VEGETABLES - World Food: Production and Use - page 140

Figure 4.10. Shard growing in A´de and Zoro's garden in Ecuador. (Courtesy of David Cer ´ n.)

4.7 LEAFY VEGETABLES

Leafy vegetables are those vegetables where it is the leaf that is eaten. They are a
common food around the world and are eaten fresh or cooked, often boiled, as part
of meals. Of the common leafy vegetables listed, more than 50 percent are from the
genus Brassica as can be seen in Table 4.3. Note that chard (Fig. 4.10) is in the
genus Beta and so is related to beets, the tops of which are also eaten as leafy vegetable.

4.7.1 Climatic Adaptation
Leafy vegetables are grown and adapted to a wide range of climatic conditions, as seen
in Table 4.3. They are all suited to temperate climatic zones, although some do particu-
larly well in subartic zones, for example, cabbage, and others in tropical zones, for
example, Chinese cabbage; see Figure 4.11. Leafy vegetables are grown in rows and
sometimes, particularly in home gardens, in raised beds. They need fertile soil and
respond well to both organic matter additions to soil and to chemical fertilization.
Many of the leafy vegetables do better in cooler climates and so are not commonly
grown in tropical climates.

4.7.2 Importance in Human Nutrition
As seen in Figure 4.12 leafy vegetables tend to be moderate in protein and low in fat and
so are not a particularly good source of these nutrients. They are highest in carbohydrate
relative to the other nutrients and are high in fiber relative to protein and fat and so can
be an important source of this dietary component. Kale, however, has moderate levels
of carbohydrate when compared to the other leafy vegetables and is thus less valuable
as a source of this nutrient.