.
Figure 11.13 Pigs can be contained by electric fencing.
| Animal | Size | Financial commitment | Feeding habit | Reproductive fecundity |
| Horse | Large | large | grazer | low |
| Cow | large | large | grazer | low |
| Sheep | medium | small | grazer | low |
| Rabbits | small | small | grazer | high |
| Pigs | medium | medium | scratcher | high |
| Chickens | small | small | scratcher | high |
| Goat | medium | medium | browser | low |
Table 11.1 Some Characteristics of animals.
| Animal | Uses, notes | Manure as fertilizer | Special requirements |
| Horse | draft animal | Fair | Shelter |
| Cow | milk producer, manure | poor, slow release | consistent good quality feed for milk |
| Sheep | wool or meat | Fair | Shearing |
| Rabbits | meat, fur | very good | shelter, protection from predators |
| Pigs | meat, omnivorous diet | Poor | Shelter |
| Chickens | eggs, meat | Good | shelter, protection from predators |
| Goat | milk producer, need strong, secure fencing | Good | consistent good quality feed for milk |
Table 11.2 More characteristics of selected animals.
Note:
1. Animal manure for use as fertiliser is judged by the percentage of nitrogen and phosphorus.
2. Grazers mow the grasses to near ground level. Browsers prefer new leafy shoots and buds of shrubs and trees. They eat above the ground.
It is important to only allow the stock a short stay in each enclosure, as plants that are too badly eaten and pruned may never recover.
Different types of stock can be rotated through the same area, one after another. For example, cattle could be contained first. They will chop off higher limbs, some of which will fall on the ground or hang lower. After a week or two (depending on the number of plants and animals in the pen area) they can be moved on and replaced by sheep which will browse the broken and lower-hanging branches.
Stock must be rotated through grazing areas. Plants that are overgrazed react by producing and secreting toxins to deter browsers. Moving stock on also allows trees and shrubs to recover and produce new shoots.
Figure 11.14 An example of a stock lock-up forage system.
A moveable electric fence is used in this intensive strip-grazing paddock. Fodder species such as wattles (e.g. Acacia saligna, A. longifolia), tagasaste (Chaemocytisus palmensis), albizia (Albizia lophantha), honey locust (Gleditsia triacanthos) and leucaena (Leucaena leucocephala) are grown, usually in rows about five metres apart so that machinery can be driven between them.
An alternative system combines fodder with a windbreak strip. Fodder trees (as mentioned above) and shrubs such as tree medic (Medicago arborea) are planted as a windbreak along the length of a paddock. Stock can be directed into the fodder strip, which is usually used as an occasional feeding lot, especially during the “autumn feed gap”, or they can forage along the fence line at all times.
Figure 11.15 Stock start at the top and are directed downhill as the paddock dries up or tree damage is imminent.
If electric or conventional fencing is too difficult or too costly, or other factors limit this type of system, you can simply cut plant material and feed the stock at your will. Prune trees at waist to shoulder height. If you let the trees get too big, stock won’t be able to reach and you’ll need a ladder to prune them yourself.
Commercial slashers and cutters are now available, so trimming the plants occasionally by machine may be practical, if you can hire or find a contractor. Tree cutters are expensive to buy, but for large farms, having your own machine may be necessary.
Figure 11.16 Suckering or running varieties of poplar, wattle and bamboo can be used as a fodder provision strategy for stock. As long as the parent tree is not devastated or eaten, the tree will survive even if the suckering growth parts are eaten to the ground. Established trees may not even need fencing.
Figure 11.17 Coppicing of willow species produces many wands or canes which are used for craft work or stock fodder.
Many trees can be coppiced. This means that you can cut the tree at stump height and it will re-grow. The cut foliage can be used as fodder, building timber or firewood. Poplars and willows are well-known coppicing trees.