2005 Fiscal Year Final Research Report Summary
Development of the Water Stress Diagnostic Technology of the Citrus using Spectral Measurement and Granier Method
| Project/Area Number |
16580205
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Agricultural environmental engineering
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| Research Institution | Yamaguchi University |
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Principal Investigator |
YAMAMOTO Haruhiko Yamaguchi University, Faculty of Agriculture, Professor, 農学部, 教授 (40263800)
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| Co-Investigator(Kenkyū-buntansha) |
OTSUKI Kyoichi Kyushu University, Faculty of Agriculture, Professor, 大学院・農学研究院・森林資源科学部門, 教授 (80183763)
MORINAGA Kunihisa National Agricultural Research Center for Western Region, The 2nd team of general research, Director, 近畿中国四国農業研究センター・総合研究部総合研究第2チーム, チーム長 (90414789)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Spectral Measurement / Granier Method / Citrus / Water Stress / Near Infrared Measurement / Transpiration flow rate / Leaf Area Index / Digital image |
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| Research Abstract |
In this study, water stress diagnostic technology of the citrus using spectral measurement and Granier method was developed. The commercial sensor was selected as one that can measure soil moisture inexpensively and quickly at field experiment. Very high correlation (r=0.897) was acquired between the total leaf area calculated from the half-ellipse model, and the total leaf area obtained by counting the number of total leaves. The technology of estimating the total leaf area by non-contact and non-destructive method with high precision was developed using the inexpensive digital camera with a fish-eye lens. Moreover, we used the Granier method and tried measuring the transpiration flow rate of the citrus tree under the mulch-cultivation. Consequently, it was shown clearly that the soil dryness by rain interception of white mulch sheet gives dryness stress to a tree, and reduces the transpiration flow rate. Furthermore, the non-destructive technique of estimating the leaf water potential of a citrus leaf was examined using near infrared spectral analyzer. In PLS regression analysis of the eight main ingredients which calculated from the all of 1,061 measurements at each wavelength (1300-2400nm), the high prediction accuracy of R=0.817, difference SEP=0.300MPa, and Bias=0.004MPa was acquired. From this, it became clear that the water potential of a citrus leaf could be estimated by non-destructive method using an infrared spectrum method.
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Research Products
(14 results)
