# Making Manure and Fertilizer Equivalent Calculations Easy

## Free Manure Valuator App helps calculate manure's value to value of inorganic inputs

##### Published on: Dec 13, 2013

Manure is valuable, but how valuable? It's a question that many farmers and ranchers have considered – probably more than once or twice. But a new smartphone app is ready to take the guesswork out of the answer.

Often, farmers and ranchers need to estimate the value of manure as a nutrient source to determine how much or what kind of manure can be substituted for inorganic fertilizers.

The Manure Valuator app, designed by the University of Arkansas Division of Agriculture, does just that: it calculates the dollar and nutritive value of manure applied to a specific field. Then, it shares the results via email.

The app was developed by Dharmendra Saraswat, UA associate professor and extension engineer and Karl VanDevender, a professor and extension engineer, both in the Department of Biological and Agricultural Engineering.

According to a UA announcement, the app is based on a simple premise that the monetary value of manure is linked to the market value of the inorganic nitrogen, phosphorus and potassium fertilizer that the manure is replacing. This means the value of manure depends largely on the crop's NPK fertilizer recommendation, the manure NPK content, and the amount applied.

The app allows the user to enter the cost of his or her local commercial fertilizer source on either a dollar per ton or dollar per pound basis. If dollar per ton values are entered, the app converts them to dollars per pound of nitrogen, phosphorus, and potassium.

The user then enters the crop’s NPK needs, ideally based on a recent soil test recommendations available through the farmer or rancher's local Extension Office.

The user then selects one of 18 different choices of dry and liquid manure. If desired, the default NPK values can be modified to better reflect the manure to be applied.

After the desired manure application rate is entered the app calculates the NPK fertilizer replacement value for the specific field crop based on NPK recommendation, manure source, and manure application rate. At this time any input value can be modified to evaluate the impact on the resulting calculated values.