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Lime alfalfa fields this fall for better yields next yearLime alfalfa fields this fall for better yields next year

Acidic soils can significantly affect alfalfa nutrient and water uptake. Lime applications can help.

Jennifer M. Latzke

August 17, 2023

2 Min Read
Overhead shot of alfalfa field
ADD LIME: Kansas State University experts advise Kansas farmers to make sure to apply lime to acidic soils now before planting their alfalfa this fall to ensure healthier stands and better yields.Digi4 /Getty Images

Some Kansas farmers may be contemplating planting alfalfa this fall. But they may be forgetting a crucial step for giving that alfalfa stand a good start.

Dorivar Ruiz Diaz, Kansas State University professor of soil fertility and nutrient management, reminded growers that acidic soils — like those in some parts of Kansas — can affect alfalfa’s nutrient uptake.

“Acidic soils can significantly reduce nodule establishment and activity in alfalfa, affecting nitrogen status and overall nutrient and water uptake,” Ruiz Diaz explained in the Aug. 3 Agronomy eUpdate, adding that the time to correct that with an application of lime is before seeding.

The first step is to test your soil to measure the current pH. K-State recommends, in general, areas east of the Flint Hills in Kansas should receive a lime application if the soil pH drops below 6.4, with a target of bringing the pH to 6.8. West of the Flint Hills, a lime application is recommended for soils with a pH of 5.8 or lower, with the target of a final pH of 6.0 after application.

“East of the Flint Hills, especially south of the Kansas River, the subsoil tends to be more acidic,” Ruiz Diaz explained. The higher target pH is there to make sure that the root zone has an adequate pH, as well as sufficient calcium and magnesium.

Soils to the west in general have more basic or high-pH subsoils that have enough calcium and magnesium to meet the crop’s needs.

And remember, soils with more clay or higher organic matter content will require more lime to reach the target soil pH than sandy soils.

Material selection

Ruiz Diaz gave these additional tips for farmers:

  • The finer the lime particle size, the greater the surface area of the product, and thus, the faster it will react and lead to acid neutralization in your soil.

  • Research shows 1 pound of effective calcium carbonate (ECC) to neutralize soil acidity is effective. It can be ag lime, pelletized lime, water treatment plant sludge, fluid lime or other sources, because they are all equal in neutralizing soil acidity.

  • The best results come from applying and incorporating lime into the soil, so it has time to react and neutralize the acidity before planting. Once an alfalfa stand is established, you’re limited to surface applications, which in general only affect the top 2 to 3 inches of soil.

  • Lower rates of lime application are recommended for no-till or reduced-till systems, to avoid over-liming the surface 2 to 3 inches of soil, since incorporation isn’t possible. Over-liming can reduce micronutrient availability.

With the cost of seeding a stand of alfalfa and the expectation that the stand will be in production for several years of hay crops, it’s worth taking the time to get the lime right. Read more in the K-State publication Soil-Test Interpretations and Fertilizer Recommendations online.

Source: Kansas State Agronomy eUpdate contributed to this article.

About the Author(s)

Jennifer M. Latzke

Editor, Kansas Farmer

Through all her travels, Jennifer M. Latzke knows that there is no place like Kansas.

Jennifer grew up on her family’s multigenerational registered Angus seedstock ranch and diversified farm just north of Woodbine, Kan., about 30 minutes south of Junction City on the edge of the Kansas Flint Hills. Rock Springs Ranch State 4-H Center was in her family’s backyard.

While at Kansas State University, Jennifer was a member of the Sigma Kappa Sorority and a national officer for the Agricultural Communicators of Tomorrow. She graduated in May 2000 with a bachelor’s degree in agricultural communications and a minor in animal science. In August 2000 Jennifer started her 20-year agricultural writing career in Dodge City, Kan., on the far southwest corner of the state.

She’s traveled across the U.S. writing on wheat, sorghum, corn, cotton, dairy and beef stories as well as breaking news and policy at the local, state and national levels. Latzke has traveled across Mexico and South America with the U.S. Wheat Associates and toured Vietnam as a member of KARL Class X. She’s traveled to Argentina as one of 10 IFAJ-Alltech Young Leaders in Agricultural Journalism. And she was part of a delegation of AAEA: The Ag Communicators Network members invited to Cuba.

Jennifer’s an award-winning writer, columnist, and podcaster, recognized by the Kansas Professional Communicators, Kansas Press Association, the National Federation of Presswomen, Livestock Publications Council, and AAEA. In 2019, Jennifer reached the pinnacle of achievements, earning the title of “Writer of Merit” from AAEA.

Trips and accolades are lovely, but Jennifer says she is happiest on the road talking to farmers and ranchers and gathering stories and photos to share with readers.

“It’s an honor and a great responsibility to be able to tell someone’s story and bring them recognition for their work on the land,” Jennifer says. “But my role is also evolving to help our more urban neighbors understand the issues our Kansas farmers face in bringing the food and fiber to their store shelves.”

She spends her time gardening, crafting, watching K-State football, and cheering on her nephews and niece in their 4-H projects. She can be found on Twitter at @Latzke.

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