Remote sensing of St. Augustine decline (SAD) disease /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
[College Station, Tex.] :
Odle,
1976.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy Link to ProQuest copy |
| Abstract: | Laboratory and field spectral reflectance measurements of healthy and SAD-infected St. Augustine grass were made using several different instruments. Spectral differences between healthy and infected grass occurred in the visible (0.38 - 0.70 μm) and near infrared (0.70 - 1.30 μm) regions. Multiband and color infrared photographs were taken of healthy and diseased turf from ground-based platforms and low altitude aircraft. Qualitative (density slicing) and quantitative (transmission densitometry) analyses revealed distinct tonal differences between healthy and SAD-infected grass. Similar experiments were done to determine if healthy and diseased grass could be distinguished from waterstressed grass and grass deficient in either nitrogen or iron. Using spectral reflectance measurements and photographic techniques, healthy grass could be distinguished from SAD-infected, nutrient deficient and water-stressed grass. However, these techniques were not adequate to distinguish the various stress factors from one another. Outdoor reflectance measurements in four broad spectral bands were made from container-grown plants using an ERTS-band radiometer. A computerized, pattern recognition analysis, known as transformed divergence, was carried out using reflectance data from various two-band combinations to determine the ability to discriminate among different treatments. Results showed a discriminability of over 90% for healthy and diseased grass. Unlike photographic techniques, this analysis also indicated a high percent discrimination for non-infected and infected grass in the presence of nutritional deficiencies and water stress.. |
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| Item Description: | Vita. "Major subject: Plant Pathology." |
| Physical Description: | xiv, 165 leaves : illustrations ; 28 cm |
| Bibliography: | Includes bibliographical references (leaves 157-164). |