If your soil’s pH is at 6.2 or lower, apply lime this fall for next spring’s alfalfa, suggests Bruce Anderson, University of Nebraska Extension forage specialist.
“Alfalfa grows best in soils with a neutral pH of about 7,” he says. In more-acid soils, alfalfa roots are less able to absorb soil nutrients. Acid soils can also keep the nodules on alfalfa roots – which convert nitrogen from the air into nitrogen the plants can use – from forming and working effectively.
Most sandy, low-organic-matter soils, as well as heavier ground tilled and fertilized with nitrogen for many years, have become acid. They need lime, Anderson says. “But some folks still gamble with their alfalfa and resist liming even when their own soil pH is down as low as 5.5 or even below 5,” he exclaims.
Those who do decide to lime should know that it takes time for lime to neutralize acidity. “I recommend applying lime at least four months ahead of planting alfalfa. That means that, if you expect to seed a new field of alfalfa next spring, add lime as needed this fall to give it time to work. Sure, it costs money, but it's much less costly than having a stand failure or several years of low alfalfa yields.”
With this year’s early harvest, growers should have plenty of time to take soil tests, apply lime and till the soil to work the lime in, Anderson says.
“Maybe some folks just like to gamble, but me, I prefer to bet on a sure thing and invest in lime rather than a long shot.”