Publication Abstracts

Collins 1978

Collins, W., 1978: Remote sensing of crop type and maturity. Photogramm. Eng. Remote Sens., 44, 43-55.

A red-shift in the chlorophyll absorption edge of heading wheat and grain sorghum is clearly visible in high-spectral resolution measurements made from a low-flying aircraft over Imperial Valley, California. The position of the absorption edge shifts progressively toward the longer wavelengths during the crop growth cycle, reaching a maximum in the fully-headed pre-ripening stage. The red-shift of 7 to 10 nm can be measured by using 10 nm-wide spectral bands, centered at 745 nm and 785 nm. These two bands, plus a band in the pigment absorption region at 670 nm, contain enough information to identify wheat and grain sorghum in the heading stage, to indicate the degree of heading, and to indicate canopy density during the heading stage.

A smaller red-shift in the absorption edge is also visible in nongrain crops during maturation. The working hypothesis formed as a result of this study is that the red-shift results from increasing chlorophyll a concentration during the growth cycle. The greater concentration produces molecular aggregation by chlorophyll-chlorophyll and possibly chlorophyll-protein interactions. Polymer forms shift the far-red absorption edge by adding closely spaced absorption bands to the far-red shoulder of the main chlorophyll a band.

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BibTeX Citation

@article{co04400m,
  author={Collins, W.},
  title={Remote sensing of crop type and maturity},
  year={1978},
  journal={Photogramm. Eng. Remote Sens.},
  volume={44},
  pages={43--55},
}

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RIS Citation

TY  - JOUR
ID  - co04400m
AU  - Collins, W.
PY  - 1978
TI  - Remote sensing of crop type and maturity
JA  - Photogramm. Eng. Remote Sens.
VL  - 44
SP  - 43
EP  - 55
ER  -

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