What is it worth? The Economic Value of Manure Testing
Animal manure is a valuable fertilizer for crop production, but effective utilization requires knowledge of nutrient content. This warrants the manure be sampled and tested to make informed management decisions. However, there has been low adoption of annual manure testing (ca. 20%). Presumably, this is because farmers view the costs and efforts of testing to be greater than the benefits. To evaluate the monetary value of manure testing, a model was developed. Using published literature values of manure nutrient concentration and other agronomic factors as inputs, this model assesses how production expenses and incomes change with knowledge of the manureâ€™s nutrient content. The model suggests that when applying manure at a nitrogen-limited rate, sampling manure prior to application increases profits by $20 to $68 ha-1; sampling during application increased profits by $3 to $50 ha-1. When applying at phosphorus-limited rates, additional profits of $4 to $22 ha-1 were realized for both pre- and during application collected. These results illustrate that manure testing is economically beneficial and indicate that when application is nitrogen limited, manures should be sampled prior to manure application.