March 11, 2016
You are probably a month or more away before you think about using pastures for grazing unless you stockpiled some forage, or left extra grass ungrazed last fall. Usually the first thing you will do to improve your pastures is to fertilize them in the spring... but fertilizer isn’t cheap. Wouldn’t it be great if there was a way to improve the productivity of your pastures without the cost of commercial fertilizers?
Actually there is a way you can accomplish this... and it’s the time of year to do that. By adding legumes such as clovers, alfalfa, birdsfoot trefoil, or other legumes to your pasture mix, you will improve the quality of the forage. And since legumes add nitrogen to the soil, you also reduce your need for fertilizer costs in years to come.
One point I should make before I go any farther is this is a good practice if, AND ONLY IF, you have thistles, leafy spurge, or other broadleaf weeds under control. It doesn’t make sense to add legumes if you have to broadcast spray your pastures to control these weeds. On the other hand, if you only cut a few thistles each year or spot treat small areas for problem weeds, then you’re ready to add legumes.
There are two ways to add legumes... frost seeding or interseeding. With frost seeding, you broadcast the seed on the snow-free fields during winter or early spring. Right now is an excellent time to frost seed if you can drive across pastures without tearing them up. The freezing and thawing of the soil as spring arrives helps work the seed into the ground. Results from frost seeding have been variable and usually requires you to increase your seeding rate by 50% to get a good stand.
A more reliable way to establish legumes in a pasture is to interseed them with a no-till drill. If you don’t have access to a no-till drill, many Pheasant Forever chapters have one you can rent. In Burt County, contact Quentin Connealy in Tekamah to rent the PF no-till drill. You can interseed once the frost has gone out and pastures are firm enough to drive on. One important consideration if using a no-till drill is not to plant the seed too deep. Legumes have small seeds and should be planted no more than 1/4 inch deep.
With either method of seeding, these pastures require special attention in the year you seed them. First, you should take a soil test and then fertilize for the legumes. Legumes need phosphorus and prefer a soil with a pH above 6.
The second thing you will need to do is reduce competition for the legumes in the year they are established. Overgraze the pastures before the legumes emerge. This slightly weakens the grass and makes them less competitive. Also, do not fertilize with nitrogen which stimulates the grass growth.
During the growing season you can use a technique called flash grazing. Whenever the grass gets 3-4 inches taller than the legumes, stock the area you seeded with legumes with enough cows or yearlings so they graze the area down to the height of legumesin one day. Then remove the livestock until the grass gets tall again and repeat the flash grazing. If the area you interseeded is too large to be grazed down in one day, you may need to run some temporary fencing to divide the area into smaller paddocks and move the livestock between these, one day per paddock.
Which legumes you use depends on the kind of pasture you have. Many area pastures are cool season grasses like brome or orchardgrass. In these pastures, a mix two pounds per acre each of a grazing type alfalfa, red clover and birdsfoot trefoil works well.
If you have warm season grass pastures like switchgrass, Indiangrass, big or little bluestem, or side-oats grama, or some combination of these grasses, you should lower the total seeding rate and not use alfalfa in the mix because it is too competitive for these grasses in the early spring. A mix of one pound of red clover and three pounds of birdsfoot trefoil per acre has worked well.
In any case, you want to be sure to add the appropriate innoculants to the seed so you have the nitrogen fixing bacteria in the soil by the plants to get the maximum benefit from the legumes. Legumes won’t add much nitrogen the first year, but by the second or third year, a good stand of legumes can cut in half the amount of nitrogen you’d normally use to fertilize the grass.
An additional benefit of adding legumes to your pastures is the amount of forage available to livestock. In a grazing trial we ran several years ago, we got about half again as many grazing days in those paddocks with legumes. For example if we got four days of grazing in a paddock that was just grass, we would get six days of grazing in a paddock of similar size and species of grass when there were legumes with the grass.
For more information on interseeding pastures with legumes, contact your local Nebraska Extension office.