吉林省耕地变化对粮食生产的影响

1IntroductionThe quantity and quality of cropland guarantees the grain production (Feng, 2000), and the essence of cropland security is food security. Cropland security means the stability of total quantity of cropland, which also means stable quality, potential productivity and regional balance (Feng, 2000). With the development of urbanization and industrialization, more and more cropland is encroached, especially the cropland with great market-value (Cai, 2000; Ge, 2002; Richard, 2002), w…     

A Local Example of Land-Use Change: Southern Illinois—1807, 1938, and 1993*

Abstract

This article provides an analysis of a wetland site in southern Illinois from presettlement to the present. The study area is part of the Cache River-Cypress Creek Wetland, which has international importance, as recognized by the Ramsar Convention on Wetlands. Land-cover data for 1807, 1938, and 1993 were created and analyzed with a geographic information system (GIS). Land-use change by topographic setting (uplands, transitional, and bottomlands) and soil productivity was quantified and studied. Interviews with local experts informed this analysis. Results illustrate the complexity of environmental change and its driving forces. First, notable forest and swamp acreage was converted to cropland between 1807 and 1938 and, to a lesser degree, from 1938 to 1993. Second, there were land-use variations by topographic region. Between 1807 and 1938, the largest transformation occurred in the uplands, with substantial acreage converted from forest to cropland. Between 1938 and 1993, however, agriculture decreased in the upland areas as hilly areas reverted to forest cover. At the same time, agriculture expanded in the bottomlands as this land was drained for farming. Third, there are interesting patterns within these categories of land-use change, as soil productivity is an indicator of what lands were taken out of cropland and converted back to grassland and forest.     

北京丰台区土地利用变化及其经济驱动力分析

采用GIS技术和统计分析技术,基于1984、1992和1995～2001年土地利用图件和数据,分析了1984年以来北京丰台区土地利用变化历史过程及其空间分异特征。土地利用变化的基本特点是农业用地面积大幅度下降,非农用地面积快速增加,且随着时间的推移,变化高峰地域在由内向外传递。对1999年土地利用类型数据与经济产值数据匹配结果表明:土地经济产出效益巨大差异的存在是驱动丰台区土地利用从农业用地,尤其是耕地向非农业用地转化的最大动力所在。利用1992～2001年的非农业用地与固定资产投资、人口,二、三产业增加值进行的相关分析显示,固定资产投资、人口增长和第二产业的发展对非农业用地扩展有着显著的作用。     

近300年中国耕地数据集重建与耕地变化分析

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42.4×10⁶ hm²增加至1985年的136.9×10⁶ hm²,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。     

Spatio-temporal analysis of cropland change in the Guanzhong area,China, from 1650 to 2016

As one of the most critical impact factors of global change, historical land-use change is an indispensable input in climate and environment simulations. To better understand the cropland change in the Guanzhong area, gazetteers, statistics, and survey data were collected as data sources. Methods of registered tax-paying cropland data collection, selection of time points, and data interpolation and calibration were used to reconstruct changes in the cropland area. The cropland area data at the county level were allocated to 1 km×1 km grid cells. The total cropland area in the Guanzhong area was influenced by changes in population, wars, natural disasters, and land-use types, and it fluctuated from 1650 to 2016. From 1780 to 1830, the cropland expanded in the northern and western parts of Guanzhong area, and the cropland in the north of Qinling Mountains increased slightly. The spatial pattern of cropland reached its maximum range in 1980, and the cropland area declined in the whole study area, especially in the cities of Xi'an and Xianyang in 2016. The comparison between HYDE 3.2 and the data obtained in this study showed that the grid cells of HYDE 3.2 exhibit lower values of cropland area fractions in the Guanzhong Basin and higher values in high-altitude areas around the Guanzhong Basin as compared to those in this study.     

