|Corp, L. - NASA GSFC|
|McMurtrey Iii, James|
|Mulchi, C. - UNIVERSITY OF MD|
|Chappelle, E. - NASA GSFC|
|Middleton, E. - NASA GSFC|
Submitted to: Remote Sensing of Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 13, 2003
Publication Date: N/A
Interpretive Summary: Techniques were defined for developing fluorescence imaging systems for monitoring nitrogen level needs in field corn. The systems must be designed in such a way as to collect meaningful fluorescence emission signals from vegetation even in the presence of full ambient sunlight. Current research has focused on utilizing fluorescence imaging systems from ma variety of platforms to receive fluorescence information which can be related to the physiological status of the plant life. The results from these investigations can be used to aid in the design of more advanced mobile field-based Laser Induced Fluorescence (LIF) systems to monitor crop productivity and nitrogen nutrient status.
Technical Abstract: Fluorescence properties of leaves from field grown corn (Zea mays L.) as they relate to varying levels of nitrogen (N) fertilization were defined. A remote non-destructive sensing technique to aid in the determination of optimal rates of N fertilization for corn crops was developed. The field site was divided into four randomized complete blocks each containing eight tN application rates (244, 203, 162, 122, 81, 41, 20, 0 kg N / ha). Fluorescence and physiological measurements were obtained from the uppermost fully expanded leaves at the vegetative (V12), tasseling (VT), and grain fill (R3) growth stages. Fluorescence bands in the blue (450 nm), green (525 nm), red (680 nm), and far-red (740 nm) and ratios of these bands were compared with the following plant parameters: N:C ratio, pigment concentrations, and grain yields. Both the fluorescence and physiological measures exhibited similar curvilinear responses to N fertilization level while significant linear correlations were obtained among fluorescence bands and band ratios to certain physiological measures of plant productivity. The red / blue, red / green, far-red / blue, far- red /green fluorescence ratios are well suited for remote observation and provided high correlations to grain yield, LAI, N:C, and chlorophyll contents. The results from these investigations can be used to aid in the design of more advanced mobile field-based Laser Induced Fluorescence (LIF) systems to monitor crop productivity.