【摘要】 2011年第1次全国水利普查水土保持专项普查基于全国各省(区、市)土壤类型图和土种志剖面数据，制作首张全国土壤可蚀性因子分布图(简称2011版K值)。为了提高土壤侵蚀评价的准确性和可信度，2022年利用全国土系调查数据和随机森林制图方法对中国土壤可蚀性因子分布图进行更新(简称2022版K值)。以全国水蚀区2011版和2022版的土壤可蚀性因子(简称K值)为研究对象，分别在流域尺度和不同土壤类型下对K值大小及空间分布进行研究。结果表明：2022版全国平均K值(0.029 8 t·hm~2·h/(MJ·mm·hm~2))略低于2011版K值(0.032 3 t·hm~2·h/(MJ·mm·hm~2)),说明全国水土流失治理发展状况有向好的趋势。其中栗钙土、暗棕壤、盐碱土等土壤类型K值的降低幅度最大，潮土、褐土、黄壤等土壤类型的K值则有所升高。K值降低主要与退耕还林、土壤改良等政策措施的出台和布设有关，升高则与集约化耕作及坡地侵蚀有关。该结果可为水土流失动态监测及治理成效评价提供科学依据。更多还原

【Abstract】 [Background] The soil erodibility(K factor) is one of the key factors in calculating soil erosion modulus using the Chinese soil loss equation(CSLE). Therefore, obtaining an accurate distribution map of K factor is necessary for the national monitoring of soil and water loss in China. The current available Chinese K factor map was made during the soil and water conservation measures survey in the first national census in 2011, based on soil type maps of provinces(autonomous regions and municipalities) and soil profile data from the second national soil survey(K value in version 2011 for short). It is necessary to update the K value in the version 2011 and study the changing characteristics of K factor from the version 2011 to the version 2022(see below). [Methods] In order to increase the accuracy and reliability of soil erosion assessment, an updated K factor map was completed in 2022, using the random forest prediction method and soil profile data from the “Investigation of Chinese Soil Series”(K value in version 2022 for short). The K factor maps in the version 2011 and 2022 were chosen as the research projects, and their value size and spatial distribution in the major river basins and soil type of China were compared. [Results] 1) The mean value of the national K value in the version 2022(0.029 8 t·hm~2·h/(MJ·mm·hm~2)) was slightly lower than that in the version 2011(0.032 3 t·hm~2·h/(MJ·mm·hm~2)), indicating a positive trend in the development of soil erosion control in China. Except for the Haihe River Basin and Songliao River Basin, the K value in the version 2022 in each basin increased when compared to the K value in the version 2011. Among them, the K factor of castanozems, dark brown earths, saline soils and other soil type decreased the most, while the K factor of fluvo aquic soils, cinnamon soils, yellow earths and other types of soil increased. 2) The trend of changes in the national mean value of K factor was consistent with the dynamic trend of a decrease in the area and degree of soil erosion nationwide. The decrease in K factor was mainly related to reasons such as Returning Farmland to Forests and soil amendment, while the increase in K factor was related to intensive cultivation and slope erosion. [Conclusions] This study may provide a basis for dynamic monitoring of soil erosion and evaluation of the effectiveness of soil and water conservation management. In the future, it is necessary to strengthen ecological protection, improve soil quality and its ability to resist erosion.更多还原