调亏灌溉对棉花生长、生理及产量的影响

通过盆栽试验在棉花不同生育时期进行不同程度的调亏灌溉试验。结果表明,调亏灌溉对棉花株高、蕾铃脱落、成桃数等影响较显著;苗期和吐絮期重度水分亏缺、蕾铃期中度水分亏缺均有利于棉花产量的形成。棉花的光合速率和气孔阻力随土壤含水量变化的阈值约在14％土壤含水量水平,该阈值相当于田间持水量的60％～65％。合理的棉花调亏灌溉制度是苗期控制水分供应,土壤含水量维持在田间持水量的55％～60％;蕾期和花铃期是棉花的需水关键期,土壤含水量应分别保持在田间持水量的65％和70％左右;吐絮期应控制水分供应,土壤含水量维持在田间持水量的50％～55％。

Effects of water deficit on cotton growth,physiology and yield

Results of pot experiments showed that water deficit affected the height, buds, bulls falling and quantity of productive bulls of cotton. Severe water deficit at seedling stage and wadding stage ,medium water deficit at buds and bolls stage can be propitious to cotton yield. The threshold value of soil water contents for photosynthesis and stomatal resistance is about 14％ (0g) ,i. e. , 60％～65％ of field capacity. The lower limits of soil moisture for rational deficit irrigation scheduling to cotton at its different growth stages are 55％～60％, 65％, 70％ and 50％～55％ of field capacity at seedling, buds ,bolls and wadding stages, respectively.