拜泉县的泥沙连通性研究

Research on Sediment Connectivity in Baiquan County

摘要: 东北黑土地区的黑土地地况决定粮食的生产保障，对中国的粮食安全问题至关重要。在东北黑土区，关于泥沙连通性的研究仍处在起步阶段。以拜泉县为研究区域，结合拜泉县的高程DEM、归一化植被指数NDVI等数据，通过计算泥沙连通性指数(IC)的大小，得出1990年、1995年、2000年、2005年、2010年、2015年和2020年的泥沙连通性指数的时空分布特征，将其运用Sen趋势分析、M-K检验分析得到了1990~2020年拜泉县的IC趋势变化情况，并且将拜泉县不同高程、坡度分别与IC进行叠加分析。结果表明：拜泉县1990~2020年泥沙连通性指数均值整体上呈现减小趋势，其中，1990年、1995年、2000年、2005年、2010年、2015年、2020年IC泥沙连通性指数IC均值分别为−9.27、−10.45、−12.34、−12.50、−12.57、−12.53、−12.40，泥沙连通性强弱与泥沙连通性指数的大小呈正相关，进而拜泉县整体泥沙连通性呈减弱趋势；拜泉县1990~2020年IC趋势特征为：其西北、西南高程较低、坡度较低区域的IC趋势为减少，其东南和中间河流区域的IC趋势为增加，其余区域的IC趋势为不显著变化；拜泉县高程在210~270 m之间、坡度在1˚~4˚之间、植被覆盖少的区域的泥沙连通性指数值较大，泥沙连通性较强，这些区域往往更容易发生黑土侵蚀。

Abstract: The fertile black soil in Northeast China plays a pivotal role in ensuring the nation’s food security, making it a cornerstone of China’s agricultural stability. In the black soil region of Northeast China, research on sediment connectivity is still in its nascent stages. Taking Baiquan County as the research area, by integrating data such as the Digital Elevation Model (DEM) and the Normalized Difference Vegetation Index (NDVI) of Baiquan County and calculating the magnitude of the sediment connectivity index (IC), the spatio-temporal distribution characteristics of the sediment connectivity index from 1990, 1995, 2000, 2005, 2010, 2015 to 2020 were obtained. Subsequently, by applying Sen’s slope estimator and the Mann-Kendall test, the trend changes of the sediment connectivity index (IC) in Baiquan County from 1990 to 2020 were analyzed. Additionally, an overlay analysis was conducted to examine the relationship between the IC and different elevations and slopes in Baiquan County. The results show that the mean value of the sediment connectivity index in Baizhan County from 1990 to 2020 generally shows a decreasing trend. Among them, the mean values of the IC sediment connectivity index IC in 1990, 1995, 2000, 2005, 2010, 2015, and 2020 were −9.27, −10.45, −12.34, −12.50, −12.57, −12.53, and −12.40 respectively. The strength of sediment connectivity is positively correlated with the magnitude of the sediment connectivity index. Therefore, the overall sediment connectivity in Baizhan County shows a weakening trend. The IC trend characteristics of Baiquan County from 1990 to 2020 are as follows: In the areas in the northwest and southwest with lower elevations and lower slopes, the IC trend is decreasing; in the southeastern and central river areas, the IC trend is increasing; and in the remaining areas, the IC trend shows no significant change. In the areas of Baiquan County with elevations ranging from 210 to 270 meters, slopes ranging from 1˚ to 4˚, and less vegetation coverage, the sediment connectivity index values are larger and the sediment connectivity is stronger. These areas are often more prone to black soil erosion.