针对以往研究忽视雪被厚度、雪层密度等因素对水热间能量分配与转换的影响，难以充分发挥冻土蓄水保墒作用，将雪被、农田土壤及中间覆盖视为一个复合系统，运用复杂适应系统理论概化各子系统主体，确定其行为函数及行为参数，识别水热时空分异关键驱动因子，计算其综合驱动力指数，揭示水热时空分异驱动机制；进而建立不同覆盖条件下雪被-农田土壤复合系统水热联系方程，确定水热时空分异分析模式，建立适宜的水热时空分异指标、分异函数和分异模型，确定水热时空分异程度和时空结构性，揭示水热时空分异规律；最后，分析不同冻融期、不同覆盖及雪被厚度对土壤活动层水热过程的影响机制，建立系统互作效应函数，确定农田土壤墒情诊断关键影响因子，提出适宜的农田土壤墒情保持技术。研究成果为揭示雪被及覆盖条件下水热作用机理，解决雪被-农田土壤复合系统不同要素间"流"传递关系确定、水热时空分异模式识别和水热互作效应函数确定等问题具有重要意义。

Aiming at ignoring some factors like snowcover thickness and snowcover density to affect energy distribution and transformation between water and heat that leading to unfulfill the function of water conservation of frozen soil, snowcover, soil and coverage between them can be seen as a complex system. Firstly, the main part of each system can be generalized with the help of CAS theory, behavior function and behavior parameters can be fixed and the key driving factor, that its driving force comprehensive index can be calculated can be distinguished. Then the spatial-temporal variation feature of water and heat of snowcover-farmland combined system can be revealed. Secondly, through building the water and soil relation function of snowcover-farmland combined system on the condition of different cover, the spatial-temporal variation pattern of water and heat can be fixed and the variation index, variation function and variation model can be built, and then the spatial-temporal variation degree and spatial-temporal designability can be fixed. The spatial-temporal variation law of water and heat of snowcover-farmland combined system can be revealed. Finally, the influence mechanism of different freeze-thaw period, different coverage and snow thickness to heat and water process of soil activities can be analyzed. Through building the system mutual impact function the key influence factor can be fixed, and then the technology of keeping farmland soil moisture content can be presented. The results have great significance for revealing water and heat action mechanism on the condition of snowcover and coverage and solving some problems, such as fixing "stream" transitive relation among different factors of snowcover-farmland combined system, distinguishing the spatial-temporal variation pattern of water and heat and fixing the water and soil relation function.