Dry Farming and Drought-Tolerant Crops — What Climate Change Is Going to Ask of Us

The problem

Irrigated agriculture supplies roughly 40% of global food calories from about 20% of cultivated land. It depends on river systems (Colorado, Indus, Yangtze, Nile) and aquifers (Ogallala, North China Plain, northwestern India) that are nearly all overdrawn. The Ogallala, beneath the American High Plains, has lost roughly 30% of its volume since 1950.

Climate change is shifting precipitation patterns in ways that will reduce irrigated supply in many of the world's breadbaskets. The food system response over the next 50 years will involve, among other things, more dry-farmed and drought-tolerant cropping.

Dry farming, defined

Dry farming is the practice of producing crops on rainfall alone — no irrigation. It depends on:

Crop selection (varieties bred for low water).
Soil management (deep tilth, mulch, organic matter to hold moisture).
Planting density (lower than irrigated agriculture).
Timing (planting to use winter rain, harvesting before peak summer heat).

It produces lower yields per acre than irrigated farming. It produces more concentrated flavor (dry-farmed tomatoes are documentably more flavorful) and more nutritionally dense food. It uses zero water beyond what the sky provides.

Crops worth knowing

Sorghum (milo). Drought-tolerant grain. African origin. The fifth-largest cereal crop globally. Used heavily in West African injera-like flatbreads, US Southern syrup-making (sorghum syrup), and Indian roti.
Millet. Several species. Pearl millet, finger millet, fonio. African and Asian origins. Higher protein than rice, lower water requirement, naturally gluten-free. Fonio (West African) is especially worth seeking out; Pierre Thiam's Yolele Foods is making it available in the US.
Teff. Ethiopian. The grain of injera. Extremely drought-tolerant.
Amaranth and quinoa. Andean. High protein, drought-tolerant, also tolerant of poor soils.
Cassava (yuca, manioc). Tropical Americas origin, now ubiquitous in West Africa. Survives where almost nothing else grows.
Tepary bean. Indigenous to the American Southwest (Tohono O'odham). One of the most drought-tolerant crops on Earth.
Heritage wheat varieties like Sonora wheat — bred for low-water Southwest cultivation.

The Tohono O'odham example

The Tohono O'odham of the Sonoran Desert have farmed tepary beans, cholla cactus buds, mesquite pods, and squash on rainfall alone for centuries. Native Seeds/SEARCH, based in Tucson, preserves and distributes their seed varieties. The agronomy works. It produces less food per acre than irrigated Iowa corn, but it produces it on no water — and continues to produce in drought years that wipe out irrigated systems.

What to do as a cook

Try sorghum, millet, teff, fonio. Real grocers carry at least one of these. Asian and African grocery stores carry all of them.
Read Gary Paul Nabhan's Coming Home to Eat (2002) and Renewing America's Food Traditions (2008) on regional drought-tolerant cultivars.
Subscribe to Anson Mills, Hayden Flour Mills, or Bluebird Grain Farms — small US grain producers focused on heritage low-water varieties.

Reading

Gary Paul Nabhan, Coming Home to Eat (2002).
Dan Saladino, Eating to Extinction — chapters on drought-tolerant grains.
Pierre Thiam, Yolele! (2022) — the fonio case.

The dry-farming practice

Dry farming — agriculture without irrigation, relying on stored
soil moisture and rainfall — is one of the oldest cultivation
traditions and one of the most relevant to climate-adapted
agriculture. The practice was the default across most of human
agricultural history; widespread irrigation is a 20th-century
phenomenon enabled by industrial pumping.

Dry-farmed crops include grapes (the traditional Mediterranean
viticulture), olives, certain wheat varieties, certain stone
fruits, and a handful of vegetables (notably dry-farmed tomatoes,
which Molly Watson's writing has documented for the contemporary
Central California farming scene).

The flavors are different. Dry-farmed tomatoes are smaller, more
concentrated in flavor, with higher sugar-to-acid ratios than
irrigated versions. The same pattern holds for many dry-farmed
crops; the constraint produces flavor intensity.

The drought-tolerant grain shift

The grains worth attention as climate adaptation accelerates:

Sorghum. African and Asian origin. Drought-tolerant. Used
extensively in African and Indian cuisines; underused in the
US except as livestock feed.
Millet. Several distinct species (pearl, finger, foxtail,
proso). All drought-tolerant. Foundations of traditional
African and Indian diets.
Teff. Ethiopian grain; the base of injera. Tiny grain;
drought- and altitude-tolerant.
Amaranth. Indigenous American grain; drought-tolerant;
complete protein.
Quinoa. Andean grain; drought-tolerant; complete protein.

Several of these grains are being commercially developed in dry
US regions (the Great Plains is the obvious target for sorghum
and millet expansion).

The water-economy argument

Conventional industrial agriculture uses water in enormous
quantities. California agriculture uses roughly 80 percent of
the state's water; the bulk of that goes to alfalfa and pasture
for dairy and beef. The water economics will not work in a
significantly warmer or drier future.

The practical implication: the foods that will be cheaper and
more available in 2050 are the foods that can be grown without
irrigation. The foods that will be more expensive are the
irrigation-dependent industrial crops.

What home cooks can do

Familiarity with dry-farmed and drought-tolerant ingredients
is a small but compounding hedge. Cook with sorghum, millet, or
teff at least once a month. Buy dry-farmed tomatoes when
available (typically late summer at farmers markets). Drink
dry-farmed wine when available (some California producers
explicitly label it).

The shift in palate over time matters. A generation of cooks
used to dry-farmed flavors will create demand that supports the
producers.