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The perennial puzzle: Deciding whether to fertilize your pasture in the spring

By the U of A System Division of Agriculture

FAYETTEVILLE, Ark. — For many producers in Arkansas, fertilization in the spring isn’t so much a tradition as it is a necessity, along with crop rotation and soil testing. For pasture managers, however, the decision of whether to fertilize a grazing area depends on several factors that can change from year to year.

SPRING MEANS 'NPK' — The decision whether to fertilize a given pasture each spring should be primarily based on soil testing results. (Division of Agriculture photo.)

Dirk Philipp, associate professor of forage agronomy for the University of Arkansas System Division of Agriculture, said that it all comes down to what your soil really needs.

“Fertilizer is an expensive input to livestock agriculture,” Philipp said. “The basis for the decision when and how much to apply is a regular soil sampling plan.”

At a minimum, Philipp said, soil samples should be taken every two years.

“Not only will this help producers fertilize pastures in a more targeted fashion, it also serves to record how much soil fertility changes over time,” he said.

The Cooperative Extension Service provides cost-free soil analysis. Arkansans can find their nearest extension office in extension’s online directory.

Once growers receive their results, Philipp said, they should carefully check the recommendations, particularly the pH balance of the soil as well as the potassium, phosphorous and nitrogen levels.

“It’s important to know the acidity of your soils,” Philipp said. “It’s no problem if it’s about 6.0 — many pastures are — but avoid letting it drop too low. Bringing it back up will take time and easily require a couple of tons of lime per acre.”

Likewise, pastures that have historically been fertilized with chicken litter won’t normally be phosphorous-deficient, but growers should try and keep their levels well within the normal range so that they have “room to spare” in changing conditions, Philipp said.

“Potassium is an important element for plant cell function and one that affects plant health and productivity immediately,” he said. “Unfortunately, it is also quite expensive to apply.”

Philipp encourages growers to keep adequate potassium levels in soil, so they don’t find themselves suddenly needing to make large investments in the nutrient.

“Both phosphorous and potassium can be applied in advance, so if you know how much might be missing, you can fit those in your budget better,” he said.

Nitrogen, Philipp said, is the most limiting nutrient for plant growth and should be applied right when it’s needed.

“Keep in mind that both cool and warm season plants grow most rapidly in spring because of increasing day length and temperatures,” he said. “They will substantially reduce their growth rates during fall due to decreasing day length and temperatures.”

Timely application is important, Philipp said, but can mean different things, such as:

  • Before a rain shower, when growers actually can get into the field

  • After a hay cut, when large amounts of nutrients are removed

  • At the beginning of the growing season, if a producer wants to apply a blend of all NPK

  • If poultry litter is available, depending on one’s timeline for cleanout and delivery.

“These are all valid compromises you may have to make,” Philipp said.

When it comes to linking fertilization with pasture management, producers may need to address an additional host of issues, he said.

“When applying nitrogen to tall fescue in spring, are you able to actually graze it off and avoid fescue toxicity as much as possible? You may be better off applying it in early September for stockpiling,” Philipp said.

“Some forages, such as orchardgrass, definitely need additional nitrogen to be productive, while tall fescue is less sensitive to skipping a year,” he said. “Native warm season grasses can do without nitrogen fertilization for a long time. Hay crops of any kind including summer annual forages require a fertilizer budget and should be planned accordingly.”

To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit www.uaex.uada.edu. Follow us on X and Instagram at @AR_Extension. To learn more about Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website: https://aaes.uada.edu/. Follow on X at @ArkAgResearch. To learn more about the Division of Agriculture, visit https://uada.edu/. Follow us on X at @AgInArk.

Another arctic air blast coming our way; Winter Weather Briefing from the NWS

Pockets of very light freezing rain are expected in portions of central and eastern Arkansas this morning. A light glaze of ice is possible in places. Amounts will be on the order of a trace to a few hundredths of an inch.  A Winter Weather Advisory has been posted. 

Another round of Arctic air will arrive Thursday night/Friday, and will stay with us through the weekend. The magnitude of this surge of cold air will not rival what we have experienced lately, but temperatures will be well below normal. Saturday will be the coldest day with temperatures starting to recover Sunday. 

As Arctic air exits to the east early next week, moisture will increase across the Plains. Rain will likely develop across the region on Monday, and may begin as a period of freezing rain in the morning. At this time, it appears some icing is possible, especially in western sections of the state.

National Weather Service Winter Weather Briefing for Arkansas

We are still on track to seeing some wintry weather over parts of northern and western Arkansas late today and tonight. Rain will mix with and eventually changeover to all snow by early this evening, across the Ozark and Ouachita Mountains. Snow accumulations of one to two inches remain possible, especially in the highest elevations.

While this will be a quick hitting event, there may be minor travel impacts. Roads in some areas may become snow/slush covered, with icy patches on bridges and overpasses.