By Stephen Barnhart, Department of Agronomy
Forage seedings can be made in the spring as soon as a suitable seedbed can be prepared. Spring seedings made after mid-May may not be as successful, due to rapid drying of surface soils.
Clear brush, fill gullies and take soil samples. Lime and fertilize according to needs shown by soil testing. For most efficient lime use, it is best to have needed lime applied and incorporated six months to a year before planting.
Destroy sod by shallow plowing or disking, followed by necessary secondary seedbed preparation operations. Seedbed firmness is very important. Using a cultipacker or roller on tilled seedbeds before planting is recommended. Another alternative is to use a non-selective herbicide to kill the old sod. Incorporate needed fertilizer before seedbed preparation, or surface topdress on killed sod sites.
Species and Variety Selection
Select species based on the desired use, persistence and tolerance to site conditions. The Iowa State University Extension publication Selecting Forage Species, PM 1792 covers characteristics of many forage legumes and grasses used in Iowa, and provides suggested seeding mixtures and seeding rates for various situations.
Seed in one of the following ways on a well prepared seedbed.
Use a grassland drill with depth-control and press wheels or a cultipacker-roller type seeder designed for small seeded forage legumes and grasses. Plant at a ¼ to ¾ inch depth.
Use a grain drill, equipped with small seeded forage boxes, as a broadcast seeder for small seeded legumes and grasses to prevent small forage seed from being planted too deeply. Cultipack or roll after seeding.
Broadcast seed onto a firm, tilled seedbed and cultipack or roll for shallow seed coverage and seed-to-soil contact.
Or, if planting into a killed sod, or un-tilled crop residue field, use a no-till drill, control seeding depth to no deeper than ½ inch, and adjust press wheels to provide good seed-to-soil contact.
On sloping sites — consider erosion protection
Where there is a risk for erosion on tilled seedbeds, one to two bushels of oats per acre or a reduced seeding rate of another spring cereal grain may be seeded with forage mixtures as a companion crop or cover crop. The cereal grain will serve first as erosion protection, but will increasingly become competition for the newly planted forages. The sooner the cereal competition can be removed, the quicker the new forage seeding will establish. Cereal companion crops may be grazed, cut for silage or hay, or harvested later as grain and straw with associated longer completion. Particularly in dry springs, removing companion crops as early as possible can conserve moisture for the new seeding.
Management After Establishment
For weed and competition control, graze new seedings rotationally or mow (clip) sequentially, during the first few months of the establishment to limit unneeded competition for light, moisture and plant nutrients. Developing seedlings will establish more quickly. Also avoid any cutting or grazing new seedings after early September to improve winter hardening.
For some mixtures or pure stands, selective pre-plant or post-emergence herbicides may be used in place of a companion crop. This option may only be appropriate on sites where erosion is not a risk. Seek help from your agricultural professionals when selecting and using herbicide for weed management in new forage seedings. Be sure to read and follow the label when using any agricultural chemical. Also take into account any harvest or grazing withdrawal periods called for.
Fertilize in later years according to soil test recommendations.
Graze rotationally and avoid over grazing to maintain ground cover and animal grains.
Remove grazing livestock and limit grazing for the last four to six weeks of the growing season to allow plants to adequately winterharden. Use management practices that retain adequate plant cover if cutting or grazing after fall dormancy.
For more information, see the following Iowa State University Extension publications - Selecting Forage Species, PM 1792 and
Steps to Establish and Maintain Legume-Grass Pastures, PM 1008.
Stephen K. Barnhart is the ISU Extension forage agronomist. He can be contacts by phone at 515-24-7835 or by e-mail at firstname.lastname@example.org.