咸水灌溉下塔里木沙漠公路防护林盐分平衡及盐分运移

Salt balance and movement of Tarim Desert Highway Shelterbelt irrigated by saline water

应用生态系统物流理论，把土壤-植物-大气作为一个完整的系统，将植物、土壤和地下水作为三个分室，建立分室流动模型，对植物和土壤间的盐分平衡进行定量研究，探索咸水灌溉条件下塔里木沙漠公路防护林盐分运动的规律。结果表明：塔里木沙漠公路防护林使用大量咸水灌溉后盐分并没有在根层土壤0～2m土层中累积，而是储藏在2m以下或渗漏到地下水。其中，0～2m土体盐储量减少125．1t，地下水位1．50m以上至2m土体盐储量增加79．9t，45．2t盐分重新回到地下水。根层土壤0～2m土层中土壤脱盐明显。灌溉后各土层的全盐量在0．5--0．9g／kg之间，远低于土壤原始全盐量1．47g／kg。这是咸水灌溉下植物能够正常生长的主要原因。研究对于确定塔里木沙漠公路防护林合理的灌溉制度及预测和评估该地区盐渍化的发生发展具有重要意义。同时，也为塔里木沙漠公路全线绿化和水分管理提供科学依据。

By applying the material flow theory of ecosystem, soil, plants and atmosphere are regarded as a integrate system and divided into three compartments, and flow model is established to study salt balance between plants and soil for exploring the law of salt movement of Talim Desert Highway Shelterbelt irrigated by saline water. The results show that salt doesn＇t accumulate within the depth of 0--2 m in soil around the root, but is stored below the depth of 2 m in soil and leak into underground water. Among them, the quantity of salt storage decrease 125.1 t within the depth of 0--2 m in soil around the root, the quantity of salt storage increase 79.9 t below the depth of 2 m in soil, and 45.2 t salt returns to underground water. The content of salt declines dis- tinctly within the depth of 0--2 m in soil around the root. The content of salt is 0.5--0.9g/kg and is less than the original one . This is main reason that plants irrigated by saline water can grow normally. The paper can supply important gist for the construction of Talim Desert Highway Shelterbelt to found suitable irrigation rule and evaluate the processes of soil saline - water - logging.