Getting the most out of your soil tests
If you've sent a pasture or hay soil test through your University of Missouri Extension Center, 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 if you want to add a legume, suggests a MU Extension agronomy specialist.
"These things make quite a difference in the fertilizer and lime recommendation," said Pat Miller.
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. Unless you're going for a fescue seed crop--yet a different soil test code and recommendation--or you are in the process of cleaning up your fields with some broadleaf herbicides, you probably want legumes in your field, Miller says.
"If your pH and fertility are in good shape, the legume should provide the needed nitrogen," she said. "Lespedeza can handle a lower pH than red or white clover. So if your pH is below 5.0, lespedeza may be a better choice than clover until your lime application has time to work."
If you want a legume, don't apply more than 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 enough sunlight.
"If you get a soil test recommendation for a legume/grass mix, it assumes that you have at least a 25 percent legume stand," Miller said.
If you have less, your nitrogen recommendation may not be enough for good grass growth, she continued. 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.
"If someone tells me they have trouble getting legumes to grow, my first two thoughts are that the soil pH and fertility are inadequate or they are applying too much nitrogen and the grass is crowding out the legume," Miller said. "A good soil test with the correct soil test codes should lead them in the right direction to correct the problem."