Crop-reflection-based DSS for supplemental nitrogen dressings in potato production

To achieve a certain yield level a potato crop needs to amass sufficient nitrogen in its foliage well before crop maturity. This paper shows a decision support system for supplemental nitrogen dressing using the following quantitative relationships: the relationship between final tuber yield and minimum total foliage nitrogen content and the timeslot when this amount should be present. Crop reflection characteristics were related to this amount of nitrogen assuring that all elements of the decision support system are in place. A grower will need to know what yield he or she is aiming for and about half the required amount of nitrogen is then supplied before or at planting. Before mid-season the crop is assessed with crop reflection at two wavelengths to verify the amount of nitrogen in the standing biomass. If the difference between the amount present and required is applied.