There will always be enough food, one USDA official postulated, explaining, "The population will never outstrip the food supply." A very simple precept: no food, no people.

In spite of this simplistic theory, the Department of Agriculture has chosen to discuss the future of the world's food supply in its 1981 yearbook entitled, "Will There Be Enough Food?"

The subject was hand-picked by Secretary of Agriculture John Block, a farmer himself, who introduced the 300-page-plus yearbook at a press reception Tuesday.

Before a backdrop of a 2 1/2-ton food display -- food for a family of four for a year -- the red-white-and-blue-clad Block said that agricultural research and land-water conservation are the "two principal missions of the USDA." In a red-white-and-blue speech he said the free enterprise system was responsible for the United States' leadership in food production.

Predictably, the USDA responded with a collective "yes" to the question posed by the yearbook's title. There will be enough food, said Block. "We can do it. We're committed to doing it."

Many of the book's authors predict that demand on the U.S. food supply will grow faster than the food supply itself. Agricultural research, they say, can support conservation efforts. The book reports that "erosion has destroyed the productivity of much of our land," washing away 50 percent of American topsoil in the last 100 years.

Research must continue, says one author, in tilling methods that preserve topsoil; developing machinery that allows farmers to plant without stripping their fields, and increasing plant yields.

But optimisim prevails throughout the book; authors cite examples of budding research that has the potential of improving domestic agriculture. Improved irrigation procedures may save diminishing ground water supplies. Biological pest control eliminates the use of destructive pesticides.

The book describes a futuristicmarketplace where computers can save fuel by controlling food storage and transportation, where railcars use solar energy to refrigerate food and where breakthroughs in preservation techniques extend the shelf life of even fresh foods. Marketing techniques are examined, as is the consumer's role in the food system.

Issue might be taken with some of the premises presented. While authors take a fairly progressive approach toward agriculture and research, the specialists who describe marketing and consumerism are a little more conservative. One author implies that consumers pull all the strings on marketing techniques (with little regard for advertising, etc.) and another lauds the use of chemical additives in food.

In all, the book is a fairly staid, comprehensive examination of the role the U.S. food system will play in the future of the world.

The yearbook has an 82-year tradition of disseminating agriculture information. With three exceptions ("Trees," "Insects" and "Soil") yearbooks from 1948 remain in print. "Consumers All," the 1965 yearbook, has received widest distribution and has gone into additional printings (even being published commercially).

Copies of this yearbook may be requested from your representatives or senators. In addition, they may be purchased by sending $7 per copy to the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.