University of Nebraska Extension forage specialist says some of the hardest-hit alfalfa fields may require some fall irrigation to get moisture levels at least closer to normal.
Though it's not a typical irrigation time, taking the time and resources to do it now could make the difference between no crop and a good crop next year.
"Alfalfa in many areas may need more surface soil moisture to prevent alfalfa roots from drying out and dying over winter. Soil moisture also helps keep soil temperatures from dropping too low for alfalfa plants to survive," Anderson says in a university report. "Subsoil moisture also will be needed for top yields next year. During peak water use next summer, it can be impossible to keep up with alfalfa's water needs without a water reserve in the deeper root and soil profile. Irrigating now and until soils freeze can protect plants and improve yields."
Why do it now instead of waiting until next spring? Because it's cooler, you'll get more bang for your irrigation buck. And, you'll be able to boost the alfalfa plants' ability to go where they need to in order to get the water they need, both now and next year.
"One advantage to irrigating now is that evaporation is lower than in summer, permitting very high irrigation efficiency. Another advantage is in the alfalfa plant itself. Most irrigated alfalfa fields never get much water below 4 feet deep, but alfalfa can develop roots down 8 feet or more," Anderson says. "You waste some of the water collection ability of alfalfa by not building water reserves below 4 feet. Don't waste this ability. That water reserve will keep your alfalfa growing rapidly during next summer's heat and allow you to irrigate on a more timely basis.
"Since many alfalfa soils have low water infiltration rates, irrigating now may be the only time you can build that water reserve," he adds.
