Most pastures in Iowa would benefit from improvement practices. Fertilization is commonly used as an improvement practice, but most pastures would benefit from having an additional kind of grass or legume added to what is already being used, says Steve Barnhart, Iowa State University Extension agronomist.
Adding additional species is often called oversowing or interseeding, he explains. Late winter through early spring is probably the best time to improve pastures with oversowing or interseeding. Spring soil moisture conditions are usually optimum for seedling establishment, and the competition from the existing pasture sod and weeds is minimal.
Legume nitrogen can help reduce need to buy fertilizer nitrogen
The forage species most frequently used in these pasture seeding efforts are red clover and white clover, notes Barnhart. The high nutritive quality of these legumes improves the forage quality of the pasture as a whole. Being legumes, their "nitrogen fixing" capabilities can be an economical strategy as well.
Providing legume nitrogen can lead to reduced fertilizer nitrogen needs for the pastures, he adds. A third, and often overlooked, advantage of including legumes with grasses in pastures is that mixed grass and legume pastures maintain more uniform production through the warmer summer months, when many of our cool-season pasture grass components exhibit summer dormancy.
Including grasses that are more productive is also good idea
Including grasses that are more productive can also improve many pastures, says Barnhart. With some thought, an additional grass species may significantly improve pasture production during the summer or fall months, compared to that of the existing pasture species mixture.
Producers wanting to add to or improve the forage species in their existing pastures should consider using either the frost-seeding method in February and early March, or interseeding later in the spring months. Frostseeding and interseeding have been popular methods for introducing legumes into existing pastures. Interseeding is probably the better method of the two for planting new grasses into your pastures. Frostseeding and interseeding are discussed in more detail in an earlier Integrated Crop Management News article, Consider Frostseeding or Interseeding Pastures in the Spring.