Some agricultural experts predict a return to "dryland farming" in many parts of the American West. Yet if this change is forced by the mounting costs of irrigation, it will not come without imposing other hard-to-calculate costs.
Even those who see the change as wise, or at least inevitable, wonder if this country can afford to lose the food, and the increasing earnings from its export , produced by the vast irrigated areas stretching from Texas to the Dakotas and across to California.
One way or another, however, Americans should expect to hear more about dryland farming -- both from farmers bitter that high energy costs and now farm-product prices are forcing them to abandon irrigation, and from conservation- ists arguing that excessive irrigation squanders a precious and limited natural resource.
Compared to all the theories swirling around it, dryland farming itself is easy to define. it simply means relying on annual rainfall to water crops -- which may be fine unless a farmer's area is in the grip of a severe drought, such as this years drought in the Midwest, or is in an area such as El Paso, Texas, where the average annual rainfall can be six to eight inches, most of which falls at the wrong times of the year. Dryland farming was practiced up to the 1940s in most areas, and still is practiced from the East Coast to about halfway across the United States.
The dryland technique still has its advocates, even in marginal areas like western Kansas, where wheat farmer Ken Jorns says: "There's an old saying in Kansas that your dryland farmer doesn't make much money, but it takes him a long , long time to go broke."
But more and more farmers have taken the risk of investing heavily in irrigation equipment to cut down the risks of losing crops in dry years. And so , to grow crops successfully in the West's drier areas, a massive irrigation network has developed. California Gov. Edmund G. Brown Jr. currently is trying to add to this network with a $5.1 billion project centering on a 43-mile canal that would divert Sacramento River water south into the San Joaquin Valley and southern California.
Texas corn growners would love to see a similar project in their state. They have their eyes set on Mississippi River water -- because they are spending up to $17,000 per well to drill down 500 feet to tap the steadily diminishing supplies of the Ogallala aquifer.
For many Texas-to-California farmers relying on irrigation, the economics of the situation are obvious. Either they get their water or they go out of business, substantially reducing overall US production of grain, cotton, fruit, and vegetables. The farmers warn that it is consumers who would pay the bill through higher food prices for shutting off the irrigation water.
No shutoff is imminent. But there already is a gradual closing of the faucet at a time when farmers want to expand irrigation to help ensure uniform crops from year to year.
Several hands are helping close the irrigation faucet:
* New awareness of limited supplies has made areas with water more possessive , less willing to share.
* Higher energy costs have sharply raised the cost of pumping or piping water.
* Declining levels of underground supplies add further to the pumping costs and reduce the flow.
* Irrigation's critics favor the one-time cost of moving farming to where the water is rather than the endless expense of shipping water to deserts.
The last point may prove the toughest one. It pits the costconscious Carter administration against politicians with their eyes fixed on the jobs, construction contracts, and votes traditionally generated by dams, reservoirs, and pipelines.
But even the politicians today are bending to the growing "ownership" feeling. The major Oahe project in South Dakota, championed by Sen. George McGovern (D), is being stalled by local opposition. Despite the $540 million it would bring to the state, more and more local interests favor smaller, cheaper projets to use the water where it is rather than paying to ship it hundreds of miles away.
Giant water-diversion projects to enrich Kansas and Texas farms with South Dakota water would be technically feasible, according to Kansas Geological Survey hydrologist Thomas McClain, who is working on a US Department of Commerce survey of water in the High Plains area. But he feels that such diversion has become politically impossible due to the high costs involved and the increasing local objections to relinquishing water rights.
Still, there are ways to get water without relying on huge federal projects -- at least in the short term.
Prof. Leslie Sheffield, farm management specialist at the University of Nebraska, reports that Nebraska farmers are adding to their 7.2 million acres of irrigated land at the rate of 300,000 acres a year. He sees a steady increase in the Rube Goldberg-style center pivot sprinkler systems, which creep in giant circles around 160-acre fields, even though each such system can cost $45,000, not including the cost of a well.
Nebraska is adding to its 65,000 wells and 20,000 center pivot systems, says Professor Sheffield, because irrigation pays. Corn yields for Nebraska over the past five years, according to US Department of Agriculture economist Verel Benson, have averaged 95.91 bushels per acre on irrigated land, compared with 26 .8 bushels per acre for dryland farming. That difference pays for the irrigation and will continue to do so, Professor Sheffield believes.
Despite such figures and arguments, Mr. McClain insists that "when the water begins to run out, as it is doing, then the farmers will be forced back to dryland farming." He and many others believe that pumping costs already are forcing more farmers to shut off their irrigation and switch from irrigated corn to dryland wheat.
Kansas Geological Survey scientist David Collins says that "basically, it's just a question of how long local areas want their water supplies to last for irrigation. Within 20, or 30, or 40 years, depending on local water use practices, farmers will have to go to dryland farming; they have no alternative."
But Herbert Grubb, director of planning and development with the Texas Department of Water Resources, is convinced there are alternatives -- and must be if America is to continue feeding itself and the world. He points out that yields are tripled on the 10 million irrigated acres in Texas -- which, he says, could be turned into 30 million highly productive acres with the addition of new large-scale water diversion projects.
Dr. Grubb estimates that irrigation over the next 20 years will draw down underground levels heavily in Texas, leaving only 55 to 60 percent of present supplies. He adds that due to high energy costs for pumping water, "we could price ourselves out of irrigation long before we run out of water."
But Dr. Grubb also points to a number of new techniques being developed in Texas to stretch out water. Special blades are added to cultivators to build tiny check dams in crop rows to hold water and help it penetrate the soil. Center pivot sprinkler systems are being fitted with hoses that cut down on evaporation losses and reduce pumping pressures needed. And more drought-resistant crops are being developed so that, for instance, a dwarf cotton plant can be harvested after a shorter growing season -- one therefore requiring fewer days of irrigation.
Texas, along with other Western states, also has studied the effect of carefully timed applications of irrigation water. The result: Corn today is being grown with half the amount of water applied by most farmers.
Whether such new developments will enable irrigation to expand or hold its own against dryland farming depends on many variables, including Organization of Petroleum Exporting Ccountries prices. So the experts cannot agree even on "a horseback guess." But no one doubts that irrigation is doing its best to resist a forced switch back to dryland farming.