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| DOI： |
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| Impact of Different Irrigation Methods on Resistance of Rice Against Bending and Breaking |
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GUO Xiangping, HUANG Shuangshuang, WANG Zhenchang, WANG Fu, CHEN Bin
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College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China
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| Abstract: |
| The impact of four irrigation methods - deep flooding irrigation (FI), frequent-shallow irrigation (DSI), controlled irrigation (CI) and rain-capture and controlled irrigation (RC-CI) -on resistance of rice against bending and breaking was investigated experimentally in this paper. The results showed that in comparison with the traditional flooding irrigation (CK), the two water-saving irrigation methods (CI and RC-CI) ①significantly increased (P＜0.05)the diameter, wall thickness and cross section of the rice stem, ②increased the plumpness and decreased the length of the first and second intermodal stems. Compared with FI, CI and RC-CI increased the breaking-resistance (BR) by 32.58% and 43.69% respectively, and the bending moment (BM) by 8.04% and 9.64% respectively, leading to an increase in lodging index LI (LI= BM/BR) by 18.60% and 23.60% respectively. Compared with FSI, BR under CI and RC-CI increased by13.48% and 22.99% respectively, whereas their associated BM increased only by 0.42% and 1.91% respectively, leading to a decease in LI by 14.54% and 17.08% respectively. The two water-saving irrigation methods increased the accumulation of dry matter androot-shoot ratio in comparison with CK. Compared with FI, CI and RC-CI increased the ratio of stem-sheath dry matter to above-ground dry matter by 8.16% and 9.00% respectively, whereas decreased the ratio of panicle dry matter to above-ground dry matter by 4.03% and 4.27% respectively. Compared with FSI, CI and RC-CI increased the ratio of stem-sheath dry matter to above-ground dry matter by 2.56% and 3.32%, while decreased the ratio of panicle dry matter to above-ground dry matter by 2.29% and 2.53%, respectively. The root - shoot ratio and the ratio of stem-sheath dry matter to above-ground dry materswere negatively correlated with LI (P＜0.01), while the ratio of panicle dry matter to above-ground dry matter was positively correlated with LI (P＜0.05). BR and BM under RC-CI increased slightly in comparison with those under CI, and there was no significant difference in LI between the two irrigation methods (P＞0.05). |
| Key words: rice; irrigation method; lodging resistance; lodging index |
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