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Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Transactions of the ASAE. Vol. 45(3): 865–871 . (doi: 10.13031/2013.8839) @2002
Authors:   E. Fitz–Rodríguez, C. Y. Choi
Keywords:   Bermudagrass, Spectral reflectance, Remote sensing, Multiple spectral data, Vegetation index, Visual grading

Highquality turf demands high water and nutrient inputs, as well as intensive maintenance. Due to decreasing water availability and high maintenance costs, efficient methods of water and fertilizer delivery and identification of sitespecific management areas are required. In the turf industry and turf research, visual assessment has been used as the standard to evaluate turf response to management practices and treatments. This method is subject to bias due to personal perceptions and visual preferences. In addition, the cause of stress cannot be readily determined by visual inspection. In this research, multispectral radiometry was used as an alternative method of rating visual quality. The seasonal vegetation trend was observed using visual assessment and vegetation indices, response to nitrogen application, effect of mowing practice, and response to irrigation methods (subsurface drip irrigation and sprinkler irrigation) of bermudagrass turf were investigated. Vegetation indices (NDVI, RVI, and SDI) correlated well with visual quality ratings (r 2 = 0.73, r 2 = 0.71, and r 2 = 0.70, respectively; P = 0.05). Mowing practice affected the spectral response in most wavelengths, increasing values between 3% and 4% in the visible and midinfrared ranges. Wavelengths in the nearinfrared range were not affected. In contrast, values for vegetation indices decreased as a result of mowing practices.

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