干旱区棉花水分胁迫指数对滴灌均匀系数和灌水量的响应

Response of crop water stress index to drip system uniformity and irrigation amount in arid regions

为了修订和完善滴灌均匀系数的设计与评价标准，在新疆干旱区研究了滴灌均匀系数和灌水量对作物水分胁迫指数（CWSI）的影响。供试作物为棉花，试验中滴灌均匀系数（Cu）设置0.65（C1）、0.78（C2）和0.94（C3）三个水平，灌水量设置充分灌水量的50%、75%和100%三个水平。结果表明：棉花冠层温度和CWSI表现出随灌水量增加而降低的趋势；冠层温度和CWSI均匀系数的变化范围分别为0.91～0.98和0.65～0.91，均随滴灌均匀系数增加而增大；灌水量对冠层温度和CWSI均值的影响达到极显著水平（α=0.01），滴灌均匀系数对冠层温度和CWSI均匀系数的影响达到显著水平（α=0.05）或极显著水平。CWSI与皮棉产量呈显著或极显著的负相关关系；滴灌均匀系数越低，水分亏缺引起的减产幅度越小。

The effects of drip system uniformity and irrigation amount on the crop water stress index （CWSI） were evaluated in arid environments of Xinjiang Uygur Autonomous Region, China, during the growing season of cotton in 2011 to amend the current design and evaluation standards of drip system uniformity. Three Christiansen uniformity coefficients （Cu） of 0.65, 0.78, and 0.94 and three irrigation levels of 50%, 75%, and 100% of full irrigation were used. A higher irrigation amount resulted in a lower canopy temperature and CWSI. The uniformity coefficients of canopy temperature and CWSI, which ranged from 0.91 to 0.98 and 0.65 to 0.91, respectively, were positively correlated with the drip system uniformity. Irrigation amount had a significant effect on canopy temperature and CWSI at the 0.01 level. The influence of drip system uniformity on the uniformity coefficient of canopy temperature and CWSI were significant at the 0.05 or 0.01 level. A significantly negative correlation between lint yield and CWSI was observed. The reduction of lint yield caused by water stress for the low uniformity treatment was lower than that for the high uniformity treatment.