Research On The Changes Of Cultivated Land Area In Chaohu Lake Basin Since The Mid-Holocen

The reconstruction of historical arable land area provides basic information for the study of agricultural development history and provides key basic data for quantitative assessment of the impact of arable land reclamation on the ecological environment.The Chaohu Lake basin has a long history of human activities,with a splendid Neolithic culture developed in the middle Holocene,and has gradually developed into a representative traditional agricultural area in the lower reaches of the Yangtze River since the historical period.The study of arable land area changes in the Chaohu basin since the middle Holocene is important for revealing the evolution of the natural environment and the history of human activities in the lower reaches of the Yangtze River,and can provide support for regional ecological environmental protection and sustainable development.This paper uses archaeological data,population and field assignment data from historical documents,as well as archival and statistical data and remote sensing data to compile information and select methods for estimating cultivated land area in nine stages,namely,the Middle and Late Neolithic,Shang and Zhou periods,Han,Tang,Song,Ming,Qing,Republican,and contemporary times,to estimate the cultivated land area in the Chaohu Lake basin since the Holocene.Combined with ancient maps and other information,the area of lakes in historical periods was estimated,and the total reclaimable area of the Chaohu basin was calculated more precisely.Finally,a long time series analysis of the change in cultivated area was conducted,and the ecological and environmental impacts of regional cultivated land reclamation were discussed in conjunction with relevant records from regional literature and previous studies.The main research contents and results are as follows:(1)The method of using archaeological data,recorded population,and farmland data to revise or estimate cultivated land data has been used to obtain information on the middle and late Neolithic period,Shang and Zhou dynasties,Yuanshi 2 years(2 years),Yonghe 5 years(140 years),Tianbao 11 years(752 years),Yuanfeng 1 years(1078 years),Chongning 1 years(1102 years),Hongwu 26 years(1393 years),Hongzhi 15 years(1502 years),Wanli 10 years(1582 years),Chongzhen 17 years(1644 years)The cultivated land area of 21 time sections including the 21st year of Kangxi(1682),the 13th year of Yongzheng(1735),the 25th year of Jiaqing(1820),the 5th year of the Republic of China(1916),the 8th year of the Republic of China(1919),the 21st year of the Republic of China(1932),the 28th year of the Republic of China(1939),1953,1980’s,and 2020.The estimated results are as follows:(1)The cultivated area in the Middle and Late Neolithic period(6.0～4.0 ka BP)is at 132.49km~2,and the cultivated area in the Shang and Zhou period(3.6～2.8 ka BP)has decreased compared with the Middle and Late Neolithic period,at 112.24km~2;(2)The cultivated area in the Han Dynasty has increased more than before,and the cultivated area in the Han Dynasty itself has fluctuated,with the cultivated area in 2 A.D.-140 A.D.at 1974.71 km~2-1369.63 km~2;(3)since the Tang and Song dynasties,the arable area of Chaohu basin has a great change,the arable area in 752 years of the Tang dynasty was 2697.23 km~2,1078 years of the Song dynasty,the arable area increased more than the Tang dynasty,increased to 4581.40 km~2,nearly double the 752 years of the Tang dynasty;(4)after the Ming dynasty,the arable area grew faster,to1582 reached the highest The arable land area was 7729.01km~2in the early Qing dynasty,the arable land area declined rapidly to 3403.82km~2in 1644;(5)The arable land area did not change much in the Republic of China,of which the arable land area was relatively large in1932,reaching 7670.05km~2;(6)The contemporary arable land area was 7208.17km~2in 1953,and by 2020 the arable land area was The spatial distribution of arable land has been the main reclamation area in Hefei County since the Ming Dynasty,while the reclamation rate of arable land in the mountainous areas of Shucheng and Hanyama Counties is low.(2)The lake area of Chaohu Lake has changed considerably throughout history.Based on the shoreline mapping,the lake area of Chaohu Lake can be estimated,and the reclaimable area of Chaohu Lake basin can be accurately calculated,which improves the data accuracy of the cultivation rate.(3)The cultivated land reclamation rate as a whole becomes more intense as time gets closer to the present,with the reclamation rate in the middle and late Neolithic period being only 1.08%,increasing in the Han Dynasty,reaching 16.61%in the Tang Dynasty,increasing to 26.71%in 1078 in the Song Dynasty,reaching 47.67%in 1582 in the Ming Dynasty,and stabilizing at about 27.93%-46.90%in the Republic of China,and in 1953 The cultivated land area reclamation rate was 45.00%,and since 2000 the cultivated land reclamation rate has increased to 67.90%.(4)The study of the impact of cultivated land reclamation on the ecological environment of Chaohu Lake basin shows that agricultural reclamation has a greater impact on the ecological environment in terms of lake shrinkage,soil erosion,and drought disasters.