宁夏平罗县井渠结合灌区地下水盐运移规律研究

以综合治理井渠结合灌区土壤盐碱化为目标,针对宁夏平罗县井渠结合灌区下游灌水难、排水难和盐碱化严重等问题,采用渠灌井排、井沟联合使用等措施,对作物进行适量和适时灌溉,充分利用地下水资源,并监测井渠结合灌溉条件下田间土壤含盐量、地下水矿化度和水位埋深的变化情况,分析地下水埋深和矿化度对土壤含盐量的影响。结果表明:井渠结合灌溉对降低地下水位效果显著。以黄河水为主要灌溉水源的宁夏银北自流灌区,地下水矿化度变化幅度较小;灌溉后的土壤表层含盐量骤降,0~40 cm土层的盐分变化较大;土壤盐分与地下水矿化度具有较强的线性正相关性,与地下水埋深呈负相关。研究成果对干旱半干旱区灌区水资源优化配置、盐碱地改良具有参考价值。

Study on law of groundwater salt transportation in Pingluo Well Canal Combined Irrigation District in Ningxia

By taking the soil salinization control of the well canal combined irrigation district as the study case and aiming at the problems of difficult irrigation， difficult drainage， serious salinization， etc. from the Pingluo Well Canal Combined Irrigation District in Ningxia， the measures of canal irrigation and well drainage， combined use of well and ditch， etc. are adopted to fully utilize the groundwater for the irrigation with proper amount and proper time， while the variations of the total salinity of soil in farmland， the mineralization of groundwater and the groundwater level depth under the condition of well canal combined irrigation are monitored， and then the impacts from both the groundwater level depth and the salinity of soil are analyzed as well. The result shows that the effect from the well canal combined irrigation on lowering groundwater level is significant. So far as the North Yinchuan Gravity Irrigation District， for which the irrigation water source is mainly relied on the water from the Yellow River， is concerned， the amplitude of variation of the mineralization of groundwater is smaller， the total salinity of the surface soil is suddenly lowered with larger variation of salinity in the soil layer of 0~40 cm， while the soil salinity has a stronger linear positive correlation to the mineralization of groundwater and a negative correlation to the groundwater level depth. The study result has reference value for the optimal allocation of water resources and improvement of saline land for the irrigation district within arid and semiarid region.