|Pinter Jr, Paul|
|Leavitt, S - UNIV OF ARIZONA|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 28, 1997
Publication Date: N/A
Technical Abstract: Spring wheat (Triticum aestivum L., cv Yecora Rojo) was grown in a production environment using Free-Air-Carbon Dioxide Enrichment (FACE) at Maricopa, AZ, during the 1995-96 and 1996-97 seasons. Main treatment plots provided exposure to ambient and elevated (ca. 200 umol/mol above ambient) CO2. The main plots were split, with one half receiving low (ca. 70 kg/ha) and the other high (ca. 350 kg/ha) amounts of nitrogen fertilizer. Nitrogen applications occurred at tillering, stem elongation, anthesis, and early grain fill. A high resolution spectroradiometer was used to measure reflectance factors of the canopy from 350 nm to 1050 nm at 1 to 2 week intervals throughout the season. Hemispheric reflectance and transmittance properties of individual plant leaves, stems, and heads were also measured using the same radiometer and an external integrating sphere. Hyperspectral properties varied with experimental treatment, organ and normal end-of-season tissue senescence. Significant differences were found in spectra from plants exposed to different N treatments; changes caused by different CO2 levels were more subtle.