1995–2015年陕北黄土丘陵区土地利用变化的垂直分布格局测度（英文）

The mountainous and hilly region plays an important role in ecological safety and production in China. However, recent studies have poorly characterized the parallel structure of land use in the valleys of the mountainous and hilly region using topographic factors(e.g.elevation, slope, aspect). Here, the loess hilly region of northern Shaanxi Province is used as a representative case area to analyze the vertical distribution pattern of land-use conversion using the relative elevation concept and the HAND index. The differences in the vertical structure of land-use conversion between absolute elevation and relative elevation were compared. We found that the classifications of absolute and relative elevation had similar proportions of each relative elevation grade in each absolute elevation grade. Cropland,woodland, and grassland were distributed evenly in each grade of absolute/relative elevation,while water body, built-up land and unused land were more likely to spread in low grades of relative elevation than those of absolute elevation. The land-use conversion(i.e. loss of cropland and gain in woodland and built-up land) showed an apparently stepped distribution with relative elevation classification, suitable for revealing vertical distributions of land-use conversion in the loess hilly region. Cropland transformed to woodland was mainly distributed in high grade of relative elevation, decreasing with a decrease in grades, while built-up land transformed from cropland and grassland was mainly distributed in low grade of relative elevation, decreasing with increases in grades. The grade of relative elevation where cropland transformed to woodland descended with the implementation of the Grain for Green Project. Our results suggest that it is better to analyze the vertical distribution of land-use conversion with relative elevation classification in hilly regions.     

塔里木盆地南缘和田地区土地利用变化的遥感研究

中国西部干旱区土地利用变化显著,是全球土地变化科学研究的热点区,为此论文基于1990—2016年4个时段的遥感卫星数据,采用面向对象的分层分类影像解译方法完成了塔里木盆地南缘和田地区(简称和田塔里木地区)土地利用调查,重点分析土地利用变化特征、发展模式和区域差异性。结果表明：1990—2016年,和田塔里木地区耕地持续加速扩张(增长率为2.9%/a),呈现渐进式扩张和骤变式开垦2种发展模式;建设用地面积增加(12.1%/a),主要表现为城市化发展、农村居民用地和交通用地的增加;耕地和建设用地扩张导致林灌草地和未利用地面积减少;和田地区县域土地利用发展不均衡,和田市建设用地比例最高,和田县与墨玉县的农业和建设用地扩张总量和速率最大,其次是洛浦县和于田县,皮山县、策勒县和民丰县农业和建设用地增长相对缓慢;总体上,和田塔里木地区耕地和建设用地的扩张在新疆处于一个较快的发展水平,今后一段时期快速的土地利用变化可能引起的生态环境问题需要重点关注。     

Spatiotemporal patterns and characteristics of land-use change in China during 2010–2015

Land use/cover change is an important theme on the impacts of human activities on the earth systems and global environmental change. National land-use changes of China during 2010–2015 were acquired by the digital interpretation method using the high-resolution remotely sensed images, e.g. the Landsat 8 OLI, GF-2 remote sensing images. The spatiotemporal characteristics of land-use changes across China during 2010–2015 were revealed by the indexes of dynamic degree model, annual land-use changes ratio etc. The results indicated that the built-up land increased by 24.6×10³ km² while the cropland decreased by 4.9×10³ km², and the total area of woodland and grassland decreased by 16.4×10³ km². The spatial pattern of land-use changes in China during 2010–2015 was concordant with that of the period 2000–2010. Specially, new characteristics of land-use changes emerged in different regions of China in 2010–2015. The built-up land in eastern China expanded continually, and the total area of cropland decreased, both at decreasing rates. The rates of built-up land expansion and cropland shrinkage were accelerated in central China. The rates of built-up land expansion and cropland growth increased in western China, while the decreasing rate of woodland and grassland accelerated. In northeastern China, built-up land expansion slowed continually, and cropland area increased slightly accompanied by the conversions between paddy land and dry land. Besides, woodland and grassland area decreased in northeastern China. The characteristics of land-use changes in eastern China were essentially consistent with the spatial govern and control requirements of the optimal development zones and key development zones according to the Major Function-oriented Zones Planning implemented during the 12th Five-Year Plan (2011–2015). It was a serious challenge for the central government of China to effectively protect the reasonable layout of land use types dominated with the key ecological function zones and agricultural production zones in central and western China. Furthermore, the local governments should take effective measures to strengthen the management of territorial development in future.     

