What is a Milpa?
The
following
is
taken
from
Charles
G.
Mann, 1491:
New Revelations of the Americas
Before Columbus,
Alfred A. Knopf, New York, 2005. pp. 197-199.
Indian Farmers grow maize in what is called a milpa . The term
means “maize field” but refers to something considerably more
complex. A milpa
is a field, usually but not always
recently cleared, in which farmers plant a dozen crops at once,
including maize, avocados, multiple varieties of squash and bean,
melon, tomatoes, chilis, sweet potato, jicama, amaranth (a grain-like
plant), and mucuna (a legume). In nature, wild beans
and squash often grow in the same field as teosinte (an ancestor of
corn), and beans using the tall teosinte as a ladder to climb toward
the sun; below ground, the beans nitrogen-fixing roots provide
nutrients needed by teosinte. The milpa is an elaboration
of this natural situation, unlike ordinary farms, which involve
single-crop expanses of a sort rarely observed in unplowed landscapes.
Milpa crops are nutritionally
and environmentally
complementary. Maize lacks the amino acids lysine and tryptophan,
which the body needs to make proteins and niacin. Beans have both
lysine and tryptophan, but not the amino acids cysteine and methionine,
which are provided by the maize. As a result, beans and maize
make a nutritionally complete meal. Squashes, for their part,
provide an array of vitamins; avocados, fats. The milpa, in the
estimation of H. Garrison Wilkes, a maize researcher at the University
of Massachusetts in Boston, “is one of the most successful human
inventions ever created.”
Wilkes was referring to the ecological worries that beset modern
agribusiness. Because agriculture fields are less diverse than
natural ecosystems, they cannot perform all their functions. As a
result, farm soils can rapidly become exhausted. In Europe and
Asia, farmers try to avoid stressing the soil by rotating crops; they
may plant wheat one year, legumes the next, and let the field lie
fallow in the year following. But in many places thins only works
for a while, or it is economically unfeasible not to use the land for a
year. Then farmers use artificial fertilizer, which at best is
expensive, and at worst may inflict long-term damage on the soil.
No one knows how long the system can continue. The milpa, by
contrast, has a long record of successs. “There are places in
Mesoamerica that have been continuously cultivated for four thousand
years and are still productive.” Wilkes told me. “The
milpa is the only system that
permits that kind of long-term
use.” Likely the milpa
cannot be replicated on an
industrial scale. But by studying its essential features,
researchers may be able to smooth the rough ecological edges of
conventional agriculture. “Mesoamerica still has much to teach
us.” Wilkes said.
