Badger Beat
Using NDVI for Nitrogen Management in Potato Handheld sensors prove useful in predicting yield and stress, and adjusting nitrogen applications By Matt Ruark, UW-Madison Department of Soil Science
Non-destructive sensing of biomass (sometimes called proximal sensing) is a highly desired tool for agricultural management. For example, not only would sensing the nitrogen (N) content of aboveground plant biomass rather than physically sampling it save time, it would also provide information instantaneously rather than having to wait on lab results. (ReflectanceNIR + ReflectanceRed). One particular sensing measurement that has shown value in N management is the normalized difference vegetation index (NDVI). NDVI can be measured through several sensing devices now available as hand-held devices. The sensor measures reflectance at two parts of the electromagnetic
spectrum, near infrared (NIR) and visible red. Chlorophyll absorbs red light, and thus less reflectance means greater greenness (chlorophyll activity). Specific and singular NIR and visible red wavelengths are typically used, and NDVI is calculated as: (ReflectanceNIR – ReflectanceRed) /
The use of active sensors has been shown to be beneficial in adjusting inseason N applications for grain crops, but little work has been done with potato. The use of NDVI (and other sensing measurements) has the potential continued on pg. 50
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