Utilizing New Multispectral Imaging Sensors for the Assessment of Zea Mays Nitrogen Status.

Improved efficiency of Nitrogen (N) fertilizer applications is an issue of importance for the agricultural community. The environmental and economic considerations of optimizing N input to yield ratios warrant research in topics including optimal timing of fertilization, effectiveness of variable rate applications for improving Nitrogen Use Efficiency (NUE), and abilities of scientific methods to detect the onset and spatial variability of N stress. Remote sensing techniques have been shown to be capable of assessing the N status of crops. A new generation of compact multispectral imaging sensors opens possibilities for rapid acquisition of crop imagery at high spatial resolution utilizing unmanned aircraft systems (UAS). This imagery with spatial resolutions on the order of square centimeters can potentially be filtered to exclude background, glare and shadow pixels which are essentially “noise” masking the signal of the plants chlorophyll status, significantly improving results obtained from lower resolution imagery whose pixels contain a greater mixture of plant, soil, and lighting conditions. The potential for filtering multispectral imagery pixels that contain minimal crop information and to improve the assessment of the spatial variability of corn N status is investigated.