Is There Clover In There?  Getting the Most Out of Your Soil Tests


If you have sent a pasture or hay soil test through your MU Extension, you’ve been asked what kind of forage you have. Next time, before you answer, think about whether you have a legume in there and how much of it there is, or do you want to add a legume.  These things make quite a difference in the fertilizer and lime recommendation.

A soil test recommendation for a legume/grass mix, assumes that you have at least a 25% legume stand.  If you have less, your nitrogen recommendation may not be enough for good grass growth. If you are going from straight grass to legume/grass mix, you will have to cut your nitrogen application and sacrifice some grass yield that first year to get your legume established. In this case, use the overseeding recommendation on your test. This will recommend a little nitrogen and not recommend a potash amount that would hurt the seedlings. 

Legumes, like clover and lespedeza, add quality to the forage and provide most of the nitrogen that the field needs.  They also dilute the effect of the fescue endophyte fungus. Therefore, unless you are going for a fescue seed crop  or you are in the process of cleaning up your fields with some broadleaf herbicides, you probably want legumes in your field. 

If your soil pH and fertility are in good shape, the legume should provide the needed nitrogen. Lespedeza can handle a lower pH than red or white clover. A soil pHs below 5.0, lespedeza may be a better choice than clover until your lime application has time to work. If you want a legume, do not apply over 20 to 30 pounds of nitrogen, or the grass may crowd out the legumes. It is also best to have it closely clipped or grazed so the legume seedlings have adequate sunlight.

When someone is having trouble getting legumes to grow, the first two questions that should be ask are:

1. Is the soil pH and fertility inadequate for legume growth?

2. Is too much nitrogen being applied so, that the grass is crowding out the  legume?

A good soil test with the correct soil test codes should lead them in the right  direction to correct the problem.

For more information check out guides G4650, Establishing Forages  and G4646, Tall Fescue.  These are available on-line and at your local University of Missouri Extension Center. 

Source: Pat Miller, MU Extension Agronomy  Specialist