探索涝渍连续抑制天数指标作为水稻排水标准的试验

为探索涝渍连续抑制天数指标作为水稻排水标准， 通过测坑模拟水稻抽穗开花期涝渍连续动态试验，构建了水稻涝渍连续抑制天数指标（Continuous Stress-Day Index of Water Logging，CSDI）的模型，提出了CSDI和涝害权重系数的求解方法，通过对实测数据的分析，建立了水稻相对产量与CSDI的关系模型。研究结果表明:单纯受渍和涝渍连续灾害均会造成水稻不同程度的减产，但涝渍连续灾害减产程度比单纯受渍高；涝害权重系数是一个随涝渍状态变化而变化的状态变量；在涝渍连续情况下，水稻的相对产量与CSDI具有良好的线性关系，涝渍连续抑制天数指标可作为水稻排水设计标准。利用文中CSDI的模型，可制定水稻控制排水策略。

Experimental study of continuous stress-day index of water logging and excessive soil water as drainage standard of rice paddy fields

To explore the possibility of using the Continuous Stress-Day Index (CSDI) of waterlogging and excessive soil water as a drainage standard for rice paddy fields, consecutive and dynamic experiments on waterlogging and excessive soil water are conducted in testing pits during the heading and flowering stage of paddies. An CSDI model is developed to deal with waterlogging and excessive soil water issues. The model solution and the weight coefficient of waterlogging (C_W) are provided. The relationship of rice yield and CSDI is established through the analysis of experimental data. Results show that the stress and continuous stress from surface and subsurface waterlogging can reduce the rice yield in various degrees. The degree of yield-reduction is relatively high due to the continuous stress from surface and subsurface waterlogging. The weight coefficient C_W is a state variable that varies with the status of surface and subsurface waterlogging. A linear relationship between relative rice yield and CSDI can be observed under the condition of continuous stress from surface and subsurface waterlogging. Thus, the index CSDI can be utilized as a drainage standard for paddy fields, and the controlled drainage rules could be developed using the CSDI model.