Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 22, 2001
Publication Date: N/A
Technical Abstract: Quantifying crop residue cover is important for evaluating the effectiveness of conservation tillage practices and for estimating surface energy balance, nutrient cycling, and carbon storage. Traditional methods of quantifying crop residue cover are labor intensive and are generally inadequate for rapid assessment of crop residue cover in many fields. Reflectance spectra of crop residues and soils were acquired over the 400-2500 nm wavelength region at 1 nm intervals. Although the spectra were very similar in the 400-1100 nm region, three broad absorption features in the 1500-2300 nm region were evident in the residue spectra but not in the soil spectra. Band-depth analysis of these features indicated that quantitative assessment of crop residue cover is possible. Airborne Visible Infrared Imaging Spectrometer (AVIRIS) radiance data were acquired over fields, pastures, and woodlands near Beltsville, MD in May 2000. Pairs of vegetation indices that included a visible and a near infrared band plus the absorption feature at 2100 nm provided better identification of diverse cover types than the end-member analysis. Regional maps of crop residue cover and conservation tillage practices may be feasible using hyperspectral imaging systems that have the required radiometric, spatial, and spectral resolution.