University of Maryland Extension

N Credits for Biosolids

Q. I am writing a nutrient management plan for a farm that received biosolids last year. I know that I need to enter this information into the NuMan Pro history so that the appropriate nitrogen (N) credits are assigned. The biosolids applicator provided a list of all of the materials applied to each field. Which organic N value should I enter if biosolids from multiple treatment plants were used on the same field?

A. There are a few things to remember when entering biosolids information into the NuMan Pro history.

1) The application rate must be entered in the dry weight basis.

2) You must use the organic N information from the Maryland Department of Environment PAN Rates Table rather than the PAN rate provided by the biosolids applicator.

3) If only two biosolids products were applied to the field and one was obviously applied at a heavier rate, enter the product applied at a heavier rate into the history.

If multiple biosolids products were applied, use the following process to determine which biosolids product to enter into the history:

    1. Enter each of the biosolids into the organics list in NuMan using the organic N from the MDE PAN Rates Table.
    2. Apply each biosolid on the field at the N-based rate.
    3. The biosolid that can be applied at the highest application rate is the one you would enter into the history. (This will be the product that provides the least amount of N credit on the field. This product is selected to minimize the potential for applying inadequate N in any part of the field for the growing crop.)
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