The hog manure collecting in your lagoons or pits is more valuable today than ever. While it was always a useful resource, many pork producers now consider manure’s value a significant contribution to the facility’s cash flow.

Skyrocketing commercial fertilizer prices have certainly directed more attention your way, and your operation’s manure capture and application strategy can help determine how you mine this new black gold. Whether you are selling manure to crop producers or using the byproduct to fertilize your own corn crop, you need to determine a value for this hot commodity.

According to the Swine Waste Economical and Environmental Treatment Alternatives Web site, the nitrogen, phosphorous and potassium cost to fertilize 1 acre of corn rose from $121.92 in 2006 to $222.09 in 2008. The same dramatic increase in commercial fertilizer cost also influences the value of liquid manure.

Capturing liquid manure’s maximum value, however, is not automatic. So, how can you make sure you are getting the slurry’s full value?

Your nutrient-management plan is the place to start, and this means evaluating soil and slurry nutrient levels regularly. Matching the crop’s nutrient needs as closely as possible will maximize the manure’s value. If the nutrient level in the manure is higher than crop requirements, the excess is simply wasted.

For example, if slurry is applied in amounts targeted to supply 100 percent of a crop’s nitrogen requirement, both phosphorous and potassium will likely be over-applied. In that case, you will not get the most out of the manure, plus it may create crop and environmental problems such as reduced yield or nutrient runoff.

In the opposite case, if the manure falls short of the crop’s nutrient requirement, yields will suffer, as will the manure’s value. Reduced manure nutrient levels also reduce its value.

“Efficient use of nutrients in swine diets means that the total amount of nutrients entering the manure storage has decreased,” according to John Lory, environmental nutrient-management specialist and principal author of a University of Missouri soil-management bulletin. (See sidebar.) “In this case, producers who use the manure to fertilize their fields may lose money because they need to purchase more fertilizer to compensate for the lower nutrient levels in the manure.”

Maximizing manure’s value rests largely on maximizing the utilization of the nutrients it contains. If those nutrient levels don’t match your crop’s needs, the manure may be more valuable to another producer whose crop needs would better utilize what it offers.

It may be easiest, however, to get full fertilizer value for the manure by applying it to land under your control. “This allows you to substitute manure for fertilizer that you would have otherwise purchased, thus allowing you to get nearly full fertilizer value for the manure,” Lory says.

Another option is to use a combination approach. That involves applying manure at a lower rate than crop needs call for and then adding supplemental commercial fertilizer in the spring. This approach offers the potential for more acres to receive a yield and soil enhancement benefit from the manure. In this case manure value is increased.

A quick calculation shows the importance of properly utilizing manure’s nutrients to capture its full value. According to SWEETA, when slurry was applied to meet 100 percent of corn’s nitrogen requirements at 2008 prices, slurry had a calculated value of 3 cents per gallon. When slurry was combined with anhydrous ammonia and potash to meet nitrogen and phosphorous requirements, the 2008 calculated value rose to 9.56 cents per gallon.

This variation in manure value was illustrated in a research study titled “The Other Fertilizer,” conducted by Robert Koehler and William Lazarus, University of Minnesota. (See sidebar.) The study involved 15 pork production sites in 2005, 22 in 2006 and 10 in 2007.

When valued at projected fertilizer prices in early 2008, the study estimated manure’s value at three levels. It showed that manure value can depend on many factors, but the net value realized on these farms came in at a maximum of $95 per acre. The average was $37 per acre and the minimum was minus $23 per acre. “These amounts would be higher today with the increase in fertilizer prices that has occurred since early 2008,” Koehler adds.

Now let’s look at the phytase factor. The use of phytase in swine diets can adversely affect the manure’s value by reducing phosphorous levels. However, according to Koehler’s study, typical application rates of 3,500 gallons of swine finishing manure per acre will supply enough phosphorous even if the level of the nutrient is only 20 pounds per 1,000 gallons.

The study goes on to explain that “University of Minnesota-recommended P2O5 (phosphorous fertilizer) application rates for corn do not suggest more than those amounts unless soil test levels are in the low to very low range.” The study concludes that “many fields, especially those that have received manure in the past, should not be negatively affected (by the use of phytase in swine diets) and the feed-cost savings will not be lost in reduced fertilizer replacement value.”

Other important factors that influence manure’s value include application timing. “Ideally, manure is applied in spring, close to corn planting time,” according to Lory. “Spring applications reduce the potential for nitrogen loss between application and the time the crop needs nitrogen.”

The slurry’s water content is another significant value reducer. Water from drinkers, pressure washing or cooling sprinklers can reduce dry matter percentages in slurry, thereby reducing its nutrient levels.

“Producers should evaluate their management to avoid dilute manures unless other offsetting benefits are gained,” Lory says. “The economic value of dilute manure is significantly less due to hauling many more gallons to achieve the required crop nutrient levels.”

Measuring manure’s value is largely dependent on the value of commercial fertilizer it replaces. “The reality is that these numbers have been changing quickly,” Lory says. “Current fertilizer prices are around 75 cents per pound for nitrogen, $1.20 per pound for phosphate and 55 cents per pound for potassium. However, I suspect that nitrogen prices will ease somewhat, which should be expected because gas prices are falling too.”

Swine manure has long been under-valued as a pork production byproduct and as a soil amendment. While today it’s getting more attention, it may offer the greatest value to your operation as part of a combination fertilizer application program. This means a nutrient-management plan as well as regular soil and slurry nutrient testing play key roles in maximizing the value of this new black gold. PK

Slurry: A Fistful of Dollars

Manure’s economic value varies by the nutrients it contains and the utilization of those nutrients. John Lory, University of Missouri environmental nutrient-management specialist, suggests these keys to maximizing the value.

  • Rotate fields receiving manure from year to year.
  • Apply manure to cropland under your control, thereby reducing or eliminating the need to purchase commercial fertilizer.
  • Minimize the amount of water in the manure storage, which decreases the cost and time required for manure application.
  • Slurry manure is most valuable as a nitrogen fertilizer when it is injected into the soil as close as possible to the time that the crop will need the nutrients.

    “We recommend applying manure based on nitrogen need but then rotating manure application off that field until the excess phosphorous and potassium from the manure has been used by subsequent crops,” Lory says. “This maximizes the phosphorous and potassium value of the manure while allowing the producer to use manure as the complete nitrogen source in the year of application.”

To Find Out More…

Web site resources offer help and extensive information for determining swine manure’s value. They also can assist you in getting the most economic return for your operation. For management strategies and a spreadsheet, click here.

To access a University of Minnesota Extension bulletin, “The Other Fertilizer,” that outlines methodology for determining manure value and reports results of a three-year study of manure values as seen in Minnesota pork production systems, click here.

For SWEETA’s Web site and information on the value of liquid manure as a fertilizer for corn production, click here.

For a copy of “Optimizing Fertilizer Value of Manure From Slurry Hog Finishing Operations” by John Lory, University of Missouri, click here.