Development of models to predict land-use-induced soil pore-space changes and their hydrological impacts

随着对农产品需求的增加和极端天气条件的发生，水土资源更受公众关注。因此，适当的土地利用作为水土保持的预防因素变得越来越重要。适应战略的规划往往基于数值模型的应用。利用这些模型，可以估计和评估在现代和变化的气候条件下假设的土地利用变化对植物生长和水分平衡成分的影响。作为现有模型的前提条件，土壤水力特性在时间上是恒定的。然而，以往的研究表明，由于土地利用，土壤结构及其土壤保水和导水功能发生了显著变化。如果忽略土体结构的动力特性，模型结果的不确定性增加。这可能会导致不正确的规划和更消耗资源的土地使用。因此，这项研究的目标是a)测量土地利用引起的土壤结构和土壤水力性质的变化，以及b)将结果应用到使用数学方程量化变化的水文模型中。这些方程描述了基于不同土地利用方式(例如，土壤耕作、作物轮作、植树造林)土壤孔隙大小分布演变的土壤持水和导水率的时间变化。为了得出土地利用对与水文相关的土壤性质的影响的一般原则，我们将分析从勃兰登堡到斯特里亚的气候样带上类似土壤的可比土地利用实践。对于土壤水力特性的表征，将采用野外方法(防护罩渗透仪和染料示踪剂实验)和实验室方法(瞬时蒸发实验)相结合。这种方法可以更好地区分大孔域和基质流域，这可能是描述土地利用引起的土壤孔隙空间变化的功能的基础。我们预计，不同的土地利用措施将对大孔隙产生更大的影响。这项研究将增加我们对不同土地利用方式下土壤孔隙空间变化的认识。在更好地了解相关过程的基础上，我们将开发能够量化适应性土地利用对土壤水力性质、对水循环组成部分(土壤水容量、地下水补给、水质)以及对生物质生产的影响的方法和模型。这将是制定和评估可持续土地利用制度的基础。

As the demand for agricultural products and the occurrence of extreme weather conditions increase, the resources soil and water are more attracted by the public. Therefore, an adaptive land use as a preventative element for soil and water conservation gains in importance. Planning of adaptation strategies are often based on the application of numerical models. With these models, the impact of hypothetical changes in land useunder recent and changing climatic conditions on plant growth and water balance components can be estimated and evaluated. As a pre-requisite in existing models, soil hydraulic properties are seen to be temporally constant. However, previous studies have shown that soil structure and with it the soil water retention and hydraulic conductivity functions change significantly as a result of land use. If the dynamics of soil structure are neglected, the uncertainty of the model results increases. This could lead to incorrectplanning and a more resources-consuming land use. Therefore, the objectives of this study are a) to measure landuse-induced changes in soil structure and in the soil hydraulic properties and b) the implementation of the results into hydrological models that quantify the changes using mathematical equations. These equations describe temporal changes of soil water retention and hydraulic conductivity based on the evolution in the soilpore-size distribution for different land use pratices (e.g., soil tillage, crop rotation, afforestation). To derive general principles for the influence of land use on hydrologically relevant soil properties, we will analyze comparable land use practices with similar soils along a climatic transect from Brandenburg to Styria. For the characterization of the soil hydraulic properties, field methods (hood infiltrometer and dye tracer experiments) will be combined with laboratory methods (transient evaporation experiments). This approach allows a better differentiation between macropore and matrix flow domains, which may be fundamental for the development of functions describing land use-induced changes of the soil pore space. We expect that the different land use measures will have a stronger influence on the macropores. The study will increase our knowledge about soil pore space changes under different land use pratices. Basing on a better understanding of the involved processes we will develop methods and models that are able to quantify the impact of an adaptive land use on the soil hydraulic properties, on components of the water cycle (soil water capacity, groundwater recharge, water quality), and on the production of biomass. This will be the basis for the development and assessment ofsustainable land use systems.