In his book The Desert Smells Like Rain Gary Nabhan writes about the Papago Indians who farmed in the Sonoran desert without formal irrigation systems. This Ak-chin farming translates to locating plants below the mouth of washes. In 1913 10,000 acres of crops were still grown by the Papago in this traditional manner, utilizing rainfall, runoff and careful placement of fields. This time of year is crucial to Ak-chin farming as the summer monsoons provide for a season of crops. When the rainfalls soak the soil and carry nutrient rich debris from the washes to the fields, the farmers turn under remnants of spring cover crops and the organic matter from the wash. They plant the native seeds a foot deep so the roots of the plant have access to subterranean water sources. Fine moist sand is sifted over the seeds that send shoots vigorously up to the light. The native crops ripen quickly in 60-80 days. This is a practice that has been perfected over generations and generations of desert farming.
Prime farm land rested downhill from ephemeral streams or washes. Carefully laid out channels carried the trickle of water into basins where the crops were grown. Brush was laid in perpendicular baffles to slow the incoming streams of water and to allow detritus and nutrients to be distributed. Modern soil scientists have discovered the flotsam of a desert wash to be extremely high in nitrogen and organic materials.
In addition, earthen reservoirs or charcos were dug nearby to collect rainfall during the summer downpours and store it for later use on the fields. These shaded cisterns (alquives in Spanish) were constructed uphill from the crops so gravity could do the work.
The crops were grown in clusters, with each individual plant benefiting from those grown around it. The Three Sisters is a well known Native American plant community. Corn seeds are planted first and the stalks provide support for the beans planted around them. The beans roots harbor bacteria which fix nitrogen in the soil for an all-natural fertilizer. Squash is planted around the beans, and these fast growing vines spread lavish leaves that shade and cool the soil and preserve moisture. Pollinating insects move freely among the clusters of crops.
These practices are dying out as the fields, canals and charcos have not been maintained in modern times. Many Native American farmers went to work on large irrigated commercial farms. The demands of growing metropolises on the underground aquifers deplete the subterranean water sources. But Dr. Nabhan points out the lessons of the ancients may still prove important to the science of farming in the desert.
Dr. Gary Nabhan is an internationally-celebrated nature writer, seed saver, conservation biologist and sustainable agriculture activist. He is the author of many books, including The Desert Smells Like Rain, a collection essays on the O’odham peoples of theSonoranDesert. Dr. Nabhan’s “Twelve Lessons on Water Conservation from Traditional Farmers of the Colorado Plateau” may be found at garynabhan.com/i/archives/364 .