Manure produced by confined livestock operations is being viewed differently today than it has in the past. Formerly, manure was looked at as a waste material and disposed of without much consideration for the nutrients contained in the material. Today, with environmental regulations becoming ever-more restrictive and the price of agricultural inputs on the rise, manure is considered a more viable nutrient source for crop growth and development.
For livestock operations that confine 1,000 animal units or more, there are federal guidelines for manure management regulated by the Environmental Protection Agency. These regulations were promulgated as a result of the Clean Air Act and require that these federal-sized operations land-apply manure at agronomic rates. It is not uncommon for these large operations to have a limited land base for the management of manure produced by their operation. Subsequently, manure needs to be exported and applied by nearby landowners. If the producer and the landowner both understand the value of the manure, it can be maximized as a nutrient source for growing crops.
If a manure sample is collected and analyzed for nutrient content, this information can be used to determine the monetary value based on current commercial fertilizer prices. In the summer of 2008, when commercial fertilizer prices peaked, manure nutrients could be valued anywhere from $2 to $10 per ton for nitrogen and nearly double that from a phosphorus perspective. Manure storage and handling as well as animal type and feed rations lead to variability in these estimates from one facility to another.
Customarily it is not reasonable for a producer to expect this much return on the manure. Factors to consider when determining the economic value of manure might include the following: nutrient availability, hauling and spreading costs, organic matter additions, micronutrients and weed seed content.
Nutrients contained in the manure may not all be available to the plants immediately following application. According to the Natural Resources Conservation Service, Agricultural Waste Management Field Handbook, approximately 45 percent of the organic nitrogen in manure will be converted to the plant-available nitrogen form within the first year after application. Additionally, there may be up to 50 percent volatilization loss from the ammonium-nitrogen fraction of the manure. The phosphorus portion is mostly available following application, and as a result tends to be the most limiting nutrient when agronomically applying manure. Even though there are some nutrient losses and availability concerns to consider when pricing manure, it still may be a more affordable nutrient source than commercial fertilizers.
Hauling and spreading costs have increased with the cost of fuel. Livestock producers hoping to market their manure need to factor this into the fee charged for the product. Consideration should be given to the distance that the material is being hauled and what percentage of the manure is water content. It may be advantageous for the producer to incorporate a drying or composting period prior to transporting. This will enable manure to be hauled a greater distance, thus maximizing export options. In order to make the manure more desirable for neighboring landowners, livestock producers should consider discounting the manure for hauling and applying costs incurred by the neighboring landowners as part of the advantage of manure use.
The addition of organic matter and micronutrients is most of the time overlooked when determining the economic value of manure. Organic matter can improve soil structure and water-holding capacity. Manure can be a good source of micronutrients such as zinc, sulfur and chloride as well as many others.
These additions are both positive for the soil system as well as crop growth. It is not easy to place a dollar figure on organic matter additions, and it can be difficult to determine the value of the micronutrients, but they should be considered when trying to promote the use of manure.
A concern by many landowners is the weed seed content of manure. Similar to organic matter and micronutrients, this is not something that is easily quantifiable. Although manure is likely to contain some weed seeds, landowners using manure as part of their farming operation may combat the issue most of the time with their existing herbicide program. Composting manure prior to land application may also help reduce the amount of weed seed contained in the material. Weed seed may be a disadvantage, but it can be managed if taken into consideration when using manure as a nutrient source.
With commercial fertilizer prices on the rise and environmental regulations forging ahead, livestock manure should be noted as a valuable nutrient source. It is not unreasonable to place an economic value on this type of nutrient source, but consideration should be given to factors that impact the content and application of the manure. ANM
Agronomist for Kansas Livestock Association Environmental Services