中国东北玉米空间分布对气候变化的响应,1980–2010（英文）

Based on county-level crop statistics and other ancillary information,spatial distribution of maize in the major maize-growing areas(latitudes 39°–48°N) was modelled for the period 1980–2010 by using a cross-entropy-based spatial allocation model.Maize extended as far north as the northern part of the Lesser Khingan Mountains during the period,and the area sown to maize increased by about 5 million ha.More than half of the increase occurred before 2000,and more than 80% of it in the climate transitional zone,where the annual accumulated temperature(AAT) was 2800–3400 °C·d.Regions with AAT of 3800–4000 °C·d became more important,accounting for more than 25% of the increase after 2000.The expansion of maize was thus closely related to warming,although some variation in the distribution was noticed across zones in relation to the warming,indicating that maize in northeast China may have adapted successfully to the warming by adjusting its spatial distribution to match the changed climate.     

Change analysis of rice area and production in China during the past three decades

Rice＇s spatial-temporal distributions, which are critical for agricultural, environ- mental and food security research, are affected by natural conditions as well as socio-eco- nomic developments. Based on multi-source data, an effective model named the Spatial Production Allocation Model （SPAM） which integrates arable land distribution, administrative unit statistics of crop data, agricultural irrigation data and crop suitability data, was used to get a series of spatial distributions of rice area and production with 10-km pixels at a national scale -it was applied from the early 1980s onwards and used to analyze the pattern of spatial and temporal changes. The results show that significant changes occurred in rice in China during 1980-2010. Overall, more than 50% of the rice area decreased, while nearly 70% of rice production increased in the change region during 1980-2010. Spatially, most of the increased area and production were in Northeast China, especially, in Jilin and Heilongjiang; most of the decreased area and production were located in Southeast China, especially, in regions of rapidly urbanization in Guangdong, Fujian and Zhejiang. Thus, the centroid of rice area was moved northeast approximately 230 km since 1980, and rice production about 320 km, which means rice production moved northeastward faster than rice area because of the significant rice yield increase in Northeast China. The results also show that rice area change had a decisive impact on rice production change. About 54.5% of the increase in rice pro- duction is due to the expansion of sown area, while around 83.2% of the decrease in rice production is due to contraction of rice area. This implies that rice production increase may be due to area expansion and other non-area factors, but reduced rice production could largely be attributed to rice area decrease.     

Remote sensing monitoring on regional crop water productivity in the Haihe River Basin

Crop water productivity （CWP） agricultural development in water scarcity is one of the important indicators for sustainable area. There is serious conflict between water sup- ply and requirement in the Haihe River Basin. CWP of winter wheat and summer maize from 2003 to 2007 in the Haihe River Basin is estimated based on large-scale evapotranspiration （ET） and crop yield obtained by remote sensing technology. Spatial and temporal distribution of CWP of winter wheat and summer maize is investigated in this study. Results show that CWP of winter wheat in most parts of the study area varies from 1.02 kg/m3 to 1.53 kg/m3, and CWP of summer maize varies from 1.31 kg/m3 to 2.03 kg/m3. Multi-year averaged CWP of winter wheat and summer maize in the study area is about 1.19 kg/m3 and 1.59 kg/m3. CWP results show certain promotion potential to alleviate the water shortage in the Haihe River Basin. Correlation analysis of CWP, crop yield and ET shows that there is great potential for crop yield promotion without the growth in irrigation water. Large-scale CWP estimated by remote sensing technology in this study shows spatial distribution features, which could be used to real-time agricultural water resource management combined with crop yield and ET.     

