Why is a field's productivity class on the productivity report different from what I see in the Standards and Criteria?
Problem Description: The productivity report shows a soil series and a productivity class for several common crops for each field in the plan. But the user tries to verify a productivity by looking it up in Table I-1 of the Nutrient Management Standards and Criteria and finds it doesn't agree with what's in the report.
Answer: We've had a few false alarms over the years where people think they've found an error on the productivity report. So far, it has always been explainable. You don't necessarily see all the relevant information on the productivity report itself to duplicate its results. If you think you're seeing a discrepancy like this there are two things to check:
Are there multiple soil series in the field? The productivity report only shows the dominant soil series. But there may be other soil series present. The place to check is the soils tab of the Farm Edit screen. NutMan will calculate the yield as a weighted average based on all the soil series present in the field, not just the dominant soil series.
Is there a yield adjustment for slope in this field? NutMan adjusts yield downwards for high slope according to information in Table I-4 in the Standards and Criteria. This can change a field's productivity class for a crop shown on the report.
If you still see a discrepency after accounting for these possible effects, send the plan file as an e-mail attachment to user support (jimvenuto@isislabs.com) with a description of the problem.
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