微咸水膜下滴灌对棉花生长发育及其产量的影响研究

Effect of Mulched Drip Irrigation with Saline Water on Cotton Growth and Yield

微咸水膜下滴灌是缓解全球农业用水短缺的有效途径之一。通过开展不同灌溉水矿化度条件下的农田控制试验,围绕微咸水膜下滴灌对棉花叶面积、地上生物量积累及其分配、棉株叶片含水率、棉花产量及产量构成因素等的影响进行了研究,同时结合Logistic模型,对地上干物质积累规律进行了探讨。结果表明:利用矿化度低于6.0g/L的微咸水膜下滴灌比淡水灌溉更有利于棉花叶面积的生长;微咸水矿化度在2.0g/L时会促进棉花干物质的积累,而当矿化度≥4.0g/L时,干物质积累量随着矿化度的增加而减少,矿化度的增加会使干物质快速积累起始时间推迟且持续时间缩短。当矿化度≤4.0g/L时,棉花生育后期生殖器官所占比重随灌水矿化度的增加而增大,但当矿化度达到6.0g/L时生殖器官所占比重减小;灌溉水矿化度对棉花产量的影响有明显的分段性,民勤绿洲区种植棉花的灌溉水矿化度阈值为3.51g/L,即在矿化度<3.51g/L时,微咸水灌溉的棉花产量与淡水灌溉产量差异不明显,高于此阈值时,则会造成减产。

Mulched drip irrigation with saline water is an effective method to relieve global agricultural water scarcity.A field experiment under different irrigation water salinity was conducted to study the effect of mulched drip irrigation with saline water on cotton leaf area index,aboveground biomass and its allocation,cotton leaf water content,yield and its component.The Logistic model was also used to analyze the regularity of dry matter accumulation.The results demonstrated that the use of brackish water film salinity below 6.0g/L under drip irrigation was more conducive to the growth of cotton leaf area than fresh water irrigation;the dry matter accumulation of cotton increased while the total dissolved solid（TDS）of irrigation water was 2.0g/L.However,the value was reduced with TDS increase when the TDS was greater than 4.0g/L.In addition,the start time of quick accumulation was delayed and its duration was shortened.The proportion of reproductive organ during late growth stage increased when the TDS was less than 4.0g/L,and reduced when TDS was 6.0g/L.The effect of mulched drip irrigation with saline water on cotton yield had obvious stages.The threshold of irrigation water TDS in Minqin Oasis was 3.51g/L：when the TDS was less than this value,there was no significant difference in cotton yield between saline and fresh water irrigation,while TDS is bigger than this threshold,the yield will decrease.