榆林市农业景观格局变化研究

根据1986年和2000年两期TM影像资料和其他辅助资料, 运用人机交互解译方法以及地理信息系统的空间分析和数理统计功能, 分析了榆林市农业景观格局变化, 包括土地利用数量变化、变化速度和区域差异等特征, 以及各景观类型之间的转化情况, 并对景观格局变化进行了定量分析。结果表明: 14a间, 榆林市未利用地减少1305.56km², 其中主要是沙地减少; 耕地、林地、草地分别增加567.11km²、99.6km²和616.79km²; 未利用地和建设用地的变化率最大, 分别为-22.11%和18.18%; 土地利用变化存在明显的区域差异; 各类型间的转化突出表现为未利用地向草地转化, 草地向林地和耕地转化。榆林市近十几年景观类型发生了明显转换, 土地整治取得显著成绩。     

基于遥感技术和GIS的小流域土地利用/覆被变化分析

根据贵州省平坝县克酬流域1973年MSS影像数据,1989、1995、2000年Landsat TM影像数据,利用RS和GIS信息获取技术、空间分析技术和数理统计方法,分析了该流域土地利用的数量变化和空间变化特征,明确了土地利用变化的主要类型和方向,并探讨了土地利用变化和地形因子的关系。结果显示,该流域土地利用以农田和灌草用地为主,1973~2000年林地和灌草地减少,农田、水域、村镇、交通用地增加,林地转化为灌草、灌草转化为农田及农田转化为村镇居民点和公路用地是研究区主要土地利用变化类型。研究区土地利用空间分布与海拔高程、坡度等地形因子有密切关系。1973~2000年农田、林地和灌草分布的海拔高程和坡度均呈增加趋势,这和上述土地利用类型间的转化规律相一致。     

Spatiotemporal characteristics,patterns, and caus-es of land-use changes in China since the late 1980s

Land-use/land-cover changes (LUCCs) have links to both human and nature interactions. China's Land-Use/cover Datasets (CLUDs) were updated regularly at 5-year intervals from the late 1980s to 2010,with standard procedures based on Landsat TM\ETM+ images. A land-use dynamic regionalization method was proposed to analyze major land-use conversions. The spatiotemporal characteristics,differences,and causes of land-use changes at a national scale were then examined. The main findings are summarized as follows. Land-use changes (LUCs) across China indicated a significant variation in spatial and temporal characteristics in the last 20 years (1990-2010). The area of cropland change decreased in the south and increased in the north,but the total area remained almost unchanged. The reclaimed cropland was shifted from the northeast to the northwest. The built-up lands expanded rapidly,were mainly distributed in the east,and gradually spread out to central and western China. Woodland decreased first,and then increased,but desert area was the opposite. Grassland continued decreasing. Different spatial patterns of LUC in China were found between the late 20th century and the early 21st century. The original 13 LUC zones were replaced by 15 units with changes of boundaries in some zones. The main spatial characteristics of these changes included (1) an accelerated expansion of built-up land in the Huang-Huai-Hai region,the southeastern coastal areas,the midstream area of the Yangtze River,and the Sichuan Basin;(2) shifted land reclamation in the north from northeast China and eastern Inner Mongolia to the oasis agricultural areas in northwest China;(3) continuous transformation from rain-fed farmlands in northeast China to paddy fields;and (4) effectiveness of the "Grain for Green" project in the southern agricultural-pastoral ecotones of Inner Mongolia,the Loess Plateau,and southwestern mountainous areas. In the last two decades,although climate change in the north affected the change in cropland,policy regulation and economic driving forces were still the primary causes of LUC across China. During the first decade of the 21st century,the anthropogenic factors that drove variations in land-use patterns have shifted the emphasis from one-way land development to both development and conservation.The "dynamic regionalization method" was used to analyze changes in the spatial patterns of zoning boundaries,the internal characteristics of zones,and the growth and decrease of units. The results revealed "the pattern of the change process," namely the process of LUC and regional differences in characteristics at different stages. The growth and decrease of zones during this dynamic LUC zoning,variations in unit boundaries,and the characteristics of change intensities between the former and latter decades were examined. The patterns of alternative transformation between the "pattern" and "process" of land use and the causes for changes in different types and different regions of land use were explored.     

