Before we thought the water supply would last forever (or at least several political cycles), we had dry farming. As the worst drought in decades grips the U.S., dry farming is getting a second look.
Farmers see the horizon, and there’s not much water on it (The "global water shortage is now 'chronic’" according to a UN report). In the U.S., the federal government has added at least 218 more counties to the list of natural disaster areas, now more than half of the total counties in the U.S. are low on water.
Dry farming, while not designed to counter the worst droughts, "evokes the image of a wet sponge covered with cellophane," writes Brie Mazurek, the online education manager at the Center for Urban Education about Sustainable Agriculture (CUESA).
By tapping the moisture stored in soil to grow crops, rather than using irrigation or rainfall during the wet season, dry-land farming was a staple of agriculture for millennia in places like the Mediterranean, and much of the American West, before the rise of dams and aquifer pumping.
During the rainy season, farmers break up soil then saturated with water. Using a roller, the first few inches of the soil are compacted and later form a dry crust, or dust mulch, that seals in the moisture against evaporation.
In places like California, where the expensive (and fast evaporating) irrigation systems of the Central Valley are seen to be running on borrowed time, dry farming has begun to spread among a small cadre of farmers along the coast where dry farming was once standard practice since the undeveloped coast line would support little else.
Farmers like David Little of Little Organic Farm, reports Mazurek, are rescuing old ways for modern applications. "In the beginning, I searched out people who were known dry-farmers," says Little, who started farming in 1995, in the report. "It seemed like no one had done it for 30 years or so." Little now grows potatoes on 30 acres in Marin and Petaluma counties in California.
Yet dry farming is unlikely to win over farmers who still have abundant access to water, fertilizer, and big markets. "Dry farming is not a yield maximization strategy," says the California Agricultural Water Stewardship Initiative. "Rather it allows nature to dictate the true sustainability of agricultural production in a region."
In place of huge yields and produce (fruit and vegetables may grow twice the size of their dry-land counterparts), farmers get smaller, hardier crops with several times the flavor (the water stress concentrates sugars and nutrients), but the yield penalty in bad years is steep: 12 tons per acre for apples, compared to 30 to 40 tons produced by large apple farms in the Central Valley, reports CUESA, and even worse results for drought-ravaged grains in places such as Idaho, reports NPR.
But dry-land farming is not about using as much resources as possible to optimize a year’s yield. It’s about making do with less without jeopardizing the future’s harvest. "The coast of California used to be our main source of food in the state, until they started developing farms in the Central Valley because of all the water," Little said to CUESA. "Now they’re running out of water."