北宋后期黄河上游地区耕地格局重建——以河湟谷地为例

黄河上游的河湟谷地是人类活动历史悠久的地区之一,是黄河沿线耕地开垦的最西端,聚落和耕地重建对黄河流域人类活动和全球变化研究具有重要的现实意义。通过梳理大量历史文献资料,建立了北宋后期（1117年）河湟谷地聚落和耕地数据库,以聚落空间分布为基础,运用网格化模型,重建了北宋后期河湟谷地耕地格局。结果表明：（1）北宋后期河湟谷地聚落集中分布在黄河、湟水河干流沿岸海拔相对较低、坡度较缓的河流冲积和洪积平原。（2）河湟谷地的耕地总面积为304.67 km²,分配有耕地的网格仅占全区的16.16%,垦殖率最高的网格仅为24.16%,其中,湟水河谷耕地分布网格约占全部的74.06%,黄河干流约占25.94%,说明北宋后期耕地开垦主要集中在湟水河流域。（3）从聚落分布的海拔高度来看,大部分耕地网格分布在海拔2600 m以下的川水地区,说明当时耕地分布范围不大,海拔高度极大地限制了耕地的分布,耕地主要分布在灌溉条件相对优越的地区。（4）基于聚落重建耕地空间格局,其结果符合耕地随聚落分布的事实,更具有可靠性。

Reconstruction of cultivated land pattern in the upper reaches of the Yellow River in the late Northern Song Dynasty:Take Hehuang Valley as an example

The Hehuang Valley in the upper reaches of the Yellow River is one of the areas with a long history of human activities,and it is the westernmost part of cultivated land reclamation along the Yellow River.The reconstruction of settlements and cultivated land has practical significance for the study of human activities and global change in this basin.In this paper,a database of settlements and cultivated land in the Hehuang Valley in the late Northern Song Dynasty(1117)was established by combing a large number of historical documents.Based on the spatial distribution of settlements,the grid model was used to reconstruct the cultivated land pattern of the study area with an accuracy of 1 km×1 km.The results show that:(1)The settlements in the Hehuang Valley in the upper reaches of the Yellow River in the late Northern Song Dynasty are concentrated in alluvial and proluvial plains along the main stream of the Yellow River and Huangshui River with relatively low altitude and gentle slope,and the"City"is mainly distributed in the mountain pass in the relatively low altitude area,highlighting its defense function;"States and Castles"are mostly distributed along rivers with relatively flat terrain and relatively geo-safe;however,"Villages"are scattered along the tributaries of rivers,showing the characteristics of disorderly development.(2)The total cultivated land area in the Hehuang Valley is estimated to be about 304.67 km~2,with only 16.16%of the grids distributed with cultivated land and only 24.16%of the grids with the highest reclamation rate,among which 74.06%are distributed in the Huangshui Valley and 25.94%along the main stream of the Yellow River,indicating that cultivated land reclamation in the late Northern Song Dynasty is mainly concentrated in the Huangshui River Basin.(3)From the altitude of settlement distribution,78.09%of the cultivated land grids are distributed in the area of flat terrain with water below 2600 m above sea level,and 21.91%of the grids are distributed in the shallow mountains between 2600 m and 3200 m,indicating that the cultivated land range was not large at that time,and the altitude greatly restricted the expansion of cultivated land,which was mainly distributed in areas with superior irrigation conditions.(4)Rebuilding the spatial pattern of cultivated land based on settlement accords with the fact that cultivated land is distributed with settlements,which is more reliable.