THE AMOUNT OF NUTRIENTS found in manure is influenced in part by the application method and timing.

High fertilizer costs, compared to prices before the COVID-19 pandemic, have made manure nutrients a valuable commodity. According to USDA’s Economic Research Service (ERS), commercial fertilizer costs per acre for growing corn in 2023 were almost 50% higher in comparison to 2006 to 2021 averages.

Row crop farmers, especially corn growers, can evaluate manure nutrients as an option when negotiating fertilizer purchases. Many livestock producers may have not considered the full value of manure nutrients, but these nutrients can potentially be a revenue source if viewed from the lens of opportunity cost.

Evaluate the manure

Manure nutrients can be compared to commercial fertilizer for the purposes of calculating the nutrient costs for lack of other nutrient opportunities. The DTN Retail Fertilizer Trends report for April 24, 2024, showed prices for anhydrous ammonia as $794 per ton, monoammonium phosphate (MAP) as $830 per ton, and potash as $513 per ton. This translates to $0.484 per pound of nitrogen, $0.696 per pound of phosphorus as P2O5 (excluding the cost of nitrogen included in MAP, which has 11-52-0 as common fertilizer composition), and $0.428 per pound of potassium as K2O.

The best case scenario for both the buyer and seller of manure is to agree on a nutrient analysis of safely collected representative manure sample(s). Nutrient costs can then be calculated using commercial fertilizer prices.

Let’s take an example of a liquid manure with a nutrient analysis from a certified laboratory of 50 units of nitrogen, 30 units of phosphorus as P2O5, and 25 units of potassium as K2O. The value of these three macronutrients in 1,000 gallons of liquid manure will be $55.78 using the retail prices listed above.

A goal of applying 200 units of nitrogen per acre for next year’s corn crop will mean that 4,000 gallons of this manure could potentially be used for a nutrient value of $223.12 per acre. This analysis does not include the cost of micronutrients such as sulfur and zinc, which are also present in manure.

A detailed, more expensive manure analysis can show concentrations of several micronutrients if requested from the laboratory. Similar analysis can be performed for other liquid manures (on a per 1,000-gallon basis) or for solid manures on a per ton basis. Variability in analysis is introduced by the type of manure (solid or liquid), storage methods, feed rations, bedding, and so forth. Nutrient costs as calculated above are an estimate — the main thing to remember is that manure is variable by its nature.

Manure application method as well as its application timing relative to crop planting also influences the amount of manure nutrients available for crop usage. For solid manures, not all the nutrients reported on a laboratory analysis are available for use by the crop in the first year after application. Surface applied manures have more environmental losses in comparison to injected or incorporated manures.

A short application window in spring prior to planting and compaction concerns have typically forced a majority of the manures to be fall applied. This, however, can subject manure-applied fields to inclement weather where some of the nutrients may be lost due to environmental conditions. Iowa State University Extension and Outreach publication PMR-1003, “Using manure nutrients for crop production,” goes into further details about nutrient usage and availability.

Know the rules

Manure application in most states is regulated; both livestock producers and crop farmers should verify manure application rules as these can create additional expenses. New fields in a manure management plan can add costs for regulatory compliance such as periodic soil sampling, calculating Phosphorus Index, and updating plans with acceptable manure application rates on eligible fields. Usable acres for manure application can potentially be different from total crop acres in each eligible field due to required separation distances associated with method and time of manure application.

Secondly, state departments of agriculture may regulate the sale of bulk animal nutrients in their respective state. For example, in Iowa, the sale of dry bulk animal nutrients requires payment of a per ton fee to the Department of Agriculture and Land Stewardship in addition to obtaining sale licenses, complying with regulations on being the producer or a distributor of manure, and adhering to requirements of land applying and stockpiling dry manure.

Both buyer and sellers of manure will need to learn such rules and work out the costs before agreeing upon the nutrient value of manure. Apply all manure in such a manner that no water quality violation occurs.

Both buyers and sellers of manure should also consider who will pay for the pumping or loading costs, transportation or trucking costs, and the field application costs including injecting or incorporating manure as regulated. These costs need to be agreed upon separately on a per-load basis or per-acre basis and may be used to adjust the nutrient value of the manure. Market fluctuation can cause labor costs, fuel costs, machinery costs, and so forth to change over time. A manure cost structure agreed upon between the buyer and seller in spring may not be the same in fall and vice-versa.

Lastly, it is an open market where supply and demand rules apply. In areas where manure is abundant, perhaps where there is a concentration of animal production facilities, some livestock producers may be willing to accept a lower price in exchange for guaranteed access to eligible fields for land application of manure. In contrast, if farmland is available abundantly in areas with only a handful of animal production facilities, access may be competitive for the crop farmers wanting to buy manure. In the end, valuing manure is a complex process and comes with several stipulations that must be considered when negotiating the value of manure.