三峡水库消落区人类耕种行为对水质的影响机制研究

The repeatedly prohibited tillage behavior in the Water-Level-Fluctuating Zone of Three Gorges Reservoir with its disordered, scattered features, is one of the major factors in the eutrophication and pollution of Three Gorges Reservoir water quality. However, the Influence process and extent remains unknown. Understand the influence mechanism of tillage behavior on water quality in the Water-Level-Fluctuating Zone of Three Gorges Reservoir, is of great importance to the ecological security in the Three Gorges Reservoir. .This study focus on the tillage behavior and water quality in the Water-Level-Fluctuating Zone of Three Gorges Reservoir. Based on farmer household survey, field spectral measurement, water sampling experiment and aerospace hyperspectral remote sensing, the patterns, types and spatial distribution of tillage behavior will be analyzed, the temporal and spatial dynamics of water quality key parameters will be retrieved and the quantitative effects of tillage behavior on water quality in critical stages of Water-Level-Fluctuating will be carried out. By quantitative analyze the characteristics of tillage behavior, reveal the influence mechanism of different types of tillage behavior on water quality, this study aims to provide data support for eco-compensation, scientific basis for agricultural non-point source pollution control and protection of Three Gorges Reservoir.

三峡水库消落区无序、分散的人类耕种行为屡禁不止，对消落区乃至三峡水库的水质产生了较大影响，然而其影响过程与程度尚未见相关研究。开展消落区人类耕种行为及其对水质的影响机制研究，对于维护三峡水库生态安全具有重要意义。本项目以消落区人类耕种行为与消落区水质为研究对象，通过开展农户调查、野外光谱测量、水体采样实验以及航空高光谱遥感实验，分析区域人类耕种行为的特征、模式、类型与时空分布，反演消落区水质关键参数的时空变化特征与规律，提取分析消落区水质本底参数特征，结合消落区干湿交错过程中关键时间节点开展人类耕种行为对水质的定量影响研究，探明消落区人类耕种行为的定量特征，揭示人类耕种行为对消落区水质的影响机制，以为区域生态补偿提供数据支撑，为消落区农业面源污染控制、三峡水库保护与管理提供科学依据。

为探究不同时空尺度土地利用与水质的相互关系，以澎溪河流域为研究对象，基于2019年和2020年的河流水质与土地利用数据，提取3种空间尺度(1000 m河段缓冲区、500 m河岸带缓冲区、子流域) 的土地利用类型，结合2个季节河流水质指标，采用冗余分析方法定量探讨土地利用对河流水质的多时空尺度影响，获得水质资源管理最有效的时空尺度．结果表明：1）在三种空间尺度下，旱地和水田的面积占比最大；2）水质指标存在时空差异性，多数水质指标均表现出在澎溪河主干高于其余三条支流的规律，以及在旱季的值高于雨季；3）土地利用在雨季和缓冲区尺度对水质影响更加显著，且灌木林对水质的解释程度最高，介于20.9%—46%之间。该研究结果为合理规划三峡库区土地资源提供了参考，同时为三峡水库的农业面源污染控制、生态保护与管理提供了科学依据。