Crop wastes such as straw, corncobs and cornstalks can be converted into livestock feed that provides as much food energy as corn, agricultural researchers have found at the University of Illinois at Urbana-Champaign.

If the conversion process can be made economical, it could mean that more of the grain fed to animals could be used for human food instead, increasing the world's food supply.

Scientists have long known that the cellulose fiber in crop wastes is a carbohydrate that contains as much energy as grain starch or sugar. Although humans cannot digest cellulose, ruminant animals such as cattle can.

However, the tougher parts of many plants, such as the stalks, have much of their cellulose chemically bound to a woody substance called lignin. Even cattle cannot digest the cellulose in this form. The Illinois researchers, led by George C. Fahey Jr., found that if they treated the crop wastes with an alkaline solution of hydrogen peroxide, the same chemical used as an antiseptic, the lignin bonds were broken and the crop wastes became nearly as digestible as corn.

Animals fed a diet heavy with untreated crop wastes lost weight. Similar animals given treated wastes gained weight.

Because 50 percent to 70 percent of a farmer's financial investment in his crop goes to grow the part of the plant that is wasted, the conversion process is economically attractive. However, the cost of drying the wet-treated crop wastes is still too high. Fahey, who reported his findings in the journal Science, said he hopes to develop a less costly alternative.