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Manure Calculator for Corn

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This calculator will help determine the value of solid beef feedlot manure for corn production in North Dakota.

an app icon with a green background and icons representing a yellow calculator and a white plant

Paulo Flores, Precision Agriculture Specialist at the NDSU Carrington Research Extension Center, developed an Excel spreadsheet (NDSU Manure Application Calculator for Corn; hereafter “Calculator”) that allows farmers to compare the nutrient value, on a cash basis, of solid beef feedlot manure as a source of nitrogen (N) and phosphorus (P) to commercial fertilizers for corn production in North Dakota. Calculations are based on the assumption that the cost per unit of nutrients for manure and commercial fertilizers are the same, and they vary according to the price of different fertilizer sources that producers can choose from in the spreadsheet. 

In this second version, sulfur (S-SO4) calculations were added in addition to those regarding N, P and potassium (K, as K2O) present in the first version. Moreover, the manure cash value on this version is calculated with and without considering the extra K2O provided by manure application for those producers that would not apply K2O on their operations.

Information regarding field (area, soil nutrient content), crop (yield potential, nutrient recommendations), commercial fertilizers (price, nutrient content, application cost and rate), manure (nutrient content, availability factors, additional nutrient value, application cost and rate) and interactions amongst some of those variables are taken into consideration in the calculations.

The values in the light blue cells are customizable and different options can be selected from the drop-down menus (top right corner), allowing producers to change those values to reflect the numbers of his/her operation. Once the light blue cells are filled out, the Calculator will provide a “Net Cash Value” per acre when using manure instead of commercial fertilizers as a source of N or P for corn. Producers can make changes to the values in the light blue cells and/or pick a different option in the drop-down menus at any time. That can be very useful for producers because it allows them to identify several factors that can affect the economics of manure application, such as the maximum hauling distance and the most adequate truck hauler/spreader capacity. Using the drop down options, producers can use the Calculator to select the most economical combination of fertilizer sources to reach the corn N or P requirements.

The Calculator calculates a balance of nutrients when using manure and/or commercial fertilizer alone on in combination with each other. A negative “nutrient balance” means that additional nutrients are needed to reach the recommended amount of each specific nutrient (N, P, K, S). Calculator will provide the rates and the costs associated with the amount of commercial fertilizer that should be supplied to bring the nutrient balance to zero. There is a “nutrient balance” line when using only manure or fertilizers as source of nutrients for corn production, which are independent of each other. The commercial fertilizer rate line on the “manure section” is the fertilizer rate needed to reach the nutrient recommendations for corn in addition to the manure application. The fertilizer rate on “fertilizer section” is the rate to reach the nutrients recommendations for corn using commercial fertilizers alone.

Once the values are set, producers can print a copy of the N and/or P report (information inside of the green box only), by clicking on the “Print Report” button built into each spreadsheet, or save the file on his/her computer.

About the Calculator

- Please "Enable Active Content" on Microsoft Excel so the calculator can perform as expected.

-  On the home screen, producers can choose to apply manure based on "Nitrogen Corn Requirement" or "Phosphorus Corn Requirement".

- The Calculator is not intended to provide N recommendations for corn. Please visit the "North Dakota Corn Nitrogen Calculator" website to find out the N recommendation for your operation.

- The Calculator has an option to run using average values for manure nutrient content, but because the amount of nutrients in manure vary greatly, it is strongly recommended that producers have the manure analyzed before they apply it to their fields.

More information (Instructions/Information) about the Calculator can be found on the tab entitled “Instr-Info” in the Excel workbook that contains the Calculator. A printer friendly version of the “Instructions/Information” and the Calculator can be downloaded by clicking on the links provided on top of this page.

For comments, questions and/or suggestions please contact Paulo at the CREC by phone (701.652.2951) or email (paulo.flores@ndsu.edu).