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Vol. 17, No. 2
Article 6 of 10
February 20, 2007
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Frost-Seeding Legumes into Missouri Pastures By Craig Roberts February is an ideal month for frostseeding in Missouri. The ground is still frozen in February, making it easy to drive over the field without getting stuck or causing ruts. Also, the ground is often covered with snow, which marks tire tracks during seeding. Finally, February occurs right before the repeated cycles of freezing and thawing, a process that can pull seed slightly below the soil surface as the soil expands and contracts. In Missouri, the three most common forages to frost seed are legumes, namely annual lespedeza, red clover and white clover. These three legumes are seeded into tall fescue, the predominant pasture grass of Missouri. If seeded as the only legume, annual lespedeza is seeded at a rate of 10 lbs. pure live seed per acre. White clover is seeded alone at ½ lb or pound, and red clover is seeded at 6 lbs. There are two major factors that affect the success of frost seeding legumes, both during establishment and in seedling expression in a grass pasture. The first is residue. If the grass pasture has been grazed hard, it will have minimal amounts of thatch residue. If it has not been grazed hard, it is likely to have too much residue. This residue forms a thatch that suspends legume seed above the soil, thereby preventing effective germination. In these cases, pastures can be grazed lightly to "hoof in" the seed. A second factor is fertilization, and this factor comes into play after germination. Assuming legumes germinate effectively, they can be crowded out if the fertilization plan favors the grass. If a pasture is nitrogen fertilized in the early spring, it will encourage grass growth to the point of choking out the legumes. Below are data collected by McGraw and Kallenbach in Missouri. The data show that spring N applications reduce the amount of annual lespedeza in a tall fescue pasture in August. As a rule, only 25 lb/acre of N should be applied in spring if legumes are desired. If more N is applied, producers must be sure the pasture is grazed hard enough to prevent a grass canopy forming over the legumes.
Craig Roberts |
