Leguminous Grain Crops

or legume crops, plants of the family Leguminosae, subfamily Papilionaceae (Lotus), raised primarily for their protein-rich grain (or seeds).

More than 60 varieties of legume crops belonging to 17 genera are known in world production. Legume grain is enormously important for food and feed. It is used for food in whole form or in the form of groats and flour; it is also canned and concentrated. Legume grains contain an average of 20–40 percent protein for dry substances (up to 61 percent in lupine), including amino acids necessary for human and animal diets—lysine, triptophan, cystine, methionine, valine, and others—as well as carbohydrates, fats (especially soybeans and peanuts), and vitamins (C, the B complex, and provitamin A). The caloric content of legumes is 3.5 times higher than that of potatoes and six times higher than that of cabbage. One hectare (ha) of legume planting produces 300–800 kg of protein (up to 1 ton with high yields). Legume grain, oil cake, groats, and bulk greens are valuable, protein-rich feed for livestock. The grain of some legumes is a raw material for obtaining casein, adhesive (vetchling and soybeans), and plastics. The enzyme urease, which is found in jack bean seeds, and bean protein are used in medicine. Nodule bacteria form on the roots of legume grains; they enrich the soil with biological nitrogen by assimilating it from the air. Thus, legume grains are good forerunners for spring grains and industrial crops. Lupine, maple tea, and other legume grains are planted for green fertilizers.

The most common legume grains in world farming are the soybean (primarily in the USA, the People’s Republic of China, Brazil, the USSR, and Indonesia); peas (in regions with moderate climate in Asia, Europe, and America); lentil, vetchling, and beans (in the Mediterranean countries, India, Afghanistan, and Argentina); the kidney bean (in Asia, Europe, and America); and the chickpea (primarily in India). Other crops, such as lupine, black-eyed pea, mungo bean, and jack bean, occupy smaller areas. In 1970 the area planted with legume crops (excluding soybeans) was 63.1 million ha and the gross grain harvest was 44.4 million tons. In the USSR in 1970, 5.1 million ha were occupied by legume grains; grain production was 7.62 million tons; and the average yield was 14.9 centners per ha.