Field canopy and leaf level fluorescence for distinguishing plant condition differences due to nitrogen fertilization level

Actively induced fluorescence techniques were investigated for their potential to detect differences in plant condition due to levels of nitrogen fertilization rate in field grown corn (Zea mays L.). Eight levels of N fertilization were applied representing treatments from over fertilization to under fertilization. Laboratory leaf fluorescence measurements were compared to laser induced fluorescence (LIF) canopy level "footprint" measurements. Fluorescence emission data were collected in the 360-800 nm region of the spectrum. Where there were no significant differences in chlorophyll concentration or corn grain yields, T test of fluorescence maxima from these regions indicated that plant growth condition due optimum levels of N fertilization could be separated from less efficient levels. Similar trends were observed with the leaf level and canopy level measures.