Reconstruction Of Cultivated Land Spatial Pattern From Pre-Qin To Han Dynasty In North China

Land use and land cover change(LUCC)is an important driving force for regional and global climate and environmental change.Since Holocene agricultural origin of global human activity is increasing,and the late neolithic(in China is about 7~5 ka)from slash-and-burn agriculture development is in the transition stage of LeiSi tillage,took in the extensive primitive agriculture to the transition of intensive cultivation agriculture beginning,is the human in han dynasty into the iron age after finalize the design phase of development of traditional agriculture.Therefore,the above period is considered as the key period for human activities to change the natural vegetation.The long-term reconstruction research of LUCC has great scientific and application value in predicting future climate change,making policies,avoiding risks and human adaptation.Abundant archaeological remains and historical documents in north China recorded the human activities in the above periods.Based on the archaeological data discovered and excavated,this paper used the archaeological correlation modeling method to calculate the population size and arable land area of north China in the late neolithic period and the xia dynasty.By collecting and sorting out relevant historical documents,the spatial distribution pattern of cultivated land in north China during the above period and the han dynasty was reconstructed on the basis of previous studies.Concluded as follow:(1)The population size of the late Neolithic Age,Xia Dynasty and Han Dynasty in North China is about 131.52×10~4people,100.57×10~4people,3218.13×10~4people;their cultivated land area is about:2.66×10~4 km~2,2.03×10~4 km~2,20.02×10~4 km~2;the entire cultivated land in the late Neolithic period,Xia Dynasty and Han Dynasty in North China accounted for 11.96%of modern cultivated land respectively.9.13%,90%;the reclamation rates in the late Neolithic period,Xia Dynasty,and Han Dynasty in northern China reached 5.18%,3.95%,and 38.96%,respectively.(2)From the late period of the new era to the Han Dynasty,the population and cultivated land area in North China experienced a process of first reduction and then increase.During the period from the late Neolithic to the summer of 1000 years,the population decreased by about30.95×10~4people,and the cultivated land decreased by 0.63×10~4km~2.After the development of the Xia Dynasty to the Western Han Dynasty in the past 2000 years,its population increased by about 3027.56×10~4 people,and the number of cultivated land increased by about 17.99×10~4 km~2.(3)In the topographic distribution:from the late Neolithic period to the Han Dynasty,the cultivated land in the plain area below 200 m above sea level accounted for 75.05%,75.94%,and 89.38%,respectively;the hilly areas with an altitude of 200 m~500 m accounted for 19.02%and 15.35 respectively.%,8.38%;the areas with an altitude of 500 m~1000 m accounted for5.18%,7.32%,and 2.07%,respectively;the high-altitude areas above 1000 m accounted for only0.75%,1.39%,and 0.17%,respectively.From the slope point of view,the arable land grid in the late Neolithic period is mainly distributed in the flat arable land below 2°,accounting for 92.04%of the cultivated land grid,and the number of grids of the sloping farmland(2~6°)and the sloping land(6°or more).They accounted for only 7.87%and 0.09%respectively.In the Xia Dynasty,the number of grids distributed below 2°accounted for 90.75,and the grid number of gentle slope farmland and slope farmland accounted for 8.25%and 1.00%respectively.In West Han Dynasty,there were 94.86%of cultivated land.The grid distribution is below 2°,and the gentle slope farmland and slope farmland account for only 4.86%and 0.28%,respectively.(4)From the perspective of the overall spatial and temporal pattern of cultivated land distribution,from the late Neolithic period to the Han Dynasty,the probability of the distribution of cultivated land decreased continuously,and the cultivated land was distributed from block to concentrated.Among them,from the late Neolithic period to the Xia Dynasty,the cultivated land was collected from the Luoyang Basin,the Weihe River,the Luohe River and the Yihe River Valley in the central and western Henan,to the southeastern Henan Valley and the well-drained mountainous areas of the Luoyang Basin,from the hills around the Central South Mountain in Shandong.The piedmont alluvial plains are concentrated in the northern and western parts of Luzhong Mountain,from the Taihang Mountains in the west of Hebei Province and the south and north of the Yanshan Mountains to the south of Fujian and the northeastern Yunnan.In general,the cultivated land in Henan is concentrated to the southeast of Henan,the cultivated land in Shandong is concentrated to the west and north,and the cultivated land in Hebei is moving southward.From the Xia Dynasty to the Han Dynasty,it experienced tremendous productivity and social changes.Its cultivated land was concentrated in the plains,and the areas of the Neolithic Age and the distribution of cultivated land in the Xia Dynasty were basically distributed in the Han Dynasty.Changes in the temporal and spatial patterns of cultivated land indicate that humans'ability to transform nature is increasing and their strength is increasing.The scope of human activities is expanding,and the pressure on the ecological environment is increasing.Human beings have already had a profound impact on the natural environment through agricultural production activities,especially in areas such as North China where development is early and agriculture has been continuously developed.In the early days of human history,Human activities are already a force that cannot be ignored in driving changes in the landscape.Therefore,in the current development,we must pay more attention to the relationship between environmental carrying capacity and population,and develop moderately.