近50年来松嫩平原西部土地利用变化及驱动力分析

在遥感和地理信息系统技术支持下,对松嫩平原西部土地利用方式、景观格局的动态变化进行定量研究。结果表明:过去近50年里,松嫩平原西部耕地净增加29.65×10⁴hm²,其中草地与湿地对耕地的增加贡献最大;草地减少70.29×10⁴ hm²,除部分草地转化为耕地外,退化为盐碱地、沙地也是草地大量减少的一个重要原因;松嫩平原西部现有沼泽湿地面积44.88×10⁴ hm²,近50年来减少62.54%。景观破碎化严重,不同土地利用类型间频繁转化,表明各种土地景观间存在不稳定因素,自然和人为因子在景观的转化中有不可忽略的作用,但人为因子的作用更显著。     

WRF模拟的1980-2000年中国东北农业开发对气候的影响

利用WRF模式,基于中国东北1980年代前期和2000年的土地利用/覆盖数据,分别进行了1980-2000年的气候变化模拟试验。通过两个试验结果的对比,分析了1980-2000年中国东北农业开发对气候的影响。在冬季和春季,农业开发使地表反照率增强,地表吸收的短波辐射减少,地表感热通量相应减少,地表气温降低;在夏季和秋季,农业开发削弱了地表反照率,地表吸收的短波辐射增加,同时地表潜热通量大幅增加,且增幅大于地表吸收的短波辐射的增幅,地表感热通量则相应减少,地表气温降低。农业开发的致冷幅度大多为0.1°C~1.0°C,与同期大尺度气候变化导致的当地背景温度变幅基本相当。农业开发引起的夏季降水变化因气候年景而异,“南旱北涝”年景下,呼伦贝尔—黑龙江省中部以及吉林省中部少雨,黑、吉、蒙三省（自治区）交界处降水增加,辽、蒙交界处以及辽东湾北部降水减少;“南涝北旱”年景下,呼伦贝尔—黑龙江省中部以及吉林省中部多雨,黑、吉、蒙三省（自治区）交界处降水减少,辽、蒙交界处以及辽东湾北部降水减少。农业开发的面积极其有限,因而由其导致的温度和降水显著变化主要出现在农业开发当地,尚不足以显著影响区域平均温度和降水变化。     

2010-2015年中国土地利用变化的时空格局与新特征

土地利用/覆被变化是人类活动对地球表层及全球变化影响研究的重要内容。本文基于Landsat 8 OLI、GF-2等遥感图像和人机交互解译方法,获取的土地利用数据实现了中国2010-2015年土地利用变化遥感动态监测。应用土地利用动态度、年变化率等指标,从全国和分区角度揭示了2010-2015年中国土地利用变化的时空特征。结果表明：2010-2015年中国建设用地面积共增加24.6×10³ km²,耕地面积共减少4.9×10³ km²,林草用地面积共减少16.4×10³ km²。2010-2015年与2000-2010年相比,中国土地利用变化的区域空间格局基本一致,但分区变化呈现新的特征。东部建设用地持续扩张和耕地面积减少,变化速率有所下降;中部建设用地扩张和耕地面积减少速度增加;西部建设用地扩张明显加速,耕地面积增速进一步加快,林草面积减少速率增加;东北地区建设用地扩展持续缓慢,耕地面积稳中有升,水旱田转换突出,林草面积略有下降。从“十二五”期间国家实施的主体功能区布局来看,东部地区的土地利用变化特征与优化和重点开发区的国土空间格局管控要求基本吻合;中部和西部地区则面临对重点生态功能区和农产品主产区相关土地利用类型实现有效保护的严峻挑战,必须进一步加大对国土空间开发格局的有效管控。     

