Liming May Alleviate Alfalfa Seedling Problems

Liming May Alleviate Alfalfa Seedling Problems

September 12, 2008

When alfalfa seedlings are getting off to a slow start, low pH soils may be to blame. To avoid this problem, test soils before planting and amend as necessary.

Alfalfa grows best in soils with a neutral pH of about 7. When soils are acid, with a pH of 6.2 or lower, alfalfa roots are less able to absorb soil nutrients. The nodules that convert nitrogen from the air into nitrogen the plants can use have difficulty forming and working effectively in acid soils.

Most sandy, low organic matter soils and heavier soils that havebeen tilled and fertilized with nitrogen for many years are likely acidic. These soils need lime, but it's not a quick fix. It takes time for lime to really neutralize much acidity. Apply lime at least four months before planting alfalfa. If you expect to seed a new field of alfalfa next spring and soil tests indicate an acid soil, add lime this fall to give it time to work.

The lime application can be costly, but it's cheaper than having a stand failure or several years of low alfalfa yields.

Bruce Anderson
Extension Forage Specialist