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Title: REMOTE-SENSING MEASURES OF COTTON MATURITY - CUTOUT AND BOLL OPENING

Author
item HARRIS, F - DREC
item ENGLISH, PATRICK - DREC
item SUDBRINK, DONALD - DREC
item NICHOLS, STEVE - DREC
item SNIPES, CHARLES - DREC
item WILLS, GENE - DREC
item Hanks, James

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/5/2004
Publication Date: 6/5/2004
Citation: Harris, F.A., English, P.J., Sudbrink, D.L., Nichols, S.P., Snipes, C.E., Wills, G., Hanks, J.E. 2004. Remote-sensing measures of cotton maturity - cutout and boll opening. National Cotton Council Beltwide Cotton Conference. 2004. CD-ROM, pp. 1869-1875.

Interpretive Summary: Studies were conducted to determine if radiometry data and/or multi-spectral imagery data could be used to estimate cotton maturity parameters. Several indices that use radiometry data or information extracted from images to represent plant growth status are the Normalized Difference Vegetation Index (NDVI), Visible Atmospherically Resistant Index (VARI), and Green Vegetation Index (GVI). NDVI (Normalized Difference Vegetation Index) was used to classify portions of the field to spray (NAWF = 5 + <350 HU) or no spray (NAWF = 5 + >350 HU) where NAWF = Node Above first position White Flower and HU = Heat Units. Replicated experiments with planting date and cotton variety treatments were conducted in 2002 and 2003 to determine if radiometry data and/or multi-spectral imagery data could be used to estimate time of cutout (NAWF = 5) in a cotton crop. A GER 1500® spectroradiometer was used to collect radiometry data. Reflectance data were used to calculate percent reflectance from which various indices were calculated and analyzed for correlation to NAWF and percent open bolls. The widely used NDVI was not closely correlated to NAWF or percent open bolls. Two other indices, VARI (Visible Atmospherically Resistant Index) and GVI (Green Vegetation Index), were closely correlated to the maturity parameters, especially for the 2002 data.

Technical Abstract: Imagery data were used in 2001 to classify a cotton field into two zones based on COTMAN spray termination rules. NDVI (Normalized Difference Vegetation Index) was used to classify portions of the field to spray (NAWF = 5 + <350 HU) or no spray (NAWF = 5 + >350 HU) where NAWF = Node Above first position White Flower and HU = Heat Units. Replicated experiments with planting date and cotton variety treatments were conducted in 2002 and 2003 to determine if radiometry data and/or multi-spectral imagery data could be used to estimate time of cutout (NAWF = 5) in a cotton crop. This report focuses on radiometry data acquired with a GER 1500® spectroradiometer. Reflectance data were used to calculate percent reflectance from which various indices were calculated and analyzed for correlation to NAWF and percent open bolls. The widely used NDVI was not closely correlated to NAWF or percent open bolls. Two other indices, VARI (Visible Atmospherically Resistant Index) and GVI (Green Vegetation Index), were closely correlated to the maturity parameters, especially for the 2002 data.