咸淡水组合灌溉对土壤盐分和棉花生长的影响

Effects of Combined Saline Water and Freshwater Irrigation on Soil Salinity and Cotton Growth

为揭示不同微咸水(农田排水)与淡水在“先咸后淡”的组合灌溉模式下对土壤容重、盐分迁移和棉花生长的影响。以淡水灌溉为对照(CK),设置7种不同微咸水、淡水组合灌溉(微咸水∶淡水=1∶14(T1)、2∶13(T2)、3∶12(T3)、6∶9(T4)、9∶6(T5)、12∶3(T6)),T7处理采用全额微咸水灌溉,于2022年4-9月进行了棉花田间试验。结果表明,采用微咸水灌溉造成土壤表层盐分积累,0~40 cm土层出现积盐现象,棉花生育期结束后,各处理与淡水对照(CK)比较,T1~T6在0~40 cm土层的电导率分别增加1.16%~26.61%,T7处理电导率增加86.40%;与淡水对照相比,组合灌溉后各处理土层0~40 cm土壤容重明显增加,土壤孔隙度降低,以全额微咸水灌溉T7处理最为显著(容重增加10.24%);微咸水组合灌溉有效提高棉花株高、叶面积指数、茎粗。合理利用微咸水组合灌溉能够为棉花生长提供良好的水盐环境,提高棉花产量,能够为极端干旱区合理利用微咸水提供一种新的灌水模式,为灌区发展节水灌溉及农业可持续发展提供理论支撑。

In order to investigate the effects of different radios of brackish water(farmland drainage)to fresh water in a"saline first,then fresh"combined irrigation mode on soil bulk density,salt migration,and cotton growth.With fresh water irrigation as control(CK),we established 7 different irrigation treatments combining brackish water and fresh water.The radios of brackish water to fresh water were set as follows:1∶14(T1),2∶13(T2),3∶12(T3),6∶9(T4),9∶6(T5),12∶3(T6).Additionally,the T7 treatment received irrigation with full brackish water.Cotton field trials were conducted from April to September 2022.The results showed that salt accumulation occurred in the soil layer of 0~40 cm due to brackish water irrigation.After the growth period,compared with the fresh water control(CK),the electrical conductivity of T1~T6 in 0~40 cm soil layer increased by 1.16%to 26.61%,while the T7 treatment experienced a substantial increase of 86.40%.Compared with the fresh water control,the bulk density of 0~40 cm soil layer in the combined irrigation increased significantly and the soil porosity decreased,and the bulk density increased by 10.24%in theT7 treatment.Brackish water combined irrigation can effectively improve cotton plant height,leaf area index,and stem diameter.Rational utilization of brackish water combined irrigation can provide a good water-salt environment for cotton growth,improve cotton yield,provide a new irrigation model for rational utilization of brackish water in extreme arid areas,and provide theoretical support for the development of water-saving irrigation and sustainable agricultural development in irrigation areas.