地下水浅埋区重度盐碱地覆膜咸水滴灌水盐动态试验研究

Water and salt dynamics of saline-sodic soil with shallow water table under mulch-drip irrigation with saline water

摘要:

通过在高垄埋设水银负压计，研究土壤水势动态，并在枸杞不同生育期对潜水位以上各土层盐分进行取样分析，研究土壤盐分周年动态变化，为地下水浅埋区重度盐碱地改良利用提供理论依据。试验结果表明在覆膜滴灌一个灌溉周期内，土壤水分运动始终为自滴头下方饱和区持续径向向外扩散；雨季降雨使水分从土壤剖面整体向下运动，随着潜水位的升高水分运动逐渐减弱，转为自垄中部向垄坡方向运动。盐分运动受水分运动影响明显，周年盐分动态可以分为春季强烈蒸发——积盐阶段；灌溉淋洗——稳定阶段；雨季淋溶——脱盐阶段；秋季蒸发——积盐阶段和冬季相对稳定阶段五个阶段，剖面土壤电导率(EC1:5)均值从1.64 dS ^-m增长至1.69 dS ^-m，土壤未明显积盐。盐分的剖面分布表明滴灌灌溉调控了水分盐分在土壤中的分布，为作物根系生长提供了良好的土壤环境条件，因此，地下水浅埋区重度盐碱地可以利用高垄覆膜咸水滴灌技术加以利用。

Abstract:

To provided the theory basis for the reasonable exploitation and sustainable utilization of saline-sodic soil with shallow water table, soil water potential was observed by tensiometer and, according to different growth periods of Fructus Lyeii, soil above water table was sampled in each layer to study the annual dynamic changers of soil salt. The results showed that water was kept infiltrating radially from the dripper till the next irrigation; during the rainy season, rainwater moved from the upper layer to the deeper and slowed down while water table rose up; soil water than moved from the middle of the bed to the slope. Salt movement was obviously affected by water movement and it can be divided into five stages in a year: evaporation in spring-salt accumulated stage; leaching by irrigation-salt stabilized stage; leaching by rainfall-desalinized stage; evaporation in autumn-salt accumulated stage and relatively stable stage in winter. At the experiment field, after mulch-drip irrigation for a year, salt accumulated insignificantly and EC1:5 of the bed varied from 1.64 dS ^-m to 1.69 dS ^-m. The distribution of salt in transect indicated that soil salt was regulated by mulch-drip irrigation and suitable soil environment was provided for root growth, so the saline-sodic soil with shallow water table can be utilized by mulch-drip irrigation with saline water.