全国第二次土地调查前后中国耕地面积变化的空间格局

长期以来中国耕地数量受到国内外的高度关注,但是中国的耕地面积到底是多少,一直是个谜,特别是在耕地面积出现几十年持续下降的背景下,全国第二次土地调查结果居然比调查前多出了2亿多亩。论文利用全国第二次土地调查前后的耕地面积数据,从耕地总面积和不同类型的耕地面积两个维度,在不同空间尺度上,对耕地面积数据进行对比分析。研究表明：1）从区域尺度来看,“二调”多出的2亿多亩耕地主要分布在东北、华北与西北地区,其中东北地区几近一半,华南是唯一减少的区域;从省级尺度来看,26个省份耕地面积增加,以东北三省和新疆、内蒙古居多,京沪苏粤陕出现减少,尤以苏粤为甚;从市级和县级尺度来看,耕地增减空间集聚明显,耕地增加的地市和县市均以东北最为集中,耕地减少的地市以珠三角和长三角最为集中,耕地减少的县级单元以粤苏云三省最为集中。2）耕地的三种类型都出现增加,但旱地最多（53%）、水田最少（10%）;水田和水浇地均“北增南减”;旱地的增减主要分布在北方,且增减的空间分布都非常集中,东北增加较多,黄淮海平原减少较多。耕地分布重心的持续北移,加剧了水土资源的不协调性,从而影响耕地的质量,未来中国政府在高度关注耕地数量变化的同时,更应强化耕地质量的提高与保护。

Spatial Pattern Change of the Cultivated Land before and after the Second National Land Survey in China

The quantity of the cultivated land is related to the food security and the basic national conditions of China as well as many macro decisions, and thus it has received great concerns from home and abroad. The Chinese government attaches great importance to the protection of cultivated land, makes it as a basic national policy, and sets up a Cultivated Land Protection Red Line of 0.12 billion hectare (1.8 billion mu). However, the area of the China’s cultivated land remains a mystery, especially when the Second National Land Survey released in 2013 disclosed an increase of more than 13.33 million hectare (0.2 billion mu) under the background that the area of cultivated land has been declining for decades. In this paper, we carry out comparative analysis on the data of the cultivated land area before and after the Second National Land Survey at different spatial scales from the dimensions of the total area of the cultivated land and the area of different types of cultivated land. The results show that: 1) At the regional scale, the increased 13.33 million hectares (0.2 billion mu) of cultivated land in the Second National Land Survey mainly distribute in the Northeast China, the North China, and the Northwest China, that nearly half of the increase are in the Northeast region. The South China is the only region with cultivated land area reduction. At the provincial scale, the cultivated land area increased in 26 provinces, especially in the three provinces in Northeast China, Xinjiang and the Inner Mongolia. Beijing, Shanghai, Jiangsu, Guangdong and Shaanxi had decline of cultivated land area, especially Guangdong and Jiangsu. At the municipal scale, the spatial agglomeration of cultivated land increase is significant. The cities with increase of cultivated land concentrate in the Northeast China, and the cities with reduction of cultivated land concentrate in the Pearl River Delta and the Yangtze River Delta. At the county scale, the spatial agglomeration of cultivated land is obvious. Counties units with cultivated land increase are centralized in the Northeast China, and the counties with reduction of cultivated land concentrate in provinces of Guangdong, Jiangsu and Yunnan. 2) Three types of cultivated land have increased. The dry land increased the most (53%), and the paddy field increased the least (10%). The paddy field and the irrigated land are increasing in the North and decreasing in the South, and the number provinces with increased land and decrease land are almost the same. Both the increase and the decrease of the dry land mainly distributed in the North. The spatial distribution of changes is very concentrate, that most increase occurred in the northeast and most decrease appeared in the Huang-Huai-Hai Plain. The center of the cultivated land continues to move northward, which exacerbate the spatial incoordination of water and soil resources and thus do harm to the quality of the cultivated land. In the future, the Chinese government should pay close attention to not only the quantity of cultivated land change, but also the improvement and protection of the quality of the cultivated land. The increased area of the cultivated land in the Second National Land Survey resulted from a variety of reasons. The main reason is that the technology and methods adopted in the Second National Land Survey disclosed the concealed area in the false report of the local government.