Effect of drip irrigation pattern and irrigation lower limit on yield and quality of cotton

To explore the high-quality irrigation index of cotton under drip irrigation,a field experiment was conducted to investigate the effects of different irrigation lower limits on seed cotton yield,fiber quality and water use efficiency of cotton under subsurface drip irrigation with film mulching( SSDI) and surface drip irrigation with film mulching( SDI) in Shihezi,Xinjiang Autonomous Region.The results show that water consumption during squaring stage increases with irrigation lower limit rising,and the water consumption of water deficit treatments during blooming-boll forming stage are lower than control experiment. It is beneficial to improve seed cotton yield under moderate water stress( 60% FC) during squaring stage and no water stress( 75% FC) during blooming and boll forming stage( SDI- 7 and SSDI- 7),and comparing to the control treatment,seed cotton yield is improved by 14. 48%( SDI- 7) and 11. 60%( SSDI- 7). Water treatments has no obvious influence on lint percentage and uniformity of cotton fiber,and the effect of water stress on length of cotton fiber during squaring stage and blooming-boll forming stage increases with irrigation lower limits decreasing. Moderate water stress at squaring stage can increase the breaking tenacity of cotton fiber. Compared with surface drip irrigation under film mulching,subsurface drip irrigation can improve seed cotton yield and irrigation water use efficiency of cotton at the same water treatment. This research suggests that the irrigation model with 30 mm of irrigation water quota and irrigating at lower limits of 60% FC and 75%FC during the squaring stage and flowering-boll forming stage,respectively,can be taken as suitable irrigation index of drip irrigation cotton to save irrigation water,to increase seed cotton yield and to improve cotton fiber quality in Reclamation Area of Shihezi,Xinjiang Autonomous Region.