Required Configuration Inputs
Soil Survey Data
When the Sync with a Source option is selected for Soil Type or Slope layers, Adapt-N's internal Soil Survey database is used to configure the field. Specifically, each grid cell in the field will be automatically set with the appropriate values:
- Soil Texture will be specified based on Adapt-N soil regions and databases
- Drainage classification will be set
- Adapt-N's default rooting depth will be set
- The slope % will be set
In cases when the Soil Survey database lacks sufficient information for a part of a field, only then will the user-provided Default Values be used.
In all cases, the system will inform the user the percent of the field which was set automatically vs. by user-provided defaults.
Users always have the option to upload a Shapefile to set these values, instead of using Adapt-N's databases. Soil data will need to include the following columns:
- 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.
Soil Organic Matter
Soil Organic Matter
Adapt-N recommends using a soil organic matter test that was conducted in the last 3 years. Values can be entered as a flat rate for the whole field or can be submitted spatially using grid- or zone-sampled shapefiles or imported through integrations. In all cases, the % organic matter and sample depth are required.
The purpose of providing a previous crop is to provide the model with information about remaining crop residues and their influence on N availability (immobilization in high carbon residue, or additional N in legume residue). If the crop planted in the previous year is not listed as an option under Previous Crop, a crop with a similar growth pattern (planting density, crop residue) should be selected. Please contact email@example.com if you have any questions. Here are a few suggestions about how to generate the most accurate results:
- Small grains, straw harvested: Substitute silage corn for small grains. The reason for this is that, like silage, small grains after straw harvest leave a minimal amount of surface residue, so that little immobilization of nitrogen occurs. The amount of root residue left by densely planted grains is likely similar to more broadly spaced, but larger, corn root residue.
- Small grains, straw left on surface: When following small grains where straw was not harvested (if residue is still fairly thick by corn planting time) use “grain corn” as the previous crop, so that some immobilization of N in residue will be accounted for, although imperfectly.
- Vegetable crops/potatoes: Substitute soybean for vegetable crops/potatoes, but be sure to add the soybean N credit listed on your results page to your Adapt-N recommendation (15 lbs or 25 lbs, depending on location and soil type) for non-legume vegetable crops. Like soybeans, most vegetable crops leave minimal residue, but most do not fix nitrogen.
For Alfalfa, Grass Hay, Mixed Legume Hay, and Sod - a termination date, Legume Percentage, and Termination Method are also required for input. For any other prior crop, it should also be specified whether a forage-sod was planted in the last three years by clicking the checkbox below the dropdown. This will allow the model to account for N dynamics associated with that forage-sod.
Adapt-N asks for an approximate planting population to create your nitrogen recommendation. Plant population options are in increments of 1,000 ranging from 15,000 - 40,000 plants/acre.
When Sync with a Source is selected, Adapt-N will display all available datasets containing planting rate information, including some basic statistics about those planting records. The default value is optional, and will only be used in cases when the selected agX data does not cover the entire field. This includes:
- Crop Establishment and Input (CEI) Applications
- Crop Establishment and Input (CEI) Recommendations
Adapt-N is used as a predictive tool in the early growing season, and the expected yield should therefore be based on an achievable yield, not an average yield, based on the real-world field-specific situation. If seasonal growing conditions are good, we recommend to use the highest yield of the past five years. When the growing season around sidedress time already shows suboptimal conditions (late planting, water stress, pest damage, etc.) adjust the yields downward as appropriate.
Additionally, a planting date and maturity class will also be required with expected yield. Maturities are available for Grain Corn, Silage Corn, Sweet Corn, and Popcorn.
A post-season evaluation of Adapt-N should not be based on the achieved final yield of that growing season, as this may have been impacted by late-season processes like drought, weed competition, hail, or pest pressure that are unrelated to crop N uptake and cannot be predicted at sidedress time. This would not be representative of the use of Adapt-N in a real-world scenario, where an N rate recommendation must be made in spring or early summer.
Adapt-N models the impact of different tillage methods on nitrogen availability. It simulates decomposition of incorporated vs. surface residues, and adjusts temperature and moisture conditions.
There are nine Tillage methods available for use in Adapt-N:
- Conservation tillage: select the approximate % of the previous crop’s residue remaining on the surface after all tillage passes. Conservation tillage leaves at least 25% of the previous crop’s residue on the surface.
- No-Till: no additional input values are needed. This is modeled equivalently to Conservation Tillage with 100% residue.
- Spring Tillage (only): Enter the approximate date of tillage and the approximate depth of tillage.
- Fall Tillage (only): No additional input values are needed.
- Fall and Spring Tillage: No additional input values are needed.
- Strip-Till/Zone-Till (Spring): No additional input values are needed. Adapt-N assumes a residue percentage of 75%.
- Strip-Till/Zone-Till (Fall): No additional input values are needed. Adapt-N assumes a residue percentage of 75%.
- Ridge-Till (Spring): No additional input values are needed. Adapt-N assumes a residue percentage of 50%.
- Vertical Tillage: No additional input vales are needed. Adapt-N assumes a residue percentage of 50%.
Important note: If multiple methods of tillage are used, select the option that most closely reflects the effects on crop residue incorporation.
When specifying Tillage % Residue, only a general estimate of the % residue remaining from the previous year’s crop is needed (the options in Adapt-N are 25, 50, 75, or 100%). For guidance on estimating this value, you can use the percent surface residue values detailed in the following Purdue University fact sheet: https://www.extension.purdue.