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Use of Spectral Radiance to Estimate In‐Season Biomass and Grain Yield in Nitrogen‐ and Water‐Stressed Corn
Author(s) -
Osborne S. L.,
Schepers J. S.,
Francis D. D.,
Schlemmer M. R.
Publication year - 2002
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2002.1650
Subject(s) - biomass (ecology) , radiance , environmental science , canopy , irrigation , evapotranspiration , remote sensing , growing season , agronomy , sampling (signal processing) , hydrology (agriculture) , biology , botany , ecology , physics , geography , geotechnical engineering , optics , detector , engineering
Current technologies for measuring plant water status are limited, while recently remote sensing techniques for estimating N status have increased with limited research on the interaction between the two stresses. Because plant water status methods are time‐consuming and require numerous observations to characterize a field, managers could benefit from remote sensing techniques to assist in irrigation and N management decisions. A 2‐yr experiment was initiated to determine specific wavelengths and/or combinations of wavelengths indicative of water stress and N deficiencies, and to evaluate these wavelengths for estimating in‐season biomass and corn ( Zea mays L.) grain yield. The experiment was a split‐plot design with three replications. The treatment structure had five N rates (0, 45, 90, 134, and 269 kg N ha −1 ) and three water treatments [dryland, 0.5 evapotranspiration (ET), and full ET]. Canopy spectral radiance measurements (350–2500 nm) were taken at various growth stages (V6–V7, V13–V16, and V14–R1). Specific wavelengths for estimating crop biomass, N concentration, grain yield, and chlorophyll meter readings changed with growth stage and sampling date. Changes in total N and biomass in the presence of a water stress were estimated using near‐infrared (NIR) reflectance and the water absorption bands. Reflectance in the green and NIR regions were used to estimate total N and biomass without water stress. Reflectance at 510, 705, and 1135 nm were found for estimating chlorophyll meter readings regardless of year or sampling date.