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United States Department of Agriculture

Agricultural Research Service

Title: Comparison of Methods for Remote Sensing of Plant Growth and Nutrient Management

item Hunt, Earle
item Daughtry, Craig
item Walthall, Charles
item McMurtrey Iii, James
item Dulaney, Wayne

Submitted to: Crop Science Society Of America
Publication Type: Abstract Only
Publication Acceptance Date: October 12, 2001
Publication Date: October 22, 2001

Technical Abstract: Remotely sensed imagery can be used to determine plant growth and nutrient status, and thus is an important geospatial data layer for site-specific agriculture. Side-dress nitrogen for maize is generally applied in June/early July, when clouds frequently inhibit image acquisition. Unmanned aircraft are being developed and may be an important image data source with hhigh spatial resolution. We tested a radio-controlled model airplane equipped with a camera and Kodak EIR color-infrared (CIR) film. The plane was flown between 125 and 175 m above ground level; the effective resolution of the camera and film was about 6 cm. The slides were scanned into digital image formats and georectified using ground control points. These data were compared to digital multispectral data, which were converted to reflectances using an uplooking pyranometer; the pixel sizes were about 0.5 m. The normalized difference vegetation index (NDVI) was calculated from both sensors, and were highly correlated to maize biomass. Thus, radio-controlled model aircraft (airplanes or helicopters) may be an effective source of remotely sensed data which would be less costly and more timely than other sources.

Last Modified: 4/21/2015