Greening the desert

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For years, many scientists have been making dire predictions of widespread irreversible ‘desertification’ in the African Sahel. But recent findings have proven them wrong.

1. Description

2. Why

3. How

4. Future Trends

5. Related Links

Description

The single most definitive factor of a desert is a lack of water circulating in the environment. To prevent desertification, this water must be in a form immediately available to beings living there; not in a deep subsurface aquifer, hoarded by one particular specie, thermally or chemically bound, or in clouds floating overhead.Water is circulated in a bios to a much greater level than it is actually consumed. For our present purposes, we will consider the water taken out of the environment via photosynthesis to be negligible, because it is balanced by the water liberated when carbohydrates, fats and proteins are metabolized. The more the gift of water freely moves in an environment, the less chance a desert has of taking hold.Our great deserts, such as the Mojave in the United States and the Gobi in central Asia, may simply be too far from a source of rain derived from evaporated seawater to be anything but a desert.

Why

Water resources in the world are scarce and unevenly distributed. In deserts, the only source of water is groundwater, often saline and of poor quality. This limits agricultural activities. In those places where farming does occur, groundwater levels have dropped dangerously due to overexploitation.However, deserts contain several resources which could be combined to help solve this problem in a relatively simple way: ample solar and fossil energy, and the magical ingredient, gypsum. Peter van der Gaag and colleagues have hit the idea of utilizing the untapped energy from oil and gas flare-off, or solar power, to release the water locked in the abundant rocks.Van der Gaag has already discussed the technology with people in the Sahara who agree that the idea could help combat water shortages, improve irrigation, and even make deserts fertile. As it happens, gypsum is also a very useful agromineral. 

How

A group of European scientists has come up with a suggestion on how to green deserts. Gypsum, a rocky mineral abundant in desert regions where fresh water is usually in very short supply, could become a new resource out of which trillions of liters of clean drinking water can be squeezed. The engineers of the ‘Holland Innovation Team’ describe their proposal in a special issue on ‘Macro-Engineering’, published in the International Journal of Global Environmental Issues.

  • Solar module: a series of wafer-thin silicon cells covered in a protective tempered glass, it converts solar radiation into DC electricity.
  • Wires: these vary greatly in size and cost depending on the size of the system
  • Charge controller: an electronic device that controls the charge going into the battery bank in order to prevent an overload. Some charge controllers come with added features such as digital displays, maximum power point trackers (MPPTs), and low voltage shut disconnects.
  • Battery bank: stores the energy for future use. The battery bank can be as small as two batteries or as large as the loads require.
  • Inverter: an electronic device that changes low voltage DC electricity stored in the batteries into high voltage AC electricity.
  • DC loads: these batteries store electricity in DC form, so it is more efficient to power up DC loads. This is usually only done in remote settings where twelve volt lighting can be used.
  • AC loads: AC is what powers most household item

Researchers in Japan have found a way to help plants survive better in deserts and areas with lots of sun by neutralising the active oxygen species (such as hydrogen peroxide) that kill plant cells. They hope their technique will make it easier to grow food and fruit in desert areas.In strong sunlight plants close their stomata to prevent water from evaporating. But this also slows down photosynthesis, since less carbon dioxide gets into its leaves. And cells die because the energy that would have been used in photosynthesis is used to create active oxygen.Scientists at the Research Institute for Innovative Technology of the Earth (RITE) and the Agriculture department at Kinki University Osaka have found a way to dissolve this active oxygeThey injected an enzyme-producing gene from bacteria which live in the human colon into the chloroplast of a tobacco plant. The enzyme, called catalase, turns the active oxygen into water. The researchers tested their altered plant by putting it side by side with an unaltered plant under light from six 450-watt sodium lamps. While the altered plant thrived, the ordinary plant withered after two days.Although tobacco is not an appropriate plant for greening deserts, it was easy to work on because the plant has been widely studied and genetically manipulated, says chief researcher Ken'ichi Tomizawa."We have been using tobacco just for the basic research. In the next step we need to think about which plant would be best for experiments in the field." Tomizawa says local standards of living will dictate the type of plant they use. "Developing countries need food plants, but countries like Israel need other types of plants, such as fruit or cash crops."

Future Trends

Acoustic bubble traps can be used to investigate the behaviour of single bubbles in liquids as well as few bubble systems under controlled conditions. The aim is to arrive at a better understanding of cavitation phenomena. These are important for sonochemistry and medical applications of ultrasound. Cavitation bubbles also provide a rich laboratory for basic research in nonlinear physics.

Keywords

Greening the Desert, Fukuoka, Natural Farming, Abu Dhabi Greens, Desertification

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