Still Time to Start Prepping for Pasture Renovations in 2021

November 4, 2020 1:59 PM
Blog Post

After the drought this past year, some pastures may benefit from a renovation in 2021. Proper planning and preparation are needed to successfully improve pastures with either a late winter frost seeding or no-till renovation with interseeding next spring. This ICM Blog post will discuss what you should be doing now to prepare for pasture renovations in 2021.

Address soil fertility needs. To improve the success of frost seeding or interseeding, adequate soil fertility is important. To know what the soil fertility levels are, you need to take soil samples for testing. Ideally soil samples would be taken this fall prior to any seeding next year to determine lime, phosphorus, and potassium needs. More information on soil sampling and testing can be found here.

  • From a pH perspective, a soil pH of 6.0 is recommended for grass, clovers, and birdsfoot trefoil and for alfalfa a soil pH of 6.9 is recommended. Ideally lime would be applied a year before seeding. Liming recommendations can be found in Table 16 in the ISU publication PM1688: A General Guide for Crop Nutrients and Limestone Recommendations in Iowa. Note that if placing lime on the soil surface with no incorporation, follow the 2 to 3 inch lime recommendations in Table 16.
  • Adequate phosphorus and potassium are also important to improve establishment and production. Use soil test results to determine if phosphorus and potassium levels are adequate or if levels are low and it would be beneficial to apply some fertilizer to bring up those levels.
  • Do not apply early season nitrogen to frost seeded or interseeded areas in order to minimize early season growth and competition from weeds and already established plants in the area.
  • More information on fertilizing pastures can be found in the ISU publications: PM1688: A General Guide for Crop Nutrients and Limestone Recommendations in Iowa and PM869: Fertilizing Pasture.

Control problematic weeds. If you struggle with thistles or other broadleaf weeds, be sure to get them under control before adding a legume to a pasture or hay stand. Fall can be a good time to control these problematic weeds.

Although we are now in November, the warmer weather this week will provide a great opportunity to complete any final weed management needed. Remember that ideally herbicide applications should be made when the sun is shining and daytime temperatures are above 50-55 degrees Fahrenheit. Before spraying, do check the weeds present to make sure they still look healthy enough to spray.

If you use a herbicide to control weeds, do double-check crop rotational intervals on the herbicide label before seeding. 

Reduce current stand competition. Typically, over-grazing or mowing a forage stand short is not recommended. However, when it comes to frost seeding or interseeding into an existing stand, it is advised to over-graze or mow the stand short this fall. This will weaken the current stand, but it will help the new seeding to compete with the current stand next spring. Additionally, this helps to get better seed-to-soil contact.

More information on frost seeding can be found here, and more information on interseeding can be found here.


Meaghan Anderson Field Agronomist in Central Iowa

Meaghan Anderson is a field agronomist in central Iowa and an extension field specialist at Iowa State University Extension and Outreach. Educational programming is available for farmers, agribusinesses, pesticide applicators, certified crop advisors, and other individuals interested in...

Rebecca Vittetoe Field Agronomist in EC Iowa

Rebecca Vittetoe is an extension field agronomist in east central Iowa. Educational programs are available for farmers, agribusiness, pesticide applicators, and certified crop advisors.

Areas of expertise include agronomy, field crop production and management of corn, soybeans, and...