San Joaquin Valley (US) is doomed by salt

Along Interstate 5 between Los Angeles and San Francisco, one is greeted by an endless sea of agricultural fields. These are the large-scale and highly productive farms of the San Joaquin Valley. What is incredible is that they exist at all. Given the arid conditions of the area, it is a miracle that anything – aside from cacti and scrub – is able to grow there.

As University of California Berkeley Professor Emeritus, James Parsons already wrote in 1987: “The southern part of the valley was a barren desert waste with scattered saltbush when first viewed by Don Pedro Fages in 1772 coming from the south over Tejon Pass.”

“Less than five inches of rain annually falls in southwestern Kern County, maybe ten inches at Fresno. Pan evaporation in a summer month on the west side pushes 20 inches.”

[Joe Mathews: Irrigation of fields in the San Joaquin Valley]

Still, the barren desert wasteland and parched conditions observed by Fages nearly 250 years ago, including a negative water cycle, didn’t stand in the way of what was to come. With several mega water diversion projects, federal and state subsidized water plus cheap migrant field workers, mankind was able to create what has been called “the world’s richest agricultural valley, a technological miracle of productivity.”

Yet to sustain this miracle it needed endless dumping of chemical fertilizers, pesticides and herbicides. It also needed imported water, but irrigated on sandy soil is not without consequences. What has stimulated the productive miracle of the San Joaquin Valley over the last century is the same blend of factors that has propped up America’s financial markets and blown out government debt loads over this same period: cheap credit and excess liquidity.

In his novel 'Cadillac Desert', an account of the development of the American mid-West, Marc Reisner offers the following characterization on the insanity of water resource development: “Like so many great and extravagant achievements, from the fountains of Rome to the federal deficit, the immense national dam-construction program that allowed civilization to flourish in the deserts of the West contains the seeds of disintegration; it is the old saw about an empire’s rising higher and higher and having farther and farther to fall.

Without the federal government there would have been no Central Valley Project, and without that project California would never have amassed the wealth and creditworthiness to build its own State Water Project, which loosed a huge expansion of farming and urban development on the false promise of water that may never arrive.”

[Joe Mathews: Pistacioorchard in the arid valley]

In the San Joaquin Valley, vast irrigation networks convey water thousands of miles to make the desert bloom. But as surface water is conveyed along the open California aqueduct, it both evaporates and collects mineral deposits. The combination of these factors concentrates the water’s salt content. Then, as it is applied to irrigation, the residual salts collect in the soil.

After decades of this, along with the over-application of fertilizer through mechanized fertigation systems, the salt in the soil has built up so that it strangles the roots of the plants. To combat this, over-watering is required, because the irrigation water – while salty – is fresher than the salt encrusted soil. By applying excess irrigation water, the soils around the plants are temporarily freshened up so that crops can grow.

Yet, at the same time, this over-watering accelerates the mass quantity of salt being applied to the soil. There is no outlet for the salt to flush to, because the valley is the basin’s terminus. Thus, in this grand paradox, the relative freshness of the excess water that is keeping the farmland alive is, at the same time, the source of the salt that is killing it.

Reisner further explains: “Nowhere is the salinity problem more serious than in the San Joaquin Valley of California, the most productive farming region in the entire world. There you have a shallow impermeable clay layer, the residual bottom of an ancient sea, underlying a million or so acres of fabulously profitable land. During the irrigation season, temperatures in the valley fluctuate between 90 and 110 degrees; the good water evaporates as if the sky were a sponge, the junk water goes down, and the problem gets worse and worse. Very little of the water seeps through the Corcoran Clay, so it rises back up to the root zones — in places, the clay is only a few feet down — water logs the land, and kills the crops.”

Yup, the salty crop fields in the San Joaquin Valley are doomed.

[Adapted from an article by MN Gordon]