基于地表过程的区域土壤养分时空变化模拟

It is necessary to detect the spatial-temporal variation of soil properties accurately at regional scale for its effect on quality and safety of agri-food, the human health and the sustainable development of society and economy. The best way to predict soil properties is to relate the spatial-temporal variation of soil properties with the surface elments from the view of land surface process. However, it is difficult to express above relationships accurately because of the complexity of the land surface system. To predict spatial-temporal variation of soil properties accurately, several issues must be carefully took into account: which are the key surface factors for a specific region, how to depict the qualitative and quantitative surface factors and their scale effects, and which is the best way to capture the nonlinear relationships between soil properties and surface factors. Aiming at above problems, this study is to establish a method to predict the spatial-temporal variation of soil nutrient at regional scale with the view of land surface process. This model will be validated with the soild variation during the past 30 years in Renshou County, a typical hilly area in central Sichuan basin.

区域土壤时空变化已是系及社会经济发展的迫切实际和科学问题。目前，准确模拟土壤时空变化最有潜力的途径，是在空间信息技术支持下，从地表过程角度确立地表相关因子变化与土壤时空变化的相互作用关系。..但是，要实现该目标系列问题尚待深入分析与探讨：区域地表因子的合理选择与表达、地表因子的尺度效应、地表系统的非线性等。因此，本项目将针对上述关键问题，根据区域土壤养分要素时空分布特征及相关地表因子的驱动机制，建立基于地表过程的区域土壤养分时空变化模拟方法；并在县域尺度上，以自然和人为过程较为复杂的川中丘陵近30年土壤养分变化为对象，验证和完善所研究的模拟方法，以期能满足复杂地表背景区域土壤性质时空变化的研究和实际需求。

针对区域土壤养分时空变化高精度模拟问题，本项目分析了区域尺度土壤养分时空变化的地表因素，提出了融合定性及定量地表因素的模拟方法，该方法以土壤概念模型为基础，建立了区域土壤养分时空变化模拟方法，该方法充分考虑了不同地表因素对区域土壤养分空间异质性形成的作用及解释能力、养分与地表因子间关系的非线性、空间非平稳性以及各因子间共线性。以国家尺度和川中丘陵县域为案例区，进行了区域土壤养分时空变化模拟，为区域土壤养分时空变化高精度模拟模型的构建可供了可信的理论基础和可行的参考方案。