Spring 2020 Model Update
Adapt-N uses a mass-balance equation to derive a final N recommendation, which includes the final crop N needs to achieve the expected yield, soil N availability, current crop N status, future N credits, and potential loss and risk factors. In this approach there is a linear relationship between the expected yield and the amount of recommended nitrogen: higher yields require equivalently more N. Recent research has demonstrated that this relationship is not linear with fields that have low yield potential. The underlying causes - compaction, drainage, water deficits, etc. - also affect the crop’s ability to take up the available nitrogen, which results in lower nitrogen use efficiency. Based on results from many field trials, Adapt-N has implemented an improved methodology to account for decreased N use efficiency in cases where yields are below-normal for a region. Adapt-N already recommends lower nitrogen for fields with lower expected yields; it now also accounts for the reduced nitrogen use efficiency in those low yielding fields, having an effect of slightly increasing recommendations in such cases.