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Kallenbach offers plans to manage drought stricken pastures

By Jean Caspers-Simmet
simmet@agrinews.com

Date Modified: 01/07/2013 1:58 PM

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ALTOONA, Iowa —The 2012 drought, which severely stressed pastures, is giving cow-calf producers the opportunity to see what is and isn't working.

University of Missouri Extension forage specialist Rob Kallenbach told farmers at last week's Iowa Cattlemen's Association annual meeting in Prairie Meadows Events Center to look at successes and pasture problems.

Kallenbach's presentation, sponsored by the Iowa Forage and Grassland Council, was part of the Cattlemen's College.

Farmers should evaluate desirable and undesirable plants, look at the vigor and density of desired plants and determine if there are periods of forage excess or shortage. Animal gains and reproductive performance should be considered.

Kallenbach's top picks for 2013, 2014 and 2015 are to add legume seed to most cool-season grass pastures, manage fertility inputs and prepare now to renovate the worst pastures next fall or spring.

Only add fertilizer when it pays for itself, Kallenbach said. Add little or no nitrogen in spring. Systematically invest in lime, phosphorus and potassium to promote desirable pasture species.

The benefits of including legumes are improved forage quality, fewer problems with tall fescue toxicosis and improved animal gains, reduced need for nitrogen fertilization and a longer growing season, Kallenbach said.

The downside is that legumes have higher fertility requirements, are more susceptible to diseases and insects, typically don't last as long as perennial grasses and are often considered "a pain" to keep in pastures, Kallenbach said.

Legumes can be frost seeded, broadcast or no-tilled into the pasture with or without herbicide.

"Overseeding is not a cure-all," Kallenbach said. "Success depends on the seeding depth, rate and date, soil fertility, competition from existing pastures species and moisture and temperature."

Many seeds will germinate but won't successfully establish if fertility is low, Kallenbach said. Soil pH is the most critical. If a test calls for lime, it must be applied six months before planting. Phosphorus and potassium are critical for legumes. Watch nitrogen fertilization of new seedings.

"It's a big mistake to put legumes in with nitrogen," Kallenbach said. "Grass has a competitive advantage and adding nitrogen when legumes are seeded makes it really difficult for them to grow."

In trying to control competition, grazing can be useful or detrimental depending on timing and severity. Burning is a good option if fuel is available. Burndown herbicide can help with no-till.

Kallenbach said to broadcast inoculated seed in February of every year or no-till in March to jump start legume stands.

Pasture fertility needs are complex, and before producers fertilize pastures they need to ask why they are doing it.

"Some good reasons to fertilize are if you expect good growing conditions and need additional feed, you want to change forage growth patterns to meet animal feed needs, you want to strategically use fertilizer to encourage one type of forage plant over another, or the cost to grow additional forage with fertilizer is less than it would cost to purchase more forage or additional feed," Kallenbach said.

Nitrogen, phosphorus, potassium and possibly sulfur are the nutrients most likely to show economic response, Kallenbach said.

When it comes to micro-blends or foliar sprays, Kallenbach said farmers should save their money.

"It's not a good economic decision," he said.

To maximize fertilizer dollars, focus on needed nutrients for desired species. Use soil testing information as a guide.

"You are only paying for fertility if it allows you to buy less feed or sell more animal live weight," Kallenbach said.

He recommends renovating pastures on 5 percent to 10 percent of the farm annually.