June 7, 2011
We have gotten some feedback on prioritizing Adapt-N inputs according to their importance. It was suggested that we indicate the inputs where accurate information is critical, and inputs where less accuracy is needed. This spreadsheet [.xlsx file] provides more detailed information of the input requirements. In general, all requested information is relevant and will contribute to the accuracy of the tool, but you may consider the following:
- Expected harvest populations: Approximate values are sufficient
- Date of planting: Accuracy within a couple of days is sufficient as planting campaigns generally span a rain-free period
- Rooting depth: Approximate values are sufficient. If data are difficult to obtain or estimate, default values can be used
- Slope: Approximate values are sufficient
- For spring plowing, approximate dates are sufficient
- Conservation tillage: approximate residue levels are sufficient. The attached spreadsheet provides guidance.
Note also that the following entries are important to be accurate:
- Measured organic matter contents help improve model predictions significantly. The default % SOM values generally over-estimate the actual % SOM that has been reported for fields under cultivation. Therefore, we strongly recommend an estimate of the % SOM from a soil test for the location/management zone of interest to maximize the benefits of this tool.
- The N recommendations are very sensitive to expected yield inputs. Entered yield values should be realistic, not based on an overly ambitious aim. As a general rule, the harvests from the last three years should provide guidance.
We will be adding a discussion of the relevance of the inputs to Adapt-N output as part upcoming Adapt-N workshops and training sessions. We will also make this information available electronically from the Adapt-N website in the near future.