Early Detection of Nitrogen Deficiency in Corn Using Fluorescence.

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Soil scientists have made significant progress in quantifying and characterizing spatial variability in soils using proximal sensing technologies. However, such soil sensing efforts must be coupled with crop sensing to make better and most efficient nutrient management decisions. Proximal sensing offers the possibility to better target nitrogen fertilizers. Current sensing technologies based on reflectance do not provide reliable information in early growth stages of corn, which is the optimal period for nitrogen deficiency correction to prevent yield loss. A new type of sensor using induced fluorescence offers the possibility to detect nitrogen deficiency in corn. This study attempts to determine if fluorosensing allow detection of nitrogen deficiency at early growth stages of corn. Our data shown that fluorescence sensor can detect nitrogen deficiency from growth stage V6 for most fluorescence based parameters. With blue light induction, the nitrogen deficiency can even detect nitrogen deficiency as early as V5 growth stage of corn. At close proximity soil covered with residues can contribute soil background noise in the fluorescence signal, however, above 15 cm this noise is not significant.