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similarly land-intensive form of subsistence agriculture

(Figure 14.4). Nomadic herders must continually move

their livestock to find adequate food for the animals.

Intercropping is a form of intensive subsistence agri-

culture that involves growing a variety of plants on the

same field simultaneously. When certain crops are grown

together, they produce higher yields than when they are

grown as monocultures. (A monoculture is the cultiva-

tion of only one type of plant over a large area.) One rea-

son for higher yields is that different pests are found on

each crop, and intercropping discourages the buildup of

any single pest species to economically destructive levels.

Polyculture is a type of intercropping in which several

kinds of plants that mature at different times are planted

together. In polyculture practiced in the tropics, fast- and

slow-maturing crops are often planted together so that

different crops can be harvested throughout the year.

1. What are some differences between industrialized
   agriculture and subsistence agriculture?


2. What are shifting cultivation, nomadic herding,
   and intercropping?

Most farmers in developing
countries practice subsistence
agriculture, the production of
enough food to feed oneself and
one’s family, with little left over to
sell or reserve for hard times. Sub-
sistence agriculture also requires
large inputs of energy, but from
humans and draft animals rather
than from fossil fuels.
Some types of subsistence agriculture require large
tracts of land. Shifting cultivation is a form of subsistence
agriculture in which short periods of cultivation are followed
by longer periods of fallow (land being left uncultivated),
during which the land reverts to forest. Shifting cultivation
supports relatively small populations. Slash-and-burn agri-
culture is a type of shifting cultivation that involves clearing
small patches of tropical forest to plant crops (see Chapter
13). Slash-and-burn agriculture is land-intensive; because
tropical soils lose their productivity quickly when they are
cultivated, farmers using slash-and-burn agriculture must
move from one area of forest to another every 3 years or so.
Nomadic herding, in which livestock is supported
by land too arid for successful crop growth, is a

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subsistence

agriculture

Traditional agricultural

methods that are

dependent on labor

and a large amount

of land to produce

enough food to feed

oneself and one’s

family.

354 CHAPTER 14 Agriculture and Food Resources