Soil School: Feeding alfalfa for healthy soil and higher yield

(Kara Oosterhuis/RealAgriculture)

The soil health benefits of growing a forage crop, such as alfalfa, are well documented.

Traditionally a staple crop on livestock farms, alfalfa delivers increased biomass, especially in its root structure where the plant boasts a large tap root which contributes to soil health, while reducing compaction. There’s also increased organic matter and water-holding capacity, more biodiversity, and better nutrient cycling — all contributing to healthier, more productive soil.

But is it possible to feed alfalfa to even further increase soil health and yield? On this episode of RealAgriculture’s Soil School, Mosaic technical sales manager Aaron Stevanus shares how alfalfa responds to fertility and what that means for the soil and a grower’s bottom line.

In the video, Stevanus looks at a research trial that compares different levels of fertility in alfalfa. He notes that livestock producers generally feed the crop with manure but when additional nutrients are applied to the field, biomass and economic yield is increased. (Story continues after the video.)

In the trial, an untreated check was compared to side-by-side, replicated plots that added additional potassium, boron, magnesium, and sulphur. As the elements were progressively added to the crop, yield increased; the untreated check in the trial averaged 6.87 tons/ac on three cuts compared to 8.32 tons/ac for the full fertility package.

Stevanus concedes that the additional fertility adds crop input cost, but he notes trial analysis does indicate there is positive return on investment (ROI) for the grower. When muriate of potash was added, the trial showed an ROI of $17.81 per acre; with the addition of boron, the return grows to $43.31; and when magnesium and sulphur are included, the payback is $48.13 per acre.

“At the end of the day, we have healthier soils, better yield and better crops,” says Stevanus.

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