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| DOI：10.13522/j.cnki.ggps.20190195 |
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| Estimating Daily Water Requirement of Rice in Huaibei Region Using Temperature Difference between Canopy and Ambient Air |
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XU Liehui, MOU Hanshu, WANG Jingcai, ZHOU Mingyao
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1.College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou 225009, China；2. Huai’an Water Conservancy Bureau, Huai’an 223005, China
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| Abstract: |
| 【Objective】Understanding the change in demand of crop for water is essential to improving irrigation management, and the purpose of this paper is to verify the feasibility of using temperature difference between rice canopy and its ambient air to estimate its water requirement.【Method】The experiment was conducted in lysimeters at the Huailian Irrigation Districts in Huaibei Region, and the daily water requirement of the rice was obtained by weighing the lysimeters. We also measured the temperature in the rice canopy and its ambient air concurrently. A model using solar net radiation and canopy-air temperature difference to estimate the daily rice water requirement was presented, with its results further modified by the leaf area index.【Result】The solar net radiation and the canopy-air temperature difference were two key factors affecting water requirement of the rice, with the former impacting on the water requirement negatively and the latter positively; the canopy-air temperature difference appeared to increase as the crop grew. The relative error of the model after modification by the leaf area index was 5.07%, and its associated root mean square error was 0.183 mm/d.【Conclusion】Estimating daily water requirement of rice using canopy-air temperature difference is simple and the results could meet the requirement of irrigation management. |
| Key words: canopy-air temperature difference; daily water requirement of rice; leaf area index; modification by leaf area index. |
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