Here in Illinois, surrounded by the vast acreage of
agricultural corn and beans, we have a special vantage point from which to
appreciate our ancient heritage of agriculture. Seeing the corn emerge from the
ground, well past danger of frost, renews that annual feeling of optimism that this
will be a good harvest year.
It is easy to forget that, with all our modern technology of
machinery and global positioning systems to aid our efforts, we have the
ancient Olmec people to thank for the basic technology on which all of this is
founded. After all, they have not only been cultivating maize (an alternative
term for corn, based on its botanical name Zea
mays) for several thousand years, they purposely selected seeds year after
year for traits such as larger kernels, increased number of rows of kernels,
and the ability of an ear to hold onto its seeds long enough for it to be
harvested.
They developed
agricultural systems, too. The milpas
of Guatemala and Mexico are maize fields in which a dozen or so crops are grown
together. Melons, tomatoes, amaranth, squash and beans are often included.
According to archeologists and others, the crops grown are nutritionally
complementary. They say that the amino acid composition –the building blocks of
protein - of the different plants complement each other. In that way, complete
proteins can be had, and nutritional deficiencies can be avoided.
Apparently, the milpa system
of growing corn was imported and dispersed throughout what is now the United
States along with the corn itself. In
the northeastern U.S., for example, the Iroquois teach the growing of corn, beans
and squash together in a system called “Three Sisters” gardening. The Legend of
the Three Sisters indicates the strong cultural, and even spiritual, connection
that existed between people and the food they cultivated.
Nutritionally, corn and beans combine to provide complete
protein. Agriculturally, beans fix nitrogen in a symbiotic relationship with
soil microbes. That is, the microbes take gaseous nitrogen from the air and
transform it into a form plants can take up and use. The nutrients become
available to the high-nitrogen-using corn the following year. Modern farmers in Illinois use a system of
rotation to accomplish a similar benefit from growing soybeans. Other beans, or
legumes, as they are also known, can
provide this benefit. Thus, clovers and vetches are often used as cover crops
for that purpose.
The development of maize as a food source is an intriguing
and astonishing story, the roots of which are as yet not entirely clear. It
almost certainly began with a grass-like plant called Teosinte (from the Nahuatl
“grain of the Gods”), and is thought to have been aggressively bred by
people in or near southern Mexico over six thousand years ago. Maize researchers
speak of landraces, or locally-adapted genetic types of maize. At least fifty
genetically distinguishable types have been identified in Mexico alone.
Estimates of as many as five thousand landraces may exist in the southern
Mexico-Central American region.
American farmers of today still rely on the development of
genetic types – or cultivars, as we now call them (for cultivated variety). Thousands of corn cultivars have been
developed and hybridizing is an ongoing process, allowing farmers to select the
ones best suited to their growing conditions.
So, the cycle continues, and most certainly will continue
indefinitely. As we watch and wait for yet another harvest, it is good to take
a step back and appreciate the heritage we have received from those who have
gone before and made life as we know it possible.
