Pedosphere 11(3): 227--234, 2001
ISSN 1002-0160/CN 32-1315/P
©2001 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Study on intermittent irrigation for paddy rice: Ⅱ. Crop responses |
| LU Jun1, LIU Yun-Long1 and T. HIRASAWA2 |
1 Department of Natural Resources, Zhejiang University, Ha-on 510099 (China)
2 Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-85O9 (Japan) |
| ABSTRACT |
| Effect of intermittent irrigation on the production of paddy rice was studied in a well-puddled paddy field with four treatments and 2 replicates: continuous flooding irrigation (CFI), and intermittent irrigation Ⅱ-0, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigated when the soil water potential fell below 0, -10, and -20 kPa, respectively, at soil depth of about 5 cm. Results showed that the reduction in soil water potential to about -10 or -20 kPa did not significantly affect the number of grains and the percentage of ripened grains. While, a lower crop growth rate (CGR) resulted from a decrease in the net assimilation rate (NAR) during intermittent irrigation Ⅱ-1 and Ⅱ-2, and there was also a reduction in the leaf area index (LAI) during intermittent irrigation Ⅱ-2. Senescence of lower leaves on stems was promoted in treatments Ⅱ-1 and Ⅱ-2 at the ripening stage. Early senescence at ripening stage and water stress around midday decreased the rate of photosynthesis in leaves, causing the lower NAR. These physiological responses of the plants were responsible for the reduction in the dry matter production and grain yield in the intermittent irrigation treatments. |
| Key Words: crop growth rate, intermittent irrigation, net assimilation rate, paddy rice, yield components |
| Citation: Lu, J., Liu, Y. L. and Hirasawa, T. 2001. Study on intermittent irrigation for paddy rice: Ⅱ. Crop responses. Pedosphere. 11(3): 227-234. |
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