Demographic Changes, The Relationship Between Land Use And Environmental Change Study

With the demand of globe ecological environmental problems increasingly serious, the natural changes of human living environment and the evolutions of environment changes under human activities were more and more paid attention to. The research of Land Use/Land Change (LUCC) ,as one of the core topics about the study of global environmental changes, is also an multidisciplinary topic popularly. China loess plateau had the longest time and most complete paleo-climate record, simultaneous it's the residential land surface in past and present. The regional environment changes became extremely strenuous since 10,000 years. The fact shows that human activities are the main cause of the environment changes of loess plateau. Which contributions human activities act on the environment changes in historical times? How to expressed these contributions? How to alleviate them? Focuses of these problems are our research directions.The research objective is the relationship between population change and land use, and environmental change. This thesis has made full use of the historical geography, the geomorphology, the demography, selected classical areas of the loess plateau and analyzed important humane and natural events from the Qing dynasty to the Minguo period. Simultaneous the paper extracted historical information to study the quantitative expression of population data and land data. Finally this thesis searched for the relationship between land use and environmental changes.This thesis analyzed land use changes of the typical landforms (loess plateau gully region, loess gulled-hilly area, loess hilly and gully region, wind sand grass shoal area and typical basin) and studied humanistic factors (policies, habitation transformation, tillage management, living habits) . The study considered that historic soil erosion in loess plateau gully region is the combined effects of natural erosion and man-made accelerated erosion. Man-made accelerated erosion is not decreased in war disasters and natural calamities. Simultaneous the paper thought that population pressure, production pattern and cultivation region are the main aspects of land use changes in loess plateau gully region, loess gulled-hilly area, loess hilly and gully region. Soil erosion became more and more serious with the steeper cultivation positions from slope land to beam top. In addition, by the analysis of population scale, population density and land utilizing scale, the study thought that the population scale showed decreasing tendency from loess plateau gully region, loess hilly and gully region to wind sand grass shoal area and population density showed semi-sector decreasing tendency Jiazhou and Suidezhou-centered. Land utilizing scale had positive correlation with population scale and land use intensity had positive correlation with population density. Soil erosion had positive correlation with population changes in time domain and natural erosion and man-made accelerated erosion had double effects on soil erosion in space.To sum up, the seasonal changes and regional changes of natural factors in northern of shaanxi loess plateau were significantly for regional climate. In the land utilization procedure, the problem of soil erosion was very outstanding. The degree of environmental destruction was not remarkable before The Republic of China period.