Rubber soles for crops

IF SCIENTISTS at the Center for Irrigation Technology (CIT), at the California State University, Fresno succeed, the millions of scrap tyres that litter the landscape would well be buried underground and serve to conserve water and reduce the need for irrigation, whether in Califbrnia golf courses or grass-lands in Africa or croplands in India.

Bob Hendershot, president of Tire Farms, of Santa Rosa, a company which disposes of old tyres, maintains that water collecting in the wells of the tyres would slash the cost of keeping the golf courses green (New Scientist, Vol 145, No 1974). In Hendershot's Rain Trap system - which be has patented - old tyres are split around the middle, and buried a foot underground. Water collects in the half tyres, preventing it from seeping away. A typical 18-hole golf course would use up 1.2 million scrap tyres, and the owner would save between us $10,000-70,000 a year in irrigation costs, claims Hendershot.

CIT scientists have begury to test the feasibility of the scheme. They have buried tyres in 3 different configurations, and left a fourth plot empty as a control. Researchers will water the plots through the spring, then stop irrigation and see how long the grass stays green in each plot. Tests will assess how much water could be saved by the tyres, and whether half tyres will work their way to the surface as whole ones tend to do in rubbish dumps.

Some 60 per cent of the 250 million tyres discarded in the us each year are dumped. Says Hendershot, "If we planted tyres in only 34 per cent of the new golf courses built each year in USA, we would use up cvery available scrap tyre."

Meanwhile, a British firm, Fibrescreed, has developed recycled rubber products for use in road construction, reports PTi Science Service. The company has produced a rubber chip material which can be used for repairing cracks in highways and airport runways.

And, in southern England, a project is underway to utilise old tyres in coastal protection. If the project, which among other things investigates the action of salt water on the tyres, succeeds, a tyre- reef will be built in Poole Harbour on the Dorset coast in southern England as a protection against the tides.