River channel response to short-term human-induced change in landscape connectivity in Andean ecosystems

The drainage basin of the Deleg River (88 km²), located in the southern Ecuadorian Andes, was studied to assess the geomorphic and hydrologic response of a fluvial system to human-induced environmental change in its contributing area. Historical data on land use, channel morphology and sedimentology were collected, based on a spatial analysis of aerial photographs (1963–1995) and a field survey (2002). Analysis of channel cross-sectional profiles and sedimentological data revealed a major change in morphology and sedimentology of the Deleg River during the past four decades: (i) the active river channel narrowed by over 45%, (ii) the riverbed incised on average by over 1.0 m and (iii) the median grain size of the bed surface decreased from 13.2 cm to 4.7 cm. The spatial pattern of land cover within the Deleg catchment also changed considerably: highly degraded agricultural land in the low-lying areas was abandoned and partially afforested for timber and wood production, whereas secondary upland forest was increasingly cleared for expansion of cropland and pastures. Notwithstanding large changes in the spatial organization of land use within the catchment, the overall land use did not change significantly during the past four decades. This suggests that the response of the Deleg River to land-use change not only depends on the overall land-use change, but also on the spatial pattern of land-use/cover change within the catchment. Although forestation and regeneration of bare gully slopes and floors throughout the catchment only represented a minor part of the total land-use change, these land-use/cover changes had a major impact on the hydrological and sediment connectivity in the landscape.     

Spatiotemporal characteristics,patterns and causes of land use changes in China since the late 1980s简

Land-use/land-cover changes （LUCCs） have links to both human and nature inter- actions. China＇s Land-Use/cover Datasets （CLUDs） were updated regularly at 5-year inter- vals from the late 1980s to 2010, with standard procedures based on Landsat TM／ETM＋ im- ages. A land-use dynamic regionalization method was proposed to analyze major land-use conversions. The spatiotemporal characteristics, differences, and causes of land-use changes at a national scale were then examined. The main findings are summarized as fol- lows. Land-use changes （LUCs） across China indicated a significant variation in spatial and temporal characteristics in the last 20 years （1990-2010）. The area of cropland change de- creased in the south and increased in the north, but the total area remained almost un- changed. The reclaimed cropland was shifted from the northeast to the northwest. The built-up lands expanded rapidly, were mainly distributed in the east, and gradually spread out to central and western China. Woodland decreased first, and then increased, but desert area was the opposite. Grassland continued decreasing. Different spatial patterns of LUC in China were found between the late 20th century and the early 21st century. The original 13 LUC zones were replaced by 15 units with changes of boundaries in some zones. The main spatial characteristics of these changes included （1） an accelerated expansion of built-up land in the Huang-Huai-Hai region, the southeastern coastal areas, the midstream area of the Yangtze River, and the Sichuan Basin; （2） shifted land reclamation in the north from northeast China and eastern Inner Mongolia to the oasis agricultural areas in northwest China; （3） continuous transformation from rain-fed farmlands in northeast China to paddy fields; and （4） effective- ness of the ＂Grain for Green＂ project in the southern agricultural-pastoral ecotones of Inner Mongolia, the Loess Plateau, and southwestern mountainous areas. In the last two decades, although climate change in the north affected the change in cropland, policy regulation and economic driving forces were still the primary causes of LUC across China. During the first decade of the 21st century, the anthropogenic factors that drove variations in land-use pat- terns have shifted the emphasis from one-way land development to both development and conservation. The ＂dynamic regionalization method＂ was used to analyze changes in the spatial patterns of zoning boundaries, the internal characteristics of zones, and the growth and decrease of units. The results revealed ＂the pattern of the change process,＂ namely the process of LUC and regional differences in characteristics at different stages. The growth and decrease of zones during this dynamic LUC zoning, variations in unit boundaries, and the characteristics of change intensities between the former and latter decades were examined. The patterns of alternative transformation between the ＂pattern＂ and ＂process＂ of land use and the causes for changes in different types and different regions of land use were explored.     

