WASHINGTON (AP) _ Old newspapers may have a higher worth than as wrappings for dead fish. A government scientist says they also can be used to turn hard-packed dirt into crumbly, nutrient-rich soil.

James H. Edwards, a soil scientist with the Department of Agriculture's Agricultural Research Service in Auburn, Ala., reports that by combining newspaper and other ingredients he is growing cotton, corn and soybeans in soil that previously had been so hard that it could be compared to sandstone.

''A fingernail can't penetrate it,'' Edwards said.

But Edwards said he has prevailed over the hard land by using shredded back copies of the Opelika-Auburn News combined with chicken litter mixed with soil.

When cotton plants are grown in the mix, roots reach four feet deep, Edwards said, instead of the six inches common in the Southeast. The roots aren't stopped by the hardpan common to the region, he said.

The recipe Edwards has been using calls for 40 percent shredded newspaper, 50 percent soil and 10 percent to 15 percent of chicken litter.

He uses it to fill a trench four feet deep and six inches wide. The chicken litter causes the newspaper to decompose rapidly, a fact Edwards says is probably due to the microbes and ammonia it contributes to the mix.

Edwards says a two-foot trench might be best for commercial use. And he says he is testing the mix on the surface at depths of only six inches.

''It's a mistake to call newspapers, leaves and grass clippings waste,'' Edwards says. ''They loosen soil, add organic matter, provide nutrients and beneficially effect soil pH.''

Edwards said that in the future he probably will lower the amount of chicken litter he uses to 5 percent or 6 percent to reduce the level of nitrate leaching from the litter.

''The idea is to find the percentage needed to turn the newspaper cellulose into soil-softening humus without having excess nitrates that can harm ground water,'' he said.

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The whitefly, which is threatening California's rich fruit and vegetable industry, also may pose a hazard to food supplies in the developing world, an agricultural expert says.

Robert Zandstra, director general of the International Potato Center, said it has been known for some time that a new insect pest or disease could threaten food supplies in developing countries.

''The early evidence is that the whitefly may fit the bill,'' Zandstra said.

The whitefly is a tiny insect that causes extensive damage to a wide variety of crops. According to the Potato Center's chief entomologist, K. V. Raman, whitefly infestations have been reported in China, India, Egypt, Colombia, Peru and the Dominican Republic.

Scientists working with the Consultative Group on International Agricultural Research, of which the Potato Center is a part, say these recent infestations are the result of the destruction of the whitefly's natural enemies because of the indiscriminate use of pesticides.

''What we now face is a population explosion caused by man, not by nature,'' Raman said. ''Our best chance to control it lies with the large- scale use of integrated pest management practices.''

He said stricter controls on the use of pesticides are needed to help the recovery of insect-eating bugs and parasites, the natural enemies of the whitefly.

He said these whitefly predators are found in just a few developing countries but could be reared and distributed in those places where the whitefly is becoming a problem.

''We can't allow the whitefly to get the upper hand,'' Zandstra said. ''It's not an impossible job to control the whitefly, just a difficult one, requiring in addition to natural enemies, botanical pesticides and the use of selective cropping patterns.''

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The United States is donating 100,000 tons of corn to newly independent Estonia.

Secretary of Agriculture Edward Madigan said the $11 million donation will be sold by Estonia's government to private sector feed millers and poultry producers for feed.

''This donation will help achieve two objectives,'' Madigan said. ''It will supplement Estonia's animal feed supply to help ensure adequate production of meat, poultry and dairy products. And proceeds from the sale will be used by the Estonian government to assist in the development of the country's private sector agricultural economy.''