Pollution blamed for lower crop yields
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CTA. 1995. Pollution blamed for lower crop yields. Spore 59. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/47158
Ozone, which is produced in the large cities of the South as well as the North, is spreading to rural areas and reducing' crop yields. The effect is probably made worse by high temperatures. These findings are revealed by research at Imperial...
Ozone, which is produced in the large cities of the South as well as the North, is spreading to rural areas and reducing' crop yields. The effect is probably made worse by high temperatures. These findings are revealed by research at Imperial College, London, Alexandria University, Egypt, and the University of the Punjab in Lahore, Pakistan. It has been recognized for some years that ozone was affecting crops in Northern countries, but this work shows Southern crops are affected just as badly, if not more so. Ozone results from a photo-chemical reaction when sunlight shines on nitric oxide and other compounds produced by car exhausts and industry. Ozone levels in Southern cities are rising as car ownership increases and industry expands. Nitric oxide will also destroy ozone as it falls to ground level which can reduce ozone pollution in cities. But as ozone levels increase and more is being blown out to the countryside where there are fewer vehicles and less nitric oxide, so ozone levels are rising and affecting crops. Trials demonstrated that in Egypt, where radish and turnip crops were treated with a chemical that neutralized the effect of ozone, yields were 20% higher than in untreated crops. In Pakistan, wheat and rice were grown in containers fed with filtered air, and these crops produced about 40%, more grain and straw than crops crown in a typically ozone-polluted atmosphere. Having proved that ozone is a factor in reducing yields, Professor Nigel Bell and Dr. Mike Ashmore, of Imperial College have been contracted by the British Overseas Development Administration (ODA) to carry out further studies, and to look at ways of coping with the problem. This will involve finding crops and varieties that can tolerate higher levels of ozone, and examining how farming systems can be modified to withstand ozone. Professor Bell is particularly worried about the effect of ozone on traditional crop varieties. Centre for Environmental Technology Imperial College 43 Prince's Gardens London SW7 2PE, UK
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