鄂尔多斯高原明长城的地理界线意义

鄂尔多斯高原明长城位于明万里长城的中部，是明代边防体系的重要组成部分，明长城的地理位置是当时综合自然-社会-经济诸多因素的结果。在实地考察的基础上，从地貌、气候、农牧业界线三个方面分析了明长城的地理界线意义。明长城一线是鄂尔多斯高原与黄土高原的地貌界线，长城南北地貌类型、地貌特征差异显著。明长城处在中国夏季风的尾闾，是中国季风区与非季风区、暖温带与中温带、半湿润区与半干旱、干旱区的分界线。明代鄂尔多斯高原的长城是农牧业的分野，同时鄂尔多斯高原明长城位于中国农牧交错带中部的中轴位置，明长城两侧生产方式和土地利用显著不同，具有农牧分界线的地理意义。研究结果可加深对明长城价值的认识并促进长城的遗产保护。

Significance of the GreatWall of Ming Dynasty in Ordos Plateau as geographical boundary

Located at the middle of the Great Wall of the Ming Dynasty,the Great Wall of the Ming Dynasty in Ordos Plateau was an important component of frontier defense system in the Ming Dynasty. Therefore,the study of its scientific value is the basis for cognizing and protecting the Great Wall. Through a lot of field surveys of areas along the Great Wall of Ming Dynasty in Ordos Plateau,the paper proposed that as Ordos Plateau was short of geographic indications such as mountains and rivers,the Great Wall of Ming Dynasty became an important geographic indication after its formation. So,acting as a geographical boundary,it is of great significance in terms of geomorphology,climate,and agricultural and pastoral production.(1)The Great Wall of the Ming Dynasty is a geomorphological boundary between Ordos Plateau and Loess Plateau. The north side of the Great Wall of Ming Dynasty features high plains with highlands and lowlands as well as broad deserts,where wind action is the major exogenetic force; while the south side of the Great Wall of Ming Dynasty features the loess landform which consists of hills and gullies,where water erosion is frequent.(2)As the Great Wall of Ming Dynasty is located at the marginal area of summer monsoon in China,its south side is monsoon region,while its north side is non-monsoon region; in terms of temperature,its south side is in warm temperate zone,while its north side is in mid-temperate zone; and in terms of humidity,its south side is in semi-humid region,while in north side is in semi-arid or arid region. Therefore,the Great Wall of the Ming Dynasty is of geographical significance as a climatic boundary.(3)The Great Wall of the Ming Dynasty in Ordos Plateau is located at the central axis of the middle of China's agricultural and pastoral crisscross area. After the Great Wall of the Ming Dynasty was constructed, it became the boundary that divides China's agriculture and animal husbandry. Agricultural production models and land use in its two sides are obviously different. Its north side owns China's important pastoral areas and husbandry production zones,while its south side has been China's important dry-farming area since Qin and Han Dynasties. Therefore,the Great Wall of the Ming Dynasty is of geographical significance as an agricultural and pastoral boundary. The paper analyzed the significance of Great Wall of the Ming Dynasty in Ordos Plateau as geographical boundary from the perspective of regional differentiation. So,it is of practical significance in terms of discovering the scientific value of the Great Wall of the Ming Dynasty and facilitating heritage protection of the GreatWall.