Research on the Criteria of Farmland Drainage under the Influence of Combined Controlling of Surface and Subsurface Water Logging in Several Phases of Cotton

Trough two years (2003～2004) experimentation on combined controlling of surface and subsurface water logging in cotton, the indexes of combined controlling of surface and subsurface water logging in several phases of cotton and the related crop water production functions were studied in this paper; Based on the analysis of the data of two years, it can be found that the correlation of crop yield and the indexes of combined controlling of surface and subsurface water logging is very satisfied. The sensitivity in four phases of cotton is ranked, which is helpful for the design and for operation maintenance of the drainage project for the combined controlling of surface and subsurface water logging.