棉花调亏灌溉的生理响应及其优化农艺技术

在移动式防雨棚下，采用盆栽土培法和测坑微区试验相结合的方法，分析了调亏灌溉对棉花不同生育阶段蒸腾速率（Tr）、光合速率（Pn）、光合产物积累与分配、经济产量（Y）和水分利用效率（WUE）的影响，盆栽试验采用二因素（水分调亏阶段和调节亏水度）随机区组设计，测坑微区试验采用三因素（水分调亏度、施肥水平和植株密度）正交旋转组合设计。结果表明：适时适度的水分调亏使得Tr明显下降，而Pn下降不明显，复水后光合产物具有超补偿积累，且有利于向经济产品（籽棉）运转与分配。棉花调亏灌溉（RDI）的适宜指标是：苗期轻、中度调亏，0～40cm土层湿度下限为50％FC～60％FC（田间持水量）；蕾期轻度调亏，0～40cm土层湿度控制下限为60％FC；花铃期不宜调亏，0～40cm土层湿度应不低于75％FC；吐絮期可中度调亏，0～40cm土层湿度可控制在50％FC～55％FC。

Physiological responses of cotton to regulated deficit irrigation and its optimized agronomic techniques

Under the condition of mobile rain-proof shelter,combined pot experiment with the pond culture,the effects of regulated deficit irrigation(RDI) on the photosynthetic rate(Pn),transpiration rate(Tr),distribution and accumulation of photosynthetic products,economic yield and water use efficiency during the different growth stages of cotton were analyzed.A two-factor(RDI stages and the amount of water deficit) randomized-block design was adopted in pot experiment and a three-factor(the amount of water deficit,fertilizer level,plant density)quadratic rotational regression combination design was adopted in pond culture.Results show that under appropriate amount of water deficit at right stages,Tr decreases obviously,and Pn does not obviously decrease.There are super-compensation effects in photosynthesis and photosynthetic products accumulation after re-watering,which is beneficial for the translocation and distribution of seed cotton.The suitable indexes of RDI for water-saving and high-yield of cotton as follows: the regulated water deficit during seedling stages is low and moderate water deficit,and the amount of water deficit at 0~40 cm soil layer is 60?(field water capacity)~60?.Regulated water deficit during bud stages is low water deficit,and the amount of water deficit is 60?.During floweringboll forming stages,regulated deficit irrigation is not suitable,and the amount of water deficit is above 75?.Regulated water deficit during boll-opening stage is moderate water deficit,the amount of water deficit is 50?~55?.