All across New Mexico's arid breadbasket, the stunning prospect of limited irrigation water from low reservoirs has farmers anxiously puzzling over what to plant this spring.
A New Mexico State University expert says to expect more plantings of cotton, grains and short-season onions. Facing tougher times are water gulpers like alfalfa and pecans, and crops that are sensitive to poor-quality well water, like chile, lettuce and carrots.
“Planting decisions are going to have to be made fairly quickly,” said Denise McWilliams, an agronomist with NMSU's Cooperative Extension Service, who has been engulfed by calls from worried producers asking what viable alternative crops are out there on the agricultural landscape.”
Most of the crops in southern New Mexico are already planted by April or May.”
New Mexico should see more short-season, upland cottons being planted — probably 5,000 to 10,000 acres, she said. These cotton varieties use relatively little water and can tolerate poorer water quality.
Other alternatives are sorghum, millet, oats and other annual grain crops that can be planted for grazing and, later, harvest.
“Right now in southern and northeastern New Mexico, where limited irrigation is already a reality, people are also looking at short-season crops like onions,” she said. “The idea is to get them in and get them out and just leave the ground fallow.”
But in a state often plagued by billowing clouds of dust that could be a problem, since leaving the ground idle increases the likelihood of erosion.
Meanwhile, the lack of surface irrigation water from reservoirs has forced many producers to turn to little-used wells to get a crop in the ground, McWilliams said. The Elephant Butte Irrigation District reported that this season's initial water release will be a slim 4 inches, when the normal release is 2 to 3 acre-feet.
An acre-foot of water is enough to cover one acre of land a foot deep, or 325,000 gallons of water.
“The problem with this well water, particularly in southern New Mexico, is quality,” she said. “Since the water is being drawn from shallow aquifers, it tends to be high in salinity.”
As a result, the soil itself changes. Instead of clumping together, the soil particles are dispersed or pushed apart, which increases compaction and creates a crust on the land, McWilliams said. That limits water movement and hinders seed germination because the plants have difficulty breaking through the soil surface.
While alfalfa production is likely to dip this season, New Mexico's top cash crop, with a value of $161 million annually, should survive the season relatively unscathed, though with sharply reduced cuttings. According to the New Mexico Agricultural Statistics Service, the state's growers produced 1.45 million tons of alfalfa last year.
One reason for alfalfa's persistence lies in its ability to find water and withstand drought, McWilliams said. Alfalfa has very deep roots, usually more than 4 to 5 feet in depth. And when there's not enough water, the crop goes dormant until more moisture is available, she said.