北方农牧交错带典型集约菜田蒸散及水盐运移过程研究

The intensive vegetable’s expanding in the Northern Farming-pastoral Ecotone (NFPE) during the past 20 years has changed the traditional agricultural irrigation and fertilizer, which lead to serious groundwater depletion and pollution, death of the shelter-forest and dries up of the playas. The evapotranspiration processes of vegetable crops, soil water and solute transport mechanism in the vadose zone and the effects of intensity on field water balance, soil water and solute transport are the basics of the water resources protection and ecology construction. The current proposed project will be implemented based on field experiments in the typical intensive vegetable field in the NFPE. The large-scale lysimeters, irrigation-leaching cells and HYDRUS-1D model will be employed in this research, to clarify the evapotranspiration processes and e evapotranspiration partition’s dynamics of the irrigated vegetables (Chinese cabbage, cabbage, lettuce and potatoes) and rainfed crops (spring wheat and oats). Then, explore the flux processes of water percolation and solute leaching, and simulate the historical characters of intensive vegetables’ evapotranspiration and vadose zone soil water and solute transport, in order to quantify the influences of intensive irrigation and fertilizer on accelerating the field water cycle, changing of evapotranspiration partition and increasing risks of groundwater pollution. This research will provide scientific ground for intensive agriculture’s field water and fertilizer management, and the regional sustainable water resources development policies in the NFPE.

近20年北方农牧交错带集约蔬菜的快速扩张打破了传统雨养农业的水肥模式，致使地下水超采、地下水污染、防护林死亡和湖泊干涸等生态问题日趋严重。明确集约蔬菜作物蒸散规律、解析菜田包气带水盐运移机理、评估集约化对传统农田水平衡及水盐运移的影响，是进行水资源保护和生态建设的基本前提。本项目以北方农牧交错带中部典型集约蔬菜种植区为研究区，依托大型蒸渗仪群、测坑群以及HYDRUS-1D模型，以传统雨养作物(春小麦和莜麦)为对照，阐明灌溉蔬菜(大白菜、甘蓝、莴笋及马铃薯)的蒸散过程与结构，解析包气带水盐运移过程及淋失通量变化机理，模拟近20年集约蔬菜的蒸散耗水与水盐淋失过程，定量评估农业集约活动对加速农田水循环、改变蒸散结构和包气带水盐运移过程的影响。研究成果可为北方农牧交错带集约农田的水肥管理、区域水资源可持续利用政策的制定提供科学依据。

近20年北方农牧交错带集约蔬菜的快速扩张打破了传统雨养农业的水肥模式，致使地下水超采、地下水污染、防护林死亡和湖泊干涸等生态问题日趋严重。明确集约蔬菜作物蒸散规律、解析菜田包气带水盐运移机理、评估集约化对传统农田水平衡及水盐运移的影响，是进行水资源保护和生态建设的基本前提。. 本研究以北方农牧交错带典型集约蔬菜和雨养裸燕麦为研究对象，按研究计划已完成项目计划书研究内容，主要包括：1）依托大型蒸渗仪明确了蔬菜作物蒸散过程及蒸散结构变化规律；2）通过对土壤水分及盐分的定期监测，并利用根区水质模型（Root Zone Water Quality Model2, RZWQM2）对硝态氮的渗漏过程进行了过程模拟，明析了菜田包气带水盐运移过程及盐分淋失过程；3）评价了集约化对蒸散耗水特征的影响，定量研究了集约化对包气带水盐运移过程的影响。. 研究成果可为北方农牧交错带集约农田的水肥管理、区域水资源可持续利用政策的制定提供科学依据。