What Is Manure Worth?

By Erin Cortus

With the cost of fertilizer increasing, the manure produced by a livestock operation is often considered an additional source of income for an operation, rather than an expense. Putting a dollar value for manure can also help in decision-making for manure transactions and livestock expansions.

What is manure worth? Most manure is applied as a fertilizer on cropland, so from that perspective a reasonable way to value manure is to look at what would it cost to buy the commercial fertilizer that would have been needed if the manure were not available. With this method, you give value to the manure nutrients that meet the needs of the crop, but do not provide credit for excess nutrients. Further considerations this method can include are application cost differences, nutrient carryover to subsequent years, manure nutrient availability and yield boost associated with the organic matter in manure.

How do I calculate how much the manure is worth? The gross nutrient value of the manure is the nutrients needed by a crop multiplied by the nutrient costs. For example, a soil test for a field and given crop indicates a need of 180–60-55 (for N-P-K, in lbs/acre). If current fertilizer prices are $0.44/lb N, $0.36/lb P2O5 and $0.41/lb K2O, the gross fertilizer nutrient value is:

(180 lb/acre x $0.44/lb) + (60 lb/acre x $0.36/lb) + (55 lb/acre x $0.41/lb) = $123/acre

The calculations for valuing manure accurately are more complicated than that, however, because if manure application results in more N, P, and K going on than the crop actually needs, we only value the nutrients that are needed and would have been purchased as commercial fertilizer. Nutrient availability also needs to be considered, and application costs need to be subtracted to arrive at a net value of the manure.