1949–2014年中国三种主要作物的地理重心时空迁移分析（英文）

Spatial distribution changes in major crops can reveal important information about cropping systems.Here,a new centroid method that applies physics and mathematics to spatial pattern analysis in agriculture is proposed to quantitatively describe the historical centroids of rice,maize and wheat in China from 1949 to 2014.The geographical centroids of the rice area moved 413.39 km in a 34.32° northeasterly(latitude 3.08°N,longitude 2.10°E) direction at a speed of 6.36 km/year from central Hunan province to Hubei province,while the geographical centroids of rice production moved 509.26 km in the direction of 45.44° northeasterly(latitude 3.22°N,longitude 3.27°E) at a speed of 7.83 km/year from central Hunan province to Henan province.The geographical centroids of the maize area and production moved 307.15 km in the direction of 34.33° northeasterly(latitude 2.29°N,longitude 1.56°E) and 308.16 km in the direction of 30.79° northeasterly(latitude 2.39°N,longitude 1.42°E),respectively.However,the geographical centroids of the wheat area and production were randomly distributed along the border of Shanxi and Henan provinces.We divided the wheat into spring wheat and winter wheat and found that the geographical centroids of the spring wheat area and production were distributed within Inner Mongolia,while the geographical centroids of winter wheat were distributed in Shanxi and Henan provinces.We found that the hotspots of crop cultivation area and production do not always change concordantly at a larger,regional scale,suggesting that the changing amplitude and rate of each crops' yield differ between different regions in China.Thus,relevant adaptation measures should be taken at a regional level to prevent production damage in those with increasing area but decreasing production.     

中国东北地区林地面积变化的动态模拟

There is plenty of forests in Northeast China which contributes a lot to the conservation of water and land resources, produces timber products, and provides habitats for a huge number of wild animals and plants. With changes of socio-economic factors as well as the geophysical conditions, there are dramatic changes on the spatial patterns of forest area. In this sense, it is of great significance to shed light on the dynamics of forest area changes to find the underlining reasons for shaping the changing patterns of forest area in Northeast China. To explore the dynamics of forest area change in Northeast China, an econometric model is developed which is composed of three equations identifying forestry production, conversion from open forest to closed forest and conversion from other land uses to closed forest so as to explore the impacts on the forest area changes from demographic, social, economic, location and geophysical factors. On this basis, we employ the Dynamics of Land System (DLS) model to simulate land-use conversions between forest area and non-forest cover and the land-use conversions within the sub-classes of forest area for the period 2000–2020 under business as usual scenario, environmental protection scenario and economic growth scenario. The simulation results show that forest area will expand continuously and there exist various kinds of changing patterns for the sub-classes of forest area, for example, closed forest will expand continuously and open forest and shrub will decrease a little bit, while area of other forest will keep intact. The research results provide meaningful decision-making information for conserving and exploiting the forest resources and making out the planning for forestry production in the Northeast China region.     

Photosynthetic pigments accumulation and some growth indices of cowpea, maize and tomato in response to interspecific and intraspecific competition stress

This study aimed at investigating the photosynthetic pigment accumulation and some growth indices of cowpea, maize and tomato in response to interspecific and intraspecific competition stress. The study was carried out under a screen-house to minimize extraneous factors such as pests and rodents using a randomized complete block design(RCBD). Seeds of cowpea, maize and tomato were collected from the Department of Crop Production and Protection, Faculty of Agriculture,Obafemi Awolowo University, Ile Ife, Osun state, Nigeria. These seeds were planted at a depth of about 3 mm below the soil. The seeds were sown at the rate of six seeds per pot in the monoculture, while in the pots designed for the mixed culture of maize and cowpea, maize and tomato, cowpea and tomato, three seeds of each plant were sown. Two seeds of each plant were sown in the pots with the three crops. The treatments were then supplied with 500 m L of tap water in the morning and in the evening respectively until the seedlings become fully established. The photosynthetic pigments were determined spectrophotometrically with three replicates. Plant growth indices were determined according to Hunts(1978) using leaf area and dry matter data collected at four and six weeks after planting. Statistical analysis was performed using statistical analytical software SAS version 9.2. The results indicated that photosynthetic pigments accumulation(Chlorophyll a, b and carotenoid) in maize(15.98, 23.92 and 44.72 μM), Chlorophyll b and carotenoid in tomato plants(12.48 and 1,178.7μM) in the sole stands were more than the mixed culture of maize with cowpea and tomato(7.195, 14.74 and 0.00 μM).Also, total Chlorophyll in maize(1,127.8 μM), Chlorophyll a and total Chlorophyll in tomato(3.95 and 1,317.5 μM) in the mixed culture were more than in the sole culture of maize(1,030.9 μM) and tomato plants(-9.40 and 546.3 μM). The different photosynthetic pigments accumulated in cowpea were greatly enhanced in the mixed culture than in the sole culture.All the photosynthetic pigments of maize, cowpea and tomato in all the treatments analysed in this study were significantly different at P0.05. Plant growth indices such as net assimilation rate, relative growth rate, crop growth rate and tissue water contents of these plants had higher value in the intercropped than the check crop(sole). These plant growth indices were significantly different to one another at P0.05. This study concluded that competition for shared resources in the mixed culture of tomato, maize and cowpea enhanced growth and accumulation of photosynthetic pigments.     

