黄土丘陵区不同植被土壤水热耦合与蓄持水能力的交互调控研究

The change of soil hydrothermal characteristics is closely related to vegetation restoration. To date, the associated studies on the mechanism of soil hydrothermal coupling under vegetation restoration on the Loess Plateau are mainly focused on the single factor, soil water or temperature, while the soil hydrothermal dynamic change and soil water reserving and holding capacity received less attention. This study intends to take the natural vegetation recovery sequence at Ziwuling in the Loess Hilly region as the research object, in combination with indoor simulation and location monitoring, to measure the soil water spatiotemporal change, explore the water consumption mechanism incorporation with precipitation during different vegetative period, analyze the spatiotemporal variation of soil temperature, and soil thermal conductivity and heat flux influenced by soil and meteorological factors, determine the interaction between soil water and soil temperature during vegetation restoration, and clarify the correlation between hydrothermal coupling and soil water reserving and holding capacity as well as the interactive regulation with them, the above research works would help to deepen the new understanding of soil “reservoir” with soil hydrothermal coupling and the soil water reserving and holding capacity during the vegetation restoration on the Loess Hilly region, provide scientific and practical basis for monitoring and assessing the vegetation restoration and soil and water conservation on the Loess Plateau.

土壤水热特征变化与植被恢复关系密切。迄今，有关黄土高原植被恢复的土壤水热耦合效应研究，多限于土壤水分或温度等的单一因素研究，而对不同植被土壤水热动态变化与蓄持水能力的研究亟待加强。本研究拟选择黄土丘陵区子午岭植被自然恢复序列，室内模拟与定位监测相结合，监测植被恢复过程中的土壤水分时空动态，结合降雨量，探究植被生育期内的耗水机制；测定土壤温度的时空变化，探究土壤和气象因子对土壤导热率和热通量的影响；确定植被恢复过程中土壤水分和土壤温度的交互作用关系，阐明土壤水热耦合与蓄持水能力的相关性及其交互调控机制，以丰富黄土丘陵区土壤水热耦合与蓄持水能力研究的土壤“水库”新理解，为黄土高原植被恢复和水土保持的监测评价提供科学与实践依据。

本研究以黄土丘陵区不同恢复植被为研究对象，通过多年连续测定植被生育期的土壤含水量，结合生育期内的降水量，分析植被、土壤深度和土壤物理化学性质等因子对土壤含水量的影响，并明晰其相关关系，揭示了土壤水分的时空变异机制，探究了不同植被生育期内的耗水机制；通过多年连续测定植被生育期的土壤温度，研究了黄土丘陵区自然植被恢复过程中的不同阶段的植被下的土壤温度的时空变化，明确了不同植被下土壤温度随土层深度和植被生育期的变化规律，明晰了植被、土壤颗粒组成和土壤孔隙度等因子对土壤温度的影响，结合气象因子对土壤导热率和热通量的影响，揭示了土壤温度的时空变异机制；通过测定黄土丘陵区自然植被恢复过程中的不同阶段的植被下的土壤的持水性和热特性，探讨了不同植被类型及粒径组成对土壤持水性和热特性的响应关系，结合原生境不同植被类型的土壤容重、孔隙度、导热率以及渗透性等指标，采用相关性分析，综合分析了不同植被类型的土壤水分和土壤温度的交互作用关系，阐明了不同植被类型土壤的水热耦合机制。本研究有助于深化对黄土高原自然植被恢复过程中的土壤水热耦合与蓄持水能力的交互调控机制的认识，为指导黄土高原植被建设和评价植被建设中的土壤“水库”的储存和调控能力提供科学依据。