Study on irrigation scheduling of cotton under mulch drip irrigation with brackish water

In order to obtain the optimal irrigation program of mulch drip irrigation with brackish groundwater, the growth and yield of cotton under 11 different irrigation treatments in 2008 and 2009 were analyzed in different reproductive periods. In this paper, the leaf area, dry matter, cotton yield and salt of soil were measured by WDY-500A micro-electron leaf area, oven drying method, artificial method, atomic absorption spectrometer and titration, respectively. These results showed the cotton vegetative growth became faster with increase of irrigation water; the proportion of reproductive growth was greater and easier to become old when the salinity of irrigation was higher. These results also indicated that rotation irrigation system (3 750 m3/hm2, 80% brackish water and 20% fresh water) was the optimal one, whose yield reached 5 190 kg/hm2. Meanwhile, in 2008 the rotation irrigation system attained a negative growth (-0.95 g/kg) of total salt. And results of 2009 strongly demonstrated the superiority of the irrigation system. This rotation irrigation system will realize water conservation, increasing yield effectively and protection of soil environment