Making deserts bloom -- using Japanese rice husks
Tokyo — Rice and cereal husks usually discarded by farmers as a dusty nuisance could be one answer to a global problem: the advance of deserts. Wasteland could be reclaimed for agricultural use, significantly boosting world food production, if experiments getting under way in Tottori on the south coast of Japan's main island of Honshu prove capable of widespread application.
Some desert countries already have no doubts. Kuwait hopes to apply the technology to its unwanted sand next year if possible, while Abu Dhabi is likely to follow suit.
The Japanese idea is to specially bake the husks left over from the machines that polish rice and remove the husks. At present, baked husks are used mainly for packing fruits and fertilizer.
Known as kuntan in Japanese, the carbonized rice husks are baked on a nickel chromium plate, producing a sponge-like material with remarkable water absorption and retaining capacity.
One kilogram (2.2 pounds) of kuntan, for example, can retain an average 6.8 kilograms (15 pounds) of water.
In comparison, ordinary mud in a rice paddy averages only 350 grams (0.8 pounds) of water retention per kilogram. The material also readily absorbs sunlight and air to nourish plant roots.
Used as a semi-artificial farm soil at an agriculture experimental station near Tokyo, it has already doubled the normal harvest of cucumbers.
Now kuntan's ability to turn back the deserts is to be tested on the scenically attractive coastal sand dunes of Tottori, long a major tourist attraction.
A giant vinyl sheet will first be laid down to prevent water from escaping underground. A mixture of kuntan and dirt will be laid on top, and this will be covered by a heat-insulating net at night.
Growing crops on a vinyl bed in desert areas is not new. The Desert Development Technology Agency of Tokyo says it pioneered the technology in Abu Dhabi during the 1970s.
Middle East nations have also tried other methods, such as laying an asphalt bed or using water sprinklers. But such efforts have encountered difficulties through high cost and the need for abundant water supplies.
Kuntan overcomes these difficulties handily, claims the Kansai Sangyo Company , which is spearheading the Tottori project.
A thousand square meters of farmland can be created with 300 kilograms of rice husks produced at an incredibly low cost of less than $1, says company president Masahiro Kojima. The vinyl sheets and ordinary soil needed would not significantly add to the costs.
''This is one of the major attractions of this effort when you consider that many deserts are in poor, underdeveloped countries without the resources to tackle the problem,'' he adds.
In many poor nations, however, such as India, even such small costs would prove too high for most farmers. And getting government bureaucracies to promote these techniques could be difficult.
Kojima also envisages exporting husk-carbonizing machines and other processing equipment to other countries in Asia that now have trouble disposing of unwanted rice husks. And he stresses that other cereal crops with husks could work just as well.
In 1974, the United Nations General Assembly adopted a unanimous resolution urging international cooperation to halt the spread of deserts.
Japanese officials say an estimated 5 to 6 million hectares are lost to the advancing sands each year due to various factors, including slash-and-burn farming popular in some poor countries.
Annual farming losses from desert encroachment are placed at about $16 billion.