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| DOI：10.13522/j.cnki.ggps.20180021 |
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| Estimating Water Content of Winter Wheat Canopy Based on Its Spectral Characteristics |
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Habure, ZHANG Baozhong, LI Sien, PENG Zhigong, HAN Nana, LIU Lu
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1. China Agricultural University, Beijing 100083, China; 2. China Institute of Water Resources and Hydropower Research, Beijing 100038, China; 3. Beijing Forestry University, Beijing 100083, China
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| Abstract: |
| 【Objective】 Knowing the change in water content of crops is imperative in agronomical management, and the purpose of this paper is to present a quick yet accurate method to diagnose real-time dynamics of water content of winter wheat canopy. 【Method】 We used high spectral sampling data measured from a winter wheat field in Daxing District of Beijing. The spectral characteristics of the canopy under different water conditions were analyzed. The spectrum band sensitive to water was screened and a diagnosis model was developed to estimate the canopy water content.【Result】①During the jointing-heading and the heading-milk-filling stages, the spectral reflectance of the canopy in wavelength of 750~1 075 nm near the infrared reflection increased with canopy water content, while during the milk-filling-mature stage the spectral reflectance of the canopy in the visible wavelength of 350~750 nm decreased as the canopy water content increased. ②The canopy water content during different growth periods of the crop was related to the wavelength in the range of 650~775 nm, with wavelength of 661 nm and 771 nm most sensitive. ③We presented an regressive model to link the sensitive band on the canopy water content.【Conclusion】When using the spectral technology to monitor canopy water content of winter wheat, the regressive model using the wavelength of 661 nm and 771 nm is most accurate. |
| Key words: spectrum; water content of plants; sensitive band; spectral characteristic parameter; moisture |
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