延河流域典型治理阶段的土壤保持功能时空变化及驱动因素分析

Temporal and Spatial Variation of Soil Conservation Function and Its Driving Factors in Typical Reclamation Stage in Yanhe River Basin

[目的]探究黄土高原所进行的退耕还林(草)及治沟造地等典型治理工程的生态系统水土保持功能时空变化及其驱动因素,对于黄土高原进一步发展具有重要指导作用。[方法]通过构建延河流域InVEST生态服务功能模型和地理探测器的方法,在验证的基础上,研究了典型治理阶段流域的生态系统土壤保持功能。[结果](1)在时间变化上,与退耕还林前(1990-2000)相比,退耕还林期(2000-2010)和退耕还林+治沟造地期(2010-2017)的多年平均土壤保持量分别增加了32.29%,55.61%,年均增加4.92×10^(6)t;(2)在空间分布上,林草地和治沟造地的面积增加区域与土壤保持量增加区域具有一致性,治沟造地工程使得延河流域耕地整体的土壤保持能力提高,单位造地面积的土壤保持量增加7 t/hm^(2)。土壤保持量随坡度、高程的增加呈现先增加后减少的趋势,在海拔1200~1500 m,坡度15°~25°范围内土壤保持总量占年总土壤保持量比例较高。[结论]土地利用类型的变化是影响土壤保持空间分布格局的主要驱动因子。延河流域土壤保持功能时空变化的驱动因素分析为黄土高原生态服务功能改善提供了科学支撑。

[Objective]It is important to explore the temporal and spatial changes of soil conservation function and driving factors in the Loess Plateau under the typical management such as returning farmland to forest(grassland)and gully land consolidation project,so as to guide the further development of the Loess Plateau.[Methods]Soil conservation function in typical reclamation stage in this basin by constructing the InVEST ecosystem service function model and geographic detector method in Yanhe River Basin.[Results](1)In terms of time change,compared with the period before returning farmland to forest(1990-2000),the annual average soil conservation amount increased by 32.29%and 55.61%during the period of returning farmland to forest(2000-2010)and the period of returning farmland to forest+gully land consolidation project(2010-2017),respectively,with an annual average increase of 4.92×106 t.(2)In terms of spatial distribution,the increasing area of forest and grass lands and gully land was consistent with the increasing area of soil conservation,gully land consolidation project improved the overall soil conservation capacity of cultivated land in Yanhe River Basin,and the soil conservation capacity per unit land reclamation area increased by 7 t/hm^(2).The amount of soil conservation increased first and then decreased with the increase of slope and elevation,and the proportion of total amount of soil conservation to total amount of soil conservation was higher in the slope ranging from 15°to 25°at altitude ranging from 1200 m to 1500 m.[Conclusions]The change of land use type was the main driving factor affecting the spatial distribution pattern of soil conservation.The analysis of the driving factors of the temporal and spatial changes of soil conservation function in the Yanhe River Basin can provide scientific support for improvement of ecological services on the Loess Plateau.