土地利用动态与风力侵蚀动态对比研究——以内蒙古自治区为例

内蒙古是我国土壤风力侵蚀较为严重的地区之一,同时也是我国土地利用方式剧烈变化的地区之一。依据两期土地利用数据以及相应年代的土壤风力侵蚀数据,研究了20世纪90年代末期内蒙古自治区土地利用和风力侵蚀的静、动态格局。根据土地利用和风力侵蚀的空间分布及动态变化特点,设计了内蒙古土地利用-风力侵蚀动态区划,基于该区划详细讨论了内蒙古不同地区占主导地位的土地利用动态与风力侵蚀动态,由此揭示了两者之间存在的驱动--被驱动关系。研究发现,在20世纪90年代末期,内蒙古土地利用和风力侵蚀的基本格局没有太大变化,但风力侵蚀强度在总体上增强了;土地利用的变化主要反映为草地的退化和耕地的扩张。土地利用动态与风力侵蚀动态有着良好的时空对应关系:草地的退化与耕地的扩张导致了显著的风力侵蚀增强,而草地的改善以及耕地的收缩对风力侵蚀的影响不如前者明显,这表明了土地利用动态对风力侵蚀动态正、反向驱动的不平衡性。     

榆林地区土地利用/覆被变化区域特征及其驱动机制分析

利用榆林地区1986、1995年土地利用现状图,在地理信息系统支持下建立土地利用变化转移矩阵,结合多年社会统计资料分析榆林地区10多年来的土地利用动态变化特征。研究结果表明：土地利用类型变化幅度大、流转方向较为集中,具体表现为农田总面积下降、耕地质量局部改善,林草覆盖面积增长、其它用地类型面积减少;从区域角度分析,南部黄土丘陵沟壑区耕地面积减少、成熟林地面积增加幅度大与西北部风沙区耕地面积轻微增加、天然草地优势地位增强形成鲜明对比,这种区域特征符合“因地制宜”规律,与“退耕还林还草”政策导向吻合。全区总人口及其区域分布、农民年均收入和农业人口比重为该区土地利用／覆被变化的主要驱动力,同时人们的环境保护意识和相应的土地政策也对该区土地利用／覆被变化产生较大影响。     

北京丰台区农村居住用地变化及与人口相关模型

采用GIS技术和统计分析技术，基于1984年，1992年，1996年和1999年4期土地利用图件和数据，分析了1984－1999年期间北京丰台区农村居住用地变化过程及地域分异特征；提出并应用特征均值探讨了农村人均居住用地和人居密度变化的过程和趋势，以行政村为基本单元，利用1999年农村居住用地数据与对应的农村人口数据建立了表达式为Sv=11.324e^0.0006pv的农村居住用地与人口相关模型；用1992年数据对模型进行检验和误差分析的结果表明，模型适用地域为北京近郊且不邻近卫星城镇的农村区。     

基于遥感的中国陕北地区近20年耕地变化及其对农田生产力影响的定量评估

本文以中国退耕还林生态工程重点区域陕北地区作为研究区,对比其前后两个10年的耕地资源空间分布格局,并进一步分析耕地变化对农田生产力的影响。论文基于中高分辨率卫星遥感数据,经人机交互目视解译并结合实地验证,生成陕北地区1990、2000和2010年耕地现状以及前后两个10年耕地变化时空监测数据集。进而运用光能利用率遥感模型,结合中分辨率、长时间序列卫星遥感数据估算陕北地区农田净初级生产力,分析耕地变化对农田生产力的影响。结果表明,陕北地区耕地面积及其生产力在研究期前10年小幅增长,后10年明显减少。耕地增加的主要原因是为满足当地人口的粮食需求以及弥补城市建设对耕地的占用,大面积草地和未利用地被开垦。耕地减少的最主要原因是生态退耕,城市化也是耕地减少的原因之一。总体而言,20年来陕北地区耕地资源总面积净减少42.56%;受耕地面积变化的影响,同期农田净初级生产力下降了41.90%。研究对于评估陕北地区耕地安全和粮食安全,指导区域土地利用科学规划具有重要意义。