University of Maryland Extension

Organic Nutrient Value Calculator (ONVC)

To help quantify the value of manure, the University of Maryland Agricultural Nutrient Management Program has developed the ONVC. This calculator is designed to utilize current fertilizer prices to determine the value of the nutrients in a manure or other organic source. You'll have to do a little leg work by calling your local fertilizer dealer to determine current pricing.

The ONVC assigns value only to those nutrients required by the crop. For example, if the phosphorus (P) levels in the manure exceed crop requirements at a given application rate, the calculator will only assign value to the pounds of P required by the crop. Any P applied in excess will not be assigned a value. The theory here is that you would not purchase fertilizer nutrients in excess of your crop's needs; therefore, we should not assign a value to excess nutrients supplied by manure or other organic materials.

You will be asked to enter the organic analysis of your nutrient source, the crop requirements, and the recommended application rate of the nutrient source. The calculator will assign a value to the nitrogen, phosphate and potash supplied by the nutrient source. The ONVC also splits out organic nitrogen and ammonia nitrogen so that you can evaluate how much money you will save by incorporating the nutrient source vs. leaving it on the soil surface.

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