Taken from the March 12, 2013 Colorado Economics Brief: Using Hay and Fertilizer Prices to Determine the Cost Effectiveness of Fertilizing Meadow Hay
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High elevation hay meadows are an important forage resource in the intermountain west. For many producers, meadows are the year-round hay and late season forage for their livestock. Fertilizing meadow hay to maximize production is an important decision that should consider the cost of inputs and production potential.
 
High elevation hay fields are often constrained by a short growing season, seasonal flooding and organic soils. The cost effectiveness of a nitrogen program needs to consider fertilizer cost, expected productivity gains and the value of forage.  Nitrogen use efficiency can vary, but 20 lbs of increased forage per lb of applied N is a safe assumption unless there is data indicating otherwise.

Guidance

• Consider if fields are organic or mineral soil type. Mineral soils will generally respond better to N applications.
• With the high price of fertilizer this year, producers need to carefully consider the cost effectiveness of fertilization.
• Do not assume higher N use efficiency, unless there is yield data to support this assumption.
• Fertilizer price is an key variable but hay value equally as important.

Other Considerations

• There is a variable correlation between spring or fall application of nitrogen and yield response. Preferred timing is site specific. Producers should consider fertilizer prices, field conditions and the potential for leaching before deciding on the time of application.
• Use soil tests for P, K and S determinations. Phosphorous may be an important component of a fertility needs, especially if clover is present in the meadow . Some P may already be part of commercial fertilizer mixes. Soil tests and a pH determination should be used to determine if a targeted P application is necessary.

Fertilizer Cost Calculator | Department of Agricultural and Resource Economics

Resources

• Brummer, J.E. & J.G. Davis. 2009. Fertilizing Mountain Meadows. Colorado State University Fact Sheet #535. Fertilizing Mountain Meadows - 0.535 - Extension
• Horn, Blaine. 2010. Nitrogen Use Efficiency of Cool-Season Perennial Forage Grasses Planted With and Without Alfalfa Under Irrigation for Hay Production. SARE Project # FW08-307. Final Report for FW08-307 - SARE Grant Management System