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Irrigate Alfalfa Early and Late to Reduce Water Use

Alfalfa can be a hog when it comes to consuming water. So what can you do to produce maximum alfalfa yields when withdrawal restrictions limit the amount of water you can apply?

The solution is watering when alfalfa is most productive, which is during the first and possibly second cuttings, says Bruce Anderson. “This could mean irrigating even before first cutting if rainfall is sparse during spring,” the University of Nebraska forage specialist says.

Anderson says alfalfa uses water most efficiently during spring growth. At this stage, it requires only 4 to 5 acre-inches per ton of hay produced.

By midsummer, though, the crop takes 7 or 8 inches to produce a ton. By fall, that usage can drop back to 5 or 6 inches per ton.

If anything, Anderson urges you to avoid irrigating alfalfa in the heat of summer when water-use efficiency is at its lowest. 

“Apply most of what is left of an allotment after temperatures cool down later in the season year,” he says. “You might want to modify timing a little, though, to avoid having hay ready to cut near the end of September while it is winterizing.

“If you must decide on spreading water lightly across all acres or using heavier rates on fewer acres, I recommend heavier rates on fewer acres,” he says. “The first couple inches you apply just keep plants green without growing. Once this maintenance moisture is met, the rest of the irrigation produces growth.”

A solid strategy is to use your best land for irrigation, “because that’s where plants will respond best to extra water,” he notes.

irrigator network saves 114 billion gallons per year

Seven years of work by Suat Irmak to provide new technologies for irrigation management have steamrolled to the point that the University of Nebraska engineer has over 1,100 farmers participating in his programs. Combined, the water those producers save with advanced water-management efforts has reduced the amount of irrigation withdrawals by 114 billion gallons annually. That’s enough water saved to supply a city the size of Tucson, Arizona, for a year.

Irmak’s work is supported, in part, by NIFA Hatch and Smith-Lever funds. In the future, he’ll work to improve nutrient management and soil quality. He’ll also review the cost-benefit analysis of protecting the environment – always with an eye on improving farmers’ profits. 

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