为探寻干旱半干旱区棉花微咸水膜下滴灌灌溉制度,在南疆地区开展了田间试验,对比分析了水分胁迫及盐分胁迫处理棉花的产量及长势,探讨了膜下滴灌条件下棉花对水盐胁迫的响应。试验采用WDY-500A微电子叶面积测量仪测定叶面积,并进行人工测产,采用原子吸收仪和滴定法测定土壤盐分。结果表明,轮灌处理A(苗期灌淡水)产量最高,为5 427kg/ha,其次是处理C(花铃前期灌淡水),为4 819.5kg/ha;棉花生育期对水分亏缺的敏感性为:花铃前期〉蕾期〉花铃后期;对盐分胁迫的敏感性为:苗期〉蕾期〉花铃前期〉花铃后期;灌水总量越大,棉花株高越高,叶面积指数也越大;某时段出现水分亏缺,该时段株高和叶面积指数增长幅度减小;越早给棉花灌溉淡水,棉花株高越高,叶面积指数越大;膜下滴灌条件下,淡水灌溉可以有效淋洗棉花根区土壤多余盐分,保证土壤环境安全,但是微咸水灌溉对棉花根区盐分淋洗效果不佳,且对土壤环境有一定的危险性,需在适当时期(如非生长期)采用较大灌水定额洗盐。
Field experiments were carried out in Xinjiang area to find proper program of drip irrigation under mulch for cotton in arid-semiarid area.Cotton growth and yield were measured and analyzed for discussing the effect of deficit irrigation and irrigation water salinity on cotton.In this paper,the leaf area,cotton yield and soil salts were measured by WDY-500A micro-electron leaf area,artificial method,atomic absorption spectrometer and titration,respectively.The results show that: the cotton yield of treatment A(irrigation with fresh water in seeding stage) was the highest,5 427 kg/ha;and the cotton yield of treatment C(irrigation with fresh water in early flowering-belling stage) was next below A,4 819.5 kg/ha;the sensitivity of cotton growth stage to deficit irrigation was: early flowering-belling stagebudding stageterminal flowering-belling stage;the sensitivity of cotton growth stage to irrigation water salinity was: seeding stagebudding stage early flowering-belling stageterminal flowering-belling stage;the cotton height and LAI increased with irrigation water quantity;the cotton height and LAI increasing scope reduced as deficit irrigation;the higher cotton height and the larger cotton LAI were observed the earlier irrigation with fresh water;in the condition of drip irrigation under mulch,fresh irrigation could leach extra soil salinity in root zone to make sure a safe soil environment,but saline irrigation could not leach extra soil salinity in root zone well that was dangerous to soil environment.Therefore,leaching extra soil salinity was necessary during proper timing(e.g.out of growth season).