1. State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
2. Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China
3. University of Chinese Academy of Sciences, Beijing 100049, China
4. Institute of Agricultural Resources and Regional Planning of CAAS, Beijing 100081, China
National Natural Science Foundation of China, No.41421001, No.41590845, No.41471388;
National Key Basic Research Program, No.2015CB954101;
Landform is an important factor determining the spatial pattern of cropland through allocating surface water and heat. Therefore, it is of great significance to study the change of cropland distribution from the perspective of geomorphologic division. Based on China's multi-year land cover data (1990, 1995, 2000, 2005, 2010 and 2015) and geomorphologic regionalization data, we analyzed the change of cropland area and its distribution pattern in six geomorphologic regions of China over the period 1990-2015 with the aid of GIS techniques. Our results showed that the total cropland area increased from 177.1 to 178.5 million hectares with an average increase rate of 0.03%. Cropland acreage decreased in southern China and increased in northern China. Region I (eastern hilly plains) had the highest cropland increase rate, while the dynamic degree of Region IV (northwestern middle and high mountains, basins and plateaus) was significantly higher than that of other regions. The barycenter of China's land cultivation had shifted from North China to northwest over the 25 years. Regions IV and I were the two high-growth regions of cultivated land. Region II (southeastern low-middle mountains) and Region V (southwestern middle and low mountains, plateaus and basins) were the main decreasing regions of cultivated land. The area of cultivated land remained almost unchanged in Region III (north China and Inner Mongolia eastern-central mountains and plateaus) and Region VI (Tibetan Plateau). The loss of cropland occurred mostly in regions I and II as a result of growing industrialization and urbanization, while the increase of cropland occurred mainly in Region IV because of reclamation of grasslands and other wastelands.
土地利用覆被变化（land use and land cover changes, LUCC）是环境变化的基本组成部分,对于维持生态系统的结构和生产力具有重要意义。土地覆被的变化影响着陆地表层物质循环和生命过程,如水循环、温室气体排放、资源可持续利用和生物多样性等,这些变化需要进一步分析时间和空间尺度的影响及效应[2,3,4]。同时,土地利用覆被变化也受全球经济、国家政策、气候变化等多种因素影响。从1995年开始,国际地圈生物圈计划（IGBP）和全球变化人文因素计划（IHDP）制定并开始实行土地利用/土地覆盖变化科学研究计划,将其作为全球变化研究的核心内容。2005年启动的全球土地计划（Global Land Project, GLP）,不仅强调了人类—环境耦合系统的集成与模拟,还强调了不同管理模式和政策对土地覆被的影响[5,6]。土地利用覆被变化的动态监测与研究逐渐成为了全球气候和环境变化研究关注的重要内容。
Turner BL, Lambin EricF, ReenbergAnette.The emergence of land change science for global environmental change and sustainability. , 2007, 104(52): 20666.
Land change science has emerged as a fundamental component of global environmental change and sustainability research. This interdisciplinary field seeks to understand the dynamics of land cover and land use as a coupled human-environment system to address theory, concepts, models, and applications relevant to environmental and societal problems, including the intersection of the two. The major components and advances in land change are addressed: observation and monitoring; understanding the coupled system-causes, impacts, and consequences; modeling; and synthesis issues. The six articles of the special feature are introduced and situated within these components of study.
Yao ZY, Zhang LJ, Tang SH, et al.The basic characteristics and spatial patterns of global cultivated land change since the 1980s. , 2017, 27(7): 771-785.
In this paper, we analyzed the spatial patterns of cultivated land change between 1982 and 2011 using global vector-based land use/land cover data.(1) Our analysis showed that the total global cultivated land area increased by 528.768×104 km~2 with a rate of 7.920×104 km~2/a, although this increasing trend was not significant. The global cultivated land increased fastest in the 1980 s. Since the 1980 s, the cultivated land area in North America, South America and Oceania increased by 170.854×104 km~2, 107.890×104 km~2, and 186.492×104 km~2, respectively. In contrast, that in Asia, Europe and Africa decreased by 23.769×104 km~2, 4.035×104 km~2 and 86.76×104 km~2, respectively. Furthermore, the cultivated land area in North America, South America and Oceania exhibited significant increasing trends of 7.236× 104 km~2/a, 2.780×104 km~2/a and 3.758×104 km~2/a, respectively. On the other hand, that of Asia, Europe and Africa exhibited decreasing trend rates of –5.641×104 km~2/a, –0.831×104 km~2/a and –0.595×104 km~2/a, respectively. Moreover, the decreasing trend in Asia was significant.(2) Since the 1980 s, the increase in global cultivated lands was mainly due to converted grasslands and woodlands, which accounted for 53.536% and 26.148% of the total increase, respectively. The increase was found in southern and central Africa, eastern and northern Australia, southeastern South America, central US and Alaska, central Canada, western Russia, northern Finland and northern Mongolia. Among them, Botswana in southern Africa experienced an 80%–90% increase, making it the country with the highest increase worldwide.(3) Since the 1980 s, the total area of cultivated lands converted to other types of land was 1071.946×104 km~2. The reduction was mainly converted to grasslands and woodlands, which accounted for 57.482% and 36.000%, respectively. The reduction occurred mainly in southern Sudan in central Africa, southern and central US, southern Russia, and southern European countries including Bulgaria, Romania, Serbia and Hungary. The greatest reduction occurred in southern Africa with a 60% reduction.(4) The cultivated lands in all the continents analyzed exhibited a trend of expansion to high latitudes. Additionally, most countries displayed an expansion of newly increased cultivated lands and the reduction of the original cultivated lands.
