This type of recommendation looks at logged data and uses removal coefficients to calculate the amount of product that should be applied.
The standard calculation is (Average Yield * Removal Coefficient)/Product % = Average Application Rate
💡TELUS Agronomy uses the following website for default Removal Coefficients. http://www.ipni.net/article/IPNI-3296 Currently, Corn Grain, Soybean Grain, Wheat Grain, Barley, Canola, Oat, Sorghum, and Sunflower are part of the default coefficients.
Here is an example: A yield removal rec for P205 DAP (18-46-0) on 200bu average corn. The standard of the system Removal Coefficient for Corn, Grain is .35 lbs P2O5/bu, so your equation would like this:
(200 * 0.35) / .46 = 152 lbs average application
* These removal coefficients are recommended by the International Plant Nutrition Institute (IPNI).
* Most nutrient recommendations refer to pounds of P2O5, not pounds of actual P. The same is true for potassium - recommendations refer to pounds of K2O, not pounds of actual K. Nitrogen recommendations refer to actual pounds of N.
To calculate the percentage of actual (elemental) P in an amount of P2O5, multiply the amount of P2O5 by .44.
To calculate what percentage of oxide P (P2O5) equates to an amount of actual P, multiply the amount of actual P by 2.29.
To calculate the percentage of actual (elemental) K in an amount of K2O, multiply the amount of K2O by .83.
To calculate what percentage of oxide K (K2O) equates to an amount of actual K, multiply the amount of actual K by 1.2.
* However, most soil tests refer to the elemental form of the nutrient in either pounds (lbs) or parts per million (ppm).
To convert ppm to lbs, multiply ppm by 2.
To convert lbs to ppm, divide by 2.
Common Question: When running an MYYA is the mean relative yield the same thing that is used when running a multi-year yield removal rec?
No. When running MYYA, mean relative yield classifies yield data as a percent of mean yield for the entire field. The result of each year is averaged to provide the client with a map of the relative yield over time. For a multi-year removal rec, each year is run on its own, and removal is calculated. Then the years are added together for your final application rate.
Create a Yield Removal Recommendation
Navigate to VR Fertility Recommendations.
Select 'New' in the bottom right.
Select 'Yield Removal' for type.
4. Select the field(s), then select 'Next'.
5. Select the Elements and Products and enter prices (if desired).
6. Select if a Flat Rate of yield data will be used or if Logged Data will be used. If logged data is used, be sure to select the year(s) you would like to include.
Make sure to click on the box with the element name or the checkmark next to it to create a rec for each.
There will not be a rec run for an element if the name of it is not highlighted in blue.
7. If using flat rate removal, choose a crop and enter a yield value.
8. On the next screen, enter in any changes to min, max, and rounding rates and select 'Run Rx' or 'Run as Batch'.
Here you can also edit the removal coefficient for each element, which will default to what is set in the organization settings.
9. By default, the application recommendation does not include removal rates when the fertility rate recommends "0".
10. This can be changed by going into your location settings and clicking on 'Fertility Analysis'. There are toggle switches for:
Apply Removal Rates to Zero Recommendation Areas OR have areas where you do not take into account those rates.
11. There is also an option to have the system auto-fill in the average yield value where there is missing yield data.
Apply Average Yield value to Missing Yield Areas OR to have areas that will call for "0" recommendations.
What is the difference between 'Run Rx' and 'Run as Batch'?
Run Rx generates one combined shapefile for all field boundaries and has separate shapefiles for each product. Below is an example of how the files will look.
Run as Batch allows you to have individual field shapefiles for each product. Below is an example of how the download will look.
12. The review page will show a preview of the Yield Removal Rx. Available options are as follows;
A. Prescription Name - Enter the name of the prescription. This is how it will display in the list view. This will not be the name used for the shapefile export.
B. Season Filter - This allows you to choose what season your recommendation is for.
C. Product Tile - Displays important information like Product Name, Average Application Rate, Total Product, and Min and Max Application Rate.
D. Map/Details - The map displays a preview of the map. Details display a table showing the Sample ID, Nutrient Result Value, and Product Rate.
E. Layer Picker - This allows you to choose different map provider backgrounds.
F. Quick Report - Download a quick printable report, see Fertility Recommendation Report. This is a default report and is not customizable.
G. Report - Customize-able fertility report that allows several options to be included, excluded, or edited. See Fertility Recommendation Report for more information.
H. Download Shapefile - Download a shapefile of the variable rate recommendation.
I. Export Prescription - Customize the fertility export. Items to choose from include:
Edit the product name in the export file
Select how to round the value of the recommendation
Select the number of files (File per product, or combine all products into one file)
Select polygon type (single polygon shape or multi polygon shape)
J. Info - Displays the information used to create the recommendation such as equation, min, max, rounding rates, yield goal etc.
K. New Template - This allows you to save the values you used for this recommendation as a template to be used again.
L. Save - Save the recommendation for later printing or exporting.
