Agriculture
Until 2,000 years ago, the Middle-East was the main provider of food for the ancient world. Although we falsely believe that agricultural science is a recent development, archaeological studies have proved that much may be learned from the pre-historic farmers.
What Went Wrong?
Almost certainly agriculture failed in the Middle-East for several reasons, namely climate change; conversion of an agricultural economy to a nomadic economy with flocks of grazing animals following Moorish invasions; destruction of public utilities, and instability of government.
The Israelis have re-introduced many of the sucessful pre-historic agricultural techniques. Their skills should be applied to other arid areas, as a part of a programme to reverse global warming. In South Australia, SAARDI has a long history of experience in dry-land farming.
We should be careful to avoid the effects of over-grazing, e.g. by regulating the size of domestic herds, and by the control of feral grazing animals, such as rabbits, goats, donkeys, camels and horses.
Arid Area Farming
Where economically possible, the following techniques should be adopted to conserve water supplies.
Surplus water should be stored in suitable underground acquifers or, as potable water or for livestock watering, in covered cisterns or reservoirs. This prevents contamination by pollutants or loss by evaporation.
Uncontrolled run-off of water and resultant soil erosion should be minimised by terracing, interruption of watercourses, contour ploughing, minimum tillage and mulching. Wetlands should be established on flood plains.
Leguminous plants should be included in crop rotation cycles. After harvesting the crop, the plants should be ploughed-in as mulch.
Water for irrigation should be distributed in closed channels or pipes, and delivered to plants by drip feeds.
Saline waste water should not be returned to watercourses - it should be concentrated in evaporation ponds, or (preferably) be de-salinated. The recovered salt has value.
Quite saline waste water may be used to irrigate salt-tolerant trees or shrubs.
Tree Plantations
Tree plantations should be established wherever possible, in order to sequester cabon dioxide, reduce erosion, provide a habitat for beneficial insects and birds, and provide shelter for animal stocks. (In 2008, an ABC Landline programme featured a pastoralist who has increased treestocks on his previously-cleared property to as much as 35% by area, with greatly-reduced stock feed, increased wool production, and reduced stock mortality following shearing.)
The most suitable species of plants should be chosen for each climate area, bearing in mind the future anticipated effects of global warming. Plants which bear a valuable crop, such as some Australian native species e.g. macadamia nut trees, are to be preferred. Palm oil is a valuable source of bio-diesel. Australian sandalwood is being farmed profitably in Western Australia.
When street trees were planted at Woomera many years ago, a length of terra cotta pipe was buried vertically, alongside each tree. The tree roots were watered at intervals through the pipes. This proved to be very succesful and saved water.
In southern Australia, plantations of eucalypt-species trees are viable in areas of lower rainfall and may be used to provide wood chips for paper production. A genetically-modified variety of blue gum has about one-half the normal lignin content, which is of advantage in paper pulp production.
Plantation eucalypts may be used to manufacture structural timber boards and sections by the o.s.b. (orientated strand board) process. An o.s.b. plant is under construction at Albany in Western Australia, in a new area of eucalypt plantations.
Care must be exercised in the planning of timber plantations to provide fire breaks, to prevent firestorms caused by lightning strikes. At the same time, large area plantings should be linked by corridors of trees, to allow the migration of wild life for pest control.
Adequate and reliable sources of water are essential for a successful plantation industry. Unfortunately, enormous quantities of water are required for drought-proof wide area irrigation, well beyond the capacity of conventional de-salination and pipeline systems. In areas without reliable annual rainfall, reliance must be placed upon plantings of salt-tolerant native and shrubs, such as saltbush. Where it is intended to make use of water which is stored in natural underground acquifers, careful evaluation of natural or artificial replenishment systems must precede development.