风蚀对锡林郭勒草原土壤有机碳流失的影响研究

Soil particles can be released into the atmosphere in the form of dust under the effect of wind erosion, which will lead to the redistribution of soil organic carbon (SOC) through transport and deposition and therefore affect the global carbon cycling and global climate change directly. Due to rare studies on carbon cycling nowadays focus on impacts of wind erosion on the carbon cycling, the impact of wind erosion on SOC dynamics are still under debate. As a case study of temperate grasslands in China, this study employed quantitative analysis of SOC loss under the effect of wind erosion in the Grassland of Xilinguole, applying the multi-method of manipulative experiments, remote sensing monitoring and model simulations. Relationships between the quantity of soil wind erosion and the main impacting factors of wind erosion will be explored using the manipulative experiments for different types of grasslands under different levels of wind speeds. The spatial distribution of SOC content (%) will be estimated by the SOC empirical estimation model which will be developed by the relationship between the soil spectrum from remote sensing image and observation data of SOC. Parameters of the process-based wind erosion model will be corrected using the dataset of manipulative experiments for wind erosion. The spatial patterns of the quantity of soil wind erosion can be calculated by the process-based wind erosion model at regional scale using meteorological dataset, remote sensing images, inventory datasets, et al. The quantity of SOC loss under the effect of wind erosion can be got based on the coupling of soil wind erosion amount and the spatial distribution of SOC content. This study is expected to understand the effect of wind erosion on soil degradation and carbon cycling, providing the foundation of theories, methods, and technologies for the ecological restoration, ecological planning, and regional sustainable development in wind erosion regions.

风蚀造成大量地表土以沙尘形式释放至大气，通过运移与沉积对地表土壤有机碳重新分配，直接影响全球碳循环与气候变化。但目前研究极少顾及风蚀对碳循环的影响，急需开展风蚀对土壤有机碳动态的影响研究。本项目拟开展风蚀对我国北方草原（以锡林郭勒草原为例）土壤有机碳流失的影响研究。以“控制实验-遥感估算-模型模拟”为总体研究思路，通过风蚀控制实验研究不同风速水平下不同草原类型土壤风蚀量与其主要影响因子间的关系；基于遥感与样带调查数据，建立地表土壤有机碳含量（百分比）估算经验模型，反演土壤有机碳含量空间分布；利用控制实验数据校验风蚀模型，基于气象、遥感、清查等数据估算土壤风蚀量，结合土壤有机碳含量空间分布，估算风蚀影响下土壤有机碳流失量空间格局，研究风蚀对土壤有机碳流失的影响。本项目可为深入了解风蚀对土壤退化与碳循环的影响提供依据，对指导风蚀区生态修复、生态规划与区域可持续发展具有重要的理论意义与应用前景。

风蚀造成大量地表土以沙尘形式释放至大气，并通过运移与沉积对地表土壤有机碳及养分重新分配，可直接影响生物地球化学循环与气候变化。本项目开展了风蚀对我国北方土壤有机碳流失的影响研究，在完成原设定研究内容的基础上进行了进一步的扩展研究，包括模拟风蚀控制实验的样带调查、基于样带调查数据的风蚀模型参数校验、沙尘排放时空过程模拟及风蚀作用下我国北方土壤有机碳、氮、磷流失的估算。项目主要研究进展如下：①在我国北方进行了模拟风蚀控制实验的样带调查，涉及农田、典型草原、荒漠草原、灌丛荒漠、戈壁荒漠、沙漠等多种植被类型，行程6万余公里，采集了近300个样点的模拟风蚀数据；②基于风蚀样带调查及实验室分析数据，研究了土壤风蚀量与风速、植被类型、植被盖度、土地利用、土壤类型等因子间的关系，对风蚀起沙机理模型进行了评估与参数校验，参数调整后可较好的模拟中国北方沙尘排放情况，开发了风蚀模型起沙量计算模块；③在GIS平台下集成校准后的风蚀起沙机理模型，构建了沙尘排放时空模拟软件系统，在高时空分辨率气象数据的驱动下模拟了近30年 (1982-2011) 风蚀作用下我国北方干旱半干旱区沙尘排放的时空过程；④将校验后的风蚀起沙机理模型与空气质量模式(WRF-Chem)有机耦合，模拟了1980-2015年以来东亚地区(中国与蒙古国)高时空分辨率(1小时；36 km)的沙尘排放时空过程，并结合观测数据对模拟结果进行了精度评估，同时分析了近40年来沙尘排放与气温、降水、风速等气象因子间的关系；⑤基于沙尘排放模拟结果，结合土壤有机碳、土壤全氮以及土壤全磷含量的空间分布数据，计算分析了近几十年来我国北方风蚀作用下土壤碳、氮、磷流失的时空变化特征。本项目的开展为深入了解风蚀作用下我国北方沙尘排放的时空变化特征及其与气候变化的关系，以及风蚀对我国北方土壤有机碳、氮、磷流失的影响提供了科学数据支撑，对指导干旱半干旱区生态修复、生态规划与区域可持续发展具有重要的理论意义与应用前景。

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