微咸水灌溉对土壤水盐分布及冬小麦生长的影响

水资源短缺成为制约黄河三角洲地区社会经济发展的主要瓶颈和突出问题,合理开发利用该区的地下微咸水资源,利用微咸水进行农田灌溉已成为缓解该区域水资源短缺的重要策略之一。以黄河三角洲盐渍化典型地区为例,通过野外田间灌溉试验探讨了微咸水对土壤水盐分布特征及冬小麦生长、产量、光合作用特性的影响,并提出了土壤水盐调控措施。结果表明:(1)冬小麦生长期微咸水灌溉(淡水-微咸水-微咸水组合灌溉)增加了试验田土壤的含盐量,特别是表层0—20cm增加量达0.9g/kg;随后的雨季降水使土壤盐分得到淋洗进而避免盐分过多积累,至下一季冬小麦播种前0—20cm土壤盐分增加量减至0.12g/kg;(2)受微咸水灌溉的影响,冬小麦灌浆期的蒸腾速率显著下降(p0.05),但光合速率和气孔导度等差异不显著(p0.05);(3)微咸水灌溉和淡水灌溉的冬小麦产量分别为9 767,10 455kg/hm~2,微咸水灌溉下冬小麦略有减产,但无显著性差异(p0.05),千粒重均为44.9g,2种灌溉条件下冬小麦生长期的叶面积指数和叶绿素含量差异不显著(p0.05)。在当地淡水资源短缺的情况下,可以考虑使用3g/L的微咸水与淡水进行合理的组合灌溉,节约淡水资源,具有较好的社会经济效益,但从微咸水长期安全使用和土壤可持续利用来讲,需要采取一定的水盐调控措施并长期监测土壤盐分动态。

Effects of Brackish Water Irrigation on Water-salt Distribution and Winter Wheat Growth

The shortage of water resources has become the main bottleneck for social and economic development in the Yellow River Delta area,thus rational exploitation and utilization of brackish water resources is an important strategy to alleviate the shortage of water resources in this area.In this paper,taking a typical area of the Yellow River Delta as an example,soil water and salt distribution characteristics and the influence of the irrigation method using fresh water and brackish water on the growth and yield of winter wheat were investigated,and some control measures of soil salt accumulation were also put forward.The results showed were as follows:(1) Brackish water irrigation increased the total salt content of the soil in the experimental plot,especially in the 0-20 cm soil layer (increment 0.9 g/kg),and the amount of salt accumulation became smaller with the increase of the depth.Plenty of rainfall in the rainy season could make the soil salinity leaching into deeper soil layer and thus avoiding excessive salt accumulation after winter wheat harvest.Salt content increment in the 0-20 cm soil layer decreased to 0.12 g/kg at the period of next winter wheat sowing.(2) Photosynthetic rate and stomatal conductance of winter wheat were not significantly decreased under the influence of brackish water irrigation,while significant difference in transpiration rate was observed.(3) There was no significant difference (p ＞ 0.05) in the yield of winter wheat between the two irrigation methods using brackish water (9 767 kg/hm2) and fresh water irrigation (10 455 kg/hm2).A large amount of fresh water resources were saved,which could result in social and economic benefits.The study can provide a scientific reference for scientific and safe use of brackish water in the study area.