近300年中国耕地数据集重建与耕地变化分析

Reconstruction and change analysis of cropland data of China in recent 300 years

针对中国历史时期不同政体耕地记录的特点,分别采用因素修正、引用替换、线性内插、衔接对比、人地关系检验、垦殖趋势检验、行政面积比例调整等方法对历史耕地数据进行修正,重建了基于现代省界的近300年中国分省耕地数据集,从数量角度对中国耕地总量和分省耕地变动特点进行分析,得到以下主要结论:①在耕地总量上,SAGE和周荣的数据明显高估,本文结果与HYDE、CHCD和章有义数据的平均差异率在15%以下;但在省域尺度上,与SAGE、HYDE数据库存在明显差异,相对差异率>30%的省份比重分别为94%和61%,与CHCD数据较为接近,相对差异率>30%的省份比重为22%,但部分省份差异明显,仍需进一步分析研究;②伴随清中期后的人口爆炸,近300年中国耕地增长近3.2倍,由清朝初年的42.4×106hm2增加至1985年的136.9×106hm2,根据增长速率变化可分为五个阶段,即清前中期快速增长阶段、清后期低速增长阶段、民国时期波动阶段、建国初期剧烈增长阶段和建国后耕地流失阶段,影响耕地变化主要是国家政策、战乱、经济发展等驱动因素。③从省域尺度看,近300年中国各区域耕地变化差异显著。清初,中国耕地主要集中于长江中下游平原、黄淮海平原、关中盆地及银川平原等地,此后,内地的垦殖活动不断增强,外围农区呈由南向北的趋势不断开荒。建国后,耕地开垦逐步向西北和东北方向发展。

Historical land-use and land-cover changes caused by human activities during thelast three centuries have been regarded as one of the five key frame issues in the LUCCproject. China, with a history of 5000 years, has had its population boom ever since the earlyQing Dynasty （around AD1700）, and unprecedented development of national agriculturalreclamation had started, left China as one of areas with rapid land-use and land-coverchanges. Currently, there are two global historical land use datasets, generally referred as the＇RF datasets＇ and ＇HYDE database＇, but at the zonal level, these global datasets are widelydoubted with coarse resolution and inevitable errors. Academics have tried to reconstructChina＇s historical land-use and land-cover both quantitatively and spatially, but there areremarkable differences in their results, thus bringing troubles to relevant researches. Since thequantity forms the backbone of cropland restructuring, this paper grounded itself on China＇shistorical records and related research achievements, and reconstructed China＇s provincialcropland data at the modem boundaries from 1661 to 1985, using a variety of methods basedon resources and population, such as factor revision, man-land relationship test, andreclamation trend examination, etc. Our results differ less from HYDE, CHCD and Zhangwith an average difference rate of less than 15%. But at the provincial level, our results arecloser to CHCD, with 22% of provinces＇ average difference rate being over 30%. Butsignificant diversities were found in a few provinces and further researches are needed. Thenwe analyzed China＇s cropland growth process and regional change characteristics. The resultsshow that ever since the population boom in the Qing Dynasty, China＇s cropland trebled from42.4x10^6 ha in the early Qing Dynasty to 136.9x10^6 ha in 1985. In terms of the growth rate,the process of China＇s cropland rise can be identified into five periods. Significant differencesexisted among the provincial cropland change. At the beginning of the Qing dynasty, China＇sfarming activities mainly existed in the Yangtze River Plain, the Huang-Huai-Hai Plain,Guanzhong Basin and Yinchuan Plain. Thereafter, reclamation activities expanded to outeragriculture areas. Since the founding of the People＇s Republic of China, Northeast China andNorthwest China have been major sources of additional cropland. National policy, disasters,wars, and economic development, are main factors affecting cropland changes.