Uses for vegetable wastes.

VE. EGETABLES are important but wasteful. Twenty-odd kinds of plants are commonly grown for vegetables in the United States. In every State they are grown commercially; the highest concentrations are in California, New York, Texas, and Wisconsin; returns from them to growers approach 300 million dollars a year. But not more than 20 to 30 percent of the crop is eaten. The waste portions—4 million tons of them—are mostly leaves. Some wastes are left on the ground to be plowed under; some are fed; some are discarded in dumps; some are a plain nuisance; a tiny fraction is artificially dried for feed. The most conspicuous constituent of the wastes is water—about 75 to 90 percent. One of the tasks assigned to the Eastern Regional Research Laboratory was to find further uses for vegetable crops. We found out soon enough that if any of these widely scattered, widely diverse wastes were to be utilized industrially certain conditions had to be met. The materials must contain some valuable constituents. For most uses they must be dried, partly for preservation, partly to cut down transportation costs. They must occur abundantly in a restricted area, to minimize hauling to the drier or other processing unit. A succession of wastes must be available, in order to keep a drier occupied for as long a season as possible. Two of the requisites—the chemical composition and the preparation of dried material—are technical questions, and we have directed our attention mosdy to them. The others are questions of economics and have to be answered mainly by the person who is considering the exact location of a plant to use the wastes. Because leaves are the manufacturing parts of the plant, we would expect them to be high in valuable constituents. And they are: Meal