The Rooting Depth parameter for a zone is used to determine whether nitrogen that has moved within the soil profile during the season is still within reach of the crop's roots, or whether it is effectively lost. Adapt-N has developed a database of realistic rooting depth defaults for each combination of soil texture and drainage classification in each county. However, since management practices and field/weather conditions can have a significant impact on rooting depths over time, we recommend users evaluate actual rooting depth in their fields and make adjustments accordingly. Consider taking penetrometer measurements to account for compaction and rootzone limitations. Consider weather influences that may impact rooting depth (e.g., very high rainfall tends to reduce rooting depth).
Evaluating Rooting Depth in a Field
The easiest time to evaluate rooting depth of a fully grown crop is after the season ends. In a few representative locations, dig deep enough so you can easily pull out the root mass without breaking off a lot of roots, or dig a small trench and view them from the side. The rooting depth should be assessed based on the vertical proliferation of a majority of roots, not an incidental root that may have gone deeper than most. We do not recommend relying on rooting depth values from soil survey databases, which tend to be overestimated. The actual rooting depth discovered should then be applied to Adapt-N for the following seasons. In the case of a very wet early growing season, it may be worthwhile to assess whether rooting depths are reduced, especially in fine-textured soils and when drainage is imperfect, and update Adapt-N accordingly.
If you have not had an opportunity to evaluate rooting depth in advance of the season, it can still be evaluated during the season. We recommend digging up roots no earlier than V7.
Modifying Rooting Depth Values in Adapt-N
Fields can have their Rooting Depth values modified either as a flat value, or spatially, via the Configure Field interface. If a Shapefile is provided, values should be specified in inches. Else, the "Enter a Constant Value" option enables the entire field to be made more shallow, deeper, or set to a specific value.
When the Rooting Depth panel is open, the legend in the map interface displays the current values across the field.