University of California researchers have a novel idea: what if we dump more water on alfalfa and use that to recharge aquifers?
Over a six-week period in February, March and April, Dahlke oversaw a test in Siskiyou County in which 140 acre-feet of water were applied to 10 acres of alfalfa. That’s well over twice the amount of irrigation water the field typically gets in an entire year.
“It was just pouring into the ground,” Dahlke said.
The water percolated readily into the earth and the groundwater table in the vicinity of the farm rose quickly. Just as important: by June the alfalfa field that had been watered so heavily was just as healthy as a control plot. Alfalfa is known to “drown” if watered very heavily in summer months, but it appears that the winter dormancy of alfalfa is helping the crop to tolerate saturated soils for some time. Field trials near the UC Davis campus have corroborated the Siskiyou County results, Dahlke said, though additional tests in more soil types and warmer climates (e.g. the southern Central Valley) are needed.
The premise: recharge is good if you have the chance, but land set aside exclusively for the purpose is at a premium. But there’s plenty of alfalfa land where you could try this.
One more example of the adaptive capacity offered by the queen of forages.