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Crop Nutrition

Hay Fertilization – Simple Guidelines to Better Productivity and Profitability

Robert Mullen, Ph.D.

Robert Mullen

Robert Mullen, Ph.D.


Director of Agronomy

To say Dr. Robert Mullen is passionate about agriculture would be an understatement. He holds a Bachelor of Science degree in ag business from Cameron University, along with a Master of Science degree in plant and soil science and a Ph.D. in soil science from Oklahoma State University. In addition, Dr. Mullen has been published in a variety of scientific and trade journals. But it’s not just his academic accomplishments that make him unique. It’s his unwavering ability to take complex data and — in simple terms — explain how it impacts a farmer’s bottom line. Dr. Mullen delivers the kind of insightful observations that can lead to a more profitable business. As a leading agronomy expert, Dr. Mullen has a goal to further educate farmers on best management practices that improve their yields and maximize their return on investment.

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There have been several articles published the last couple months on managing nutrient inputs for hay production. The articles are available here: University of Georgia, Iowa State University, Ohio State University

While rate recommendations are specific to weather, species, soil type, etc., there are some general guidelines that should be considered universally. 

  • Soil test. This specifically applies to managing pH and making phosphorus and potassium decisions. Soil testing does not have to occur every year, but once every two to three years to track changes in nutrient status is usually recommended.
  • Split applications. Nitrogen applications should be split throughout the growing season. In some areas (usually higher rainfall/coarser textured soils), nitrogen application after each cutting is appropriate, and in other areas (lower rainfall/heavier textured soils), nitrogen application can be split between early spring, mid-summer, and early fall. Potassium applications can also be split. Typically, recommended splits should occur between early spring and early fall (rates being dictated by soil test or crop removal). Where rainfall or growing season is insufficient to promote forage regrowth, split applications or in-season nutrient applications between cuttings are likely of limited benefit.         
  • Make good estimates of yield. Since testing does not usually occur every year, tracking nutrient removal can be used as a guide for making rate decisions. Hay production removes significant amounts of potassium and phosphorus and that should be accounted for when thinking about application rates.

Just like any other crop, the goal of hay fertilization is to ensure adequate nutrient availability to support higher yields. Using these simple guidelines can go a long way to improving hay productivity and profitability.