• Using Soil Survey Data for Zone-Based and Grid-Based Fields

    When the Sync with a Source option is selected for Soil Type or Slope layers on a Grid-Based field, 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 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, individually by zone, or can be submitted spatially using grid- or zone-sampled shapefiles and integrations.  In all cases, the % organic matter and sample depth are required.


  • Previous Crop

    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). We are working on incorporating cover crops and other crops into the Adapt-N rotation options. In the meantime, 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. 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.
    • Cover Crops: Currently your best option is to use a cover crop credit (if applicable) as suggested by your local extension system. We plan to have a beta-module for cover crops available for testing for the 2016 season.
  • Expected Harvest Population

    Adapt-N asks for an approximate harvest population to create your nitrogen recommendation.  Plant harvest 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:

    1. Crop Establishment and Input (CEI) Applications
    2. Crop Establishment and Input (CEI) Recommendations

    Adapt-N automatically calculates 90% of the planting rate for use as Expected Harvest Population when importing from SST only.  When using the shapefile import and entering a constant value, Adapt-N will not calculate 90% of the planting rate and users must do that manually within the file. 

  • Expected Yield

    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.   

    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.

  • Tillage Methods

    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:

    1. 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.
    2. No-Till: no additional input values are needed.  This is modeled equivalently to Conservation Tillage with 100% residue.
    3. Spring Tillage (only): enter the approximate date of tillage and the approximate depth of tillage.
    4. Fall Tillage (only): no additional input values are needed.
    5. Fall and Spring Tillage: No additional input values are needed.
    6. Strip-Till/Zone-Till (Spring): no additional input values are needed.  Adapt-N assumes a residue percentage of 75%. 
    7. Strip-Till/Zone-Till (Fall): no additional input values are needed.  Adapt-N assumes a residue percentage of 75%. 
    8. Ridge-Till (Spring): No additional input values are needed.  Adapt-N assumes a residue percentage of 50%.
    9. 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.edu/extmedia/AY/AY-269-W.pdf.