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| DOI： |
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| Threshold Drought and Flooding at Critical Growth Period of Winter Wheat in the Upper Reach of Huai River |
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YIN Zhouxiang, GAO Chao, LI Xuewen, RUAN Tian
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College of Territorial Resources and Tourism, Anhui Normal University, Wuhu 241000, China;Climate Change and Water Resource Center of Jiang-Huai Basin, Anhui Normal University, Wuhu 241000, China; Department of Geography & Spatial Information Techniques, Ningbo University, Ningbo 315211, China
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| Abstract: |
| Using the precipitation measured daily from 1961—2015 at 13 weather stations in the upper reach of Huai River, we calculated the monthly average and quarterly average SPI of winter wheat during its main growing season (February to March) respectively. Based on the harvest time, we calculated the yield loss rate due to the occurrence of drought and/or flooding in different growing stages, from which we analyzed the spatial distribution and variation of the precipitation, flooding and drought, as well as their relationship with the SPI. The results showed that there was a close correlation between SPI3 for critical growing stage and the SPI for April (SPI4), which passed both the 0.01 and 0.05 confidence tests. The precipitation during the two periods decreased, and there was a difference in the spatial distributions of the drought and flooding as well. The threshold at which a drought could cause agricultural loss was when SPI3 was -2.23 and SPI1_4 was -1.82. The correlation coefficients of SPI3 and SPI1_4 with the agricultural loss rate were 0.94 and 0.82 respectively, and there was a linear relationship between SPI and agricultural loss rate in typical flooding years. |
| Key words: SPI; winter wheat; growth critical period; threshold of drought and flood disaster; upper reaches of Huaihe River |
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