Adapt-N's full-field variable rate prescription feature provides powerful nitrogen recommendations that are weather-adjusted, site-specific, and account for substantial sub-field variation. Just like with any other Adapt-N recommendation, users can control various inputs and can analyze the makeup of the recommendation before deciding exactly what to apply in the field. Service Provider, Enterprise, and Precision Trust licenses may request access to the Variable Rate features by contacting firstname.lastname@example.org.
Creating a Field for Variable Rate Purposes
Variable rate prescriptions may be generated by importing a Shapefile or by syncing the field boundaries to a data source, such as the agX Platform (see instructions here). Fields drawn by hand within Adapt-N are not eligible for variable rate prescriptions due to the precision needed to appropriately utilize the recommendation. Shapefile imports should be conducted for a single field, although multiple polygons within that field are supported. Full instructions on importing field boundaries using Shapefiles are located here.
Once a field boundary has been imported into Adapt-N, select the "VRT Grid" zone creation method:
When looking at the Fields & Zones view, VRT Fields have a graph icon next to their name, whereas point-based fields have an arrow next to their name (to expose manually created zones):
Configuring a Variable Rate Field
Click "Configure Field" on the Fields & Zones view, or click the "Configure Field" item in the Field menu, to enter the VRT field configuration interface:
The Variable Rate Field Configuration Interface is then displayed. Similar to point-based fields, users provide information specific to the field and farm management practice. The configuration for each layer of data is accessed by clicking on the layer name. The following layers may be configured in variable rate fashion by importing a Shapefile or by Syncing to a Data Source:
- Soil Type
- Soil Organic Matter
- Expected Harvest Population
- Expected Yield
- Nitrogen Applications
Other layers of data, including crop rotation, tillage method, and manure and irrigation applications, are configured in a flat-rate fashion for the entire field. These layers may become variable in the future. If you are syncing a field to the agX Platform, please reference this article instead, as the remainder of this article assumes the field was imported using a Shapefile.
Click a layer's name to expose its data import options. For example, the Soil Organic Matter layer accepts a Shapefile or a Constant Value. Click the data import type (e.g. Shapefile) to expose additional controls, including a way to locate the Shapefile on your computer, input fields for additional required data, and in some cases optional input fields for Default values.
- Shapefiles must be submitted in the form of a Zipfile, containing the individual Shapefile components (.shp, .shx, .dbf, .prj).
- For soil type, slope, expected harvest population, and nitrogen applications, the data within the Shapefile should be polygon-based. For soil organic matter, either polygon or point-based data is accepted.
- You may submit multiple columns within a single Shapefile, which you would select within each layer, or you may submit separate Shapefiles each with one column of data. If multiple columns of data exist, you will be prompted to identify the proper column of data for the layer being configured.
Here is a view of an example Shapefile, containing columns as follows:
- AREASYMBOL: represents the FIPS code required by the Soil Type Import (FIPS is a 2-digit state and 3-digit county code).
- MUSYM: represents the MapUnit Symbol required by the Soil Type Import. This corresponds to the SSURGO soil database provided by NRCS.
- Yield: the expected yield value for each polygon within the field, represented in bu/ac.
- SOM: represents the soil organic matter % for each polygon within the field.
- Population: represents the expected harvest population for each polygon within the field.
- PreplantN: represents pounds per acre of nitrogen already applied to the field.
This sample Shapefile is available for download at the bottom of this page.
When submitting the Shapefile to Adapt-N, a dialog box will prompt you to select the appropriate column in your shapefile for the data layer you are submitting:
Any column name is acceptable, as long as it does not start with a number. When the Shapefile has been processed, a confirmation will indicate the area of the field covered; in cases when the Shapefile does not cover the entire field, the optional Default Value will be used.
All layers are required except for Nitrogen Applications, Manure Applications, and Irrigation Applications. You can partially complete a field configuration and return to it later, as each layer is saved individually once submitted.
Running a Variable Rate Recommendation
Once the required layers have been configured, Activate the field (either from the top of the VRT configuration interface or from the Fields & Zones view). To initiate the variable rate recommendation, click Run Active Zones from the Field menu. This launches a background process to run the necessary simulations for that field.
You may continue working elsewhere within Adapt-N, or you may visit the Field Recommendation page to monitor its progress. A notification badge will be displayed in the navigation bar, above your name, when the recommendation is complete (it may take several minutes). Alternatively, you may click on the icon above your name to check on the status of processing and completed recommendations. Click on the field name to access the recommendation:
Or, visit Fields & Zones and click "Field Rec" on the Field menu to access the recommendation page:
When loading a recommendation that is still processing, partial results will be displayed, with the option to reload the page.
Viewing a Variable Rate Field Recommendation
Once configured and activated, the Adapt-N Variable Rate Recommendation runs automatically on a daily basis, taking advantage of updated weather and any changes entered by the user. Additional features of the recommendation include:
- Summary of Field Rec: includes the minimum, average, maximum, and total pounds of N recommended
- Date selector: select from any date back through 2010, in order to re-run the prescription using the actual weather from the start of the selected season to the date specified (all management dates are automatically adjusted for the simulation)
- Interactive map: click on any of the grid cells to see the specific recommendation for that 60' x 60' cell; click view details for full scientific simulation results, including PDF reports and interactive graphs for that cell
- Interactive graph: hover your mouse over bars in histogram or the values in the legend to highlight the grid cells on the map applicable to those recommendation ranges
- Summary of VRT inputs: shows the minimum, average, and maximum values for the variable rate inputs; if applicable, a summary of nitrogen, manure, and irrigation applications is also displayed
- Export Recommendation: choose export format, products, and make rate modifications. View this article for details.