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Title: ASSESSING THE SPATIAL DISTRIBUTION OF PLANT LITTER

Author
item Daughtry, Craig
item Hunt Jr, Earle
item Walthall, Charles
item Gish, Timothy
item LIANG, S - UNIVERSITY OF MARYLAND
item Kramer, Edward

Submitted to: Airborne Visible Infrared Imaging Spectrometer Earth Science & Applications
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Quantifying crop residue cover on the soil surface is important for improving estimates of surface energy balance, net primary productivity, nutrient cycling, and carbon sequestration. Quantifying crop residue cover is also an important factor in controlling soil erosion and evaluating the effectiveness of conservation tillage practices. By reducing the movement of eroded soil into streams and rivers, the movement of nutrients and pesticides is reduced. The overall result is less soil erosion and improved water quality. Current methods for quantifying crop residue cover are tedious and somewhat subjective. The standard technique for measuring crop residue cover used by the USDA Natural Resources Conservation Service (NRCS) is visual estimation along a line-transect. Rapid, accurate, and objective methods to quantify residue cover are needed In this preliminary study, pairs of spectral vegetation indices (e.g., Normalized Vegetation Index, NDVI, and Cellulose Absorption Index, CAI) identified green vegetation, crop residues, and bare soil fields. A multiband radiometer with the two NDVI bands and the three CAI bands could be used as a replacement for the line-transect for measuring crop residue cover in fields. Regional surveys and maps of crop residue cover and conservation tillage practices may also be feasible using hyperspectral imaging systems (e.g., Airborne Visible Infrared Imaging Spectrometer, AVIRIS) that have the required radiometric, spatial, and spectral resolution.

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. In this preliminary study, the Normalized Vegetation Index (NDVI) and the Cellulose Absorption Index (CAI) provided better separation of fields with residue than the end-member analysis. A multiband radiometer with the two NDVI bands and the three CAI bands could be used as a replacement for the line-transect for measuring crop residue cover in fields. Regional surveys and maps of crop residue cover and conservation tillage practices may also be feasible using hyperspectral imaging systems (e.g., Airborne Visible Infrared Imaging Spectrometer, AVIRIS) that have the required radiometric, spatial, and spectral resolution.