RenW, TianH, TaoB, et al.China's crop productivity and soil carbon storage as influenced by multifactor global change. , 2012, 18(9): 2945-2957.
Much concern has been raised about how multifactor global change has affected food security and carbon sequestration capacity in China. By using a process-based ecosystem model, the Dynamic Land Ecosystem Model (DLEM), in conjunction with the newly developed driving information on multiple environmental factors (climate, atmospheric CO2, tropospheric ozone, nitrogen deposition, and land cover/land use change), we quantified spatial and temporal patterns of net primary production (NPP) and soil organic carbon storage (SOC) across China's croplands during 1980–2005 and investigated the underlying mechanisms. Simulated results showed that both crop NPP and SOC increased from 1980 to 2005, and the highest annual NPP occurred in the Southeast (SE) region (0.32 Pg C yr611, 35.4% of the total NPP) whereas the largest annual SOC (2.29 Pg C yr611, 35.4% of the total SOC) was found in the Northeast (NE) region. Land management practices, particularly nitrogen fertilizer application, appear to be the most important factor in stimulating increase in NPP and SOC. However, tropospheric ozone pollution and climate change led to NPP reduction and SOC loss. Our results suggest that China's crop productivity and soil carbon storage could be enhanced through minimizing tropospheric ozone pollution and improving nitrogen fertilizer use efficiency.
Tian HQ, RenW, TaoB, et al.Climate extremes and ozone pollution: A growing threat to China's food security. , 2016, 2(1): 1-10.
Abstract Ensuring global food security requires a sound understanding of climate and environmental controls on crop productivity. The majority of existing assessments have focused on physical climate variables (i.e., mean temperature and precipitation), but less on the increasing climate extremes (e.g., drought) and their interactions with increasing levels of tropospheric ozone (O3). Here we quantify the combined impacts of drought and O3 on China's crop yield using a comprehensive, process-based agricultural ecosystem model in conjunction with observational data. Our results indicate that climate change/variability and O3 together led to an annual mean reduction of crop yield by 10.0% or 55 million tons per year at the national level during 1981 2010. Crop yield shows a growing threat from severe episodic droughts and increasing O3 concentrations since 2000, with the largest crop yield losses occurring in northern China, causing serious concerns in food supply security in China. Our results imply that reducing tropospheric O3 levels is critical for securing crop production in coping with increasing frequency and severity of extreme climate events such as droughts. Improving air quality should be a core component of climate adaptation strategies.
ChenLigen.Sustainable development of agriculture and sustainable use of farmland resources in China. , 2001, 28(1): 102-105.
In this paper,the author put forward four features of sustainable development of agriculture,and that the farmland resources are the base for sustainable development of agriculture in China.Based on the problems of farmland use,the author also put forward some countermeasures for sustainable development of agriculture and sustainable use of farmland.
PengJ, Liu YX, Li TY, et al.Regional ecosystem health response to rural land use change: A case study in Lijiang City, China. , 2017, 72: 399-410.
QiaoMu, ChenMo, JililiMaimaiti, et al.Classification of agricultural landform in Xinjiang: Taking the mapping of agricultural geomorphologic map of 1:100000 in Xinjiang as an example. , 1994, 17(4): 53-61.
FuJinxia, ChangQingrui, LiFenling, et al.Evaluation of farmland productivity in complex topography regions of Loess Plateau based on GIS: A case study in Chengcheng County of Shaanxi Province. Geography and , 2011, 27(4): 57-61.
Supported by the key knowledge innovation projects,i.e., a preliminary study on the theories and techniques of the remotely sensed temporal-spatial information and digital Earth; and a study on the integration of national resources and environment and data sharing, the authors have set up a spatial-temporal information platform by the integration of the corresponding scientific and research achievements during the periods of the 8th- and 9th-Five Year Plan, which comprehensively reflected the features of land-use change, designed a series of technical frameworks on the spatial-temporal database construction based on remote sensing techniques, e.g., the construction of remotely sensed database and land-use spatial database of the mid-1980s, the mid-1990s and the end of the 1990s, which laid a foundation for the dynamic monitoring of land-use change and the corresponding studies. In this paper,the authors have analyzed comprehensively the features of land-use change in the 1990s, revealed the spatial-temporal change of land use supported by remote sensing and GIS technologies as well as analyzed the geophysical and socio-economic driving factors.The findings are as follows: the arable land has been increased in total amount, the balance of decrease in the south and increase in the north was resulted from the reclamations of grassland and forest land. On the whole, the forest land area had a process of decrease, and the decreased area was mainly distributed in the traditional forest areas. Areas with plentiful precipitation and heat in the south, however, had distinct effects of reforestation. The rural-urban construction land had a situation of persistent expansion, and the general expansion speed has been slowed down during the last five years of the 1990s with the exception of the Western China where the expansion speed has been accelerated. The land use change in China in the 1990s had distinct temporal and spatial differences due to two main reasons, which were policy control and economic driving. Hereby, conclusions and proposals brought forward by the authors were as follows: the spatial diversity rules of the modern land use change in China must be fully considered in the future land use planning. At the same time, the pertinence of physical geographical zones must be considered during the planning of eco-environment construction. And, based on the increasingly maturity of the infrastructure, the traditional thoughts on planning and management of resources must be shifted so as to fully realize the optimized allocation of land resources at regional scale.