Estimation of maize yield incorporating the synergistic effect of climatic and land use change in Jilin,China

Yield forecasting can give early warning of food risks and provide solid support for food security planning. Climate change and land use change have direct influence on regional yield and planting area of maize, but few studies have examined their synergistic impact on maize production. In this study, we propose an analysis framework based on the integration of system dynamic(SD), future land use simulation(FLUS) and a statistical crop model to prefuture maize yield variation in response to clim...     

1998-2008年中国农作物化肥消费的时空分异(英文)

The agricultural and land policies in China are always focused on protecting its food supply and security because of the country’s large population and improved diets.The crop production guide ’Take Grain as the Key Link’ prompted peasants to plant grain on most of the agricultural land,leading to the majority of fertilizer being used in grain crops for many years in China.This situation has changed dramatically in recent years.Based on data pertaining to provincial crops sown area and fertilizer use per unit area in 1998 and 2008,the temporal and spatial variations of China’s fertilizer consumption by crops were analyzed at the provincial level,and the results are presented here.(1) Fertilizer consumption in China grew strongly in the last decade,while the growth was mainly attributable to the increase of fertilizer con-sumption by horticultural crops.The fertilizer consumption of grain crops dropped from 71.0% in 1998 to 57.8% in 2008.Thus,it is concluded that the emphasis of fertilizer consumption is shifting toward horticultural crops.(2) There were marked differences in the growth rates of fertilizer consumption from the regional point of view.The national average growth rate of fertilizer consumption was 31.9% during 1998-2008.The western and northeastern parts of the country came close to the national average,while the eastern part was lower,with an average of 13.0%,and central China was much higher(50.8%).The increase of fertilizer consumption in central and west China was higher than the other zones,which already ac-counted for 77.9% of the national total.Thus,it is concluded that the consumption emphasis of chemical fertilizer shifts toward the central and western regions.(3) The decline of fertilizer consumption by grain crops was largely due to the decrease in sown area compared with the increase by vegetable crops attributable to the enlarging sown area;the increase by orchard crops was affected by both expanding the sown area and fertilizer use per unit area.     

河北平原冬小麦播种面积收缩对农业水资源消耗的影响(英文)

This study firstly analyzed the shrinkage of winter wheat and the changes of cropping systems in the Hebei Plain from 1998 to 2010 based on the agricultural statistic data of 11 cities and meteorological data, including daily temperature, precipitation, water vapor, wind speed and minimum relative humidity data from 22 meteorological stations, and then calculated the water deficit and irrigation water resources required by different cropping systems, as well as the irrigation water resources conserved as a result of cropping system changes, using crop coefficient method and every ten-day effective precipitation estimation method. The results are as follows. 1) The sown areas of winter wheat in the 11 cities in the Hebei Plain all shrunk during the study period. The shrinkage rate was 16.07% and the total shrinkage area amounted to 49.62×104ha. The shrinkage was most serious in the Beijing-Tianjin-Tangshan metropolitan agglomerate, with a shrinkage rate of 47.23%. 2) The precipitation fill rate of winter wheat was only 20%–30%, while those of spring maize and summer maize both exceeded 50%. The irrigation water resources demanded by the winter wheat-summer maize double cropping system ranged from 400 mm to 530 mm, while those demanded by the spring maize single cropping system ranged only from 160 mm to 210 mm. 3) The water resources conserved as a result of the winter wheat sown area shrinkage during the study period were about 15.96×108m3/a, accounting for 27.85% of those provided for Beijing, Tianjin and Hebei by the first phase of the Mid-Route of the South-to-North Water Diversion Project.     

A discussion on improving typhoon observation through radar by scanning the negative elevation angle

Certain feasibilities and features were discussed in typhoon detection by radar with a negative elevation angle according to the relationship between the remote detecting range and the elevation angle of the new generation weather radar, in order to rectify the disadvantages of detecting capability for remote low-level echo with a lowest elevation angle of 0.5° in the common detecting mode. The data obtained from detecting the typhoon of Haitang and Changmi with radar for their negative elevation angles and the observed data for the common lowest elevation angle of 0.5° were compared to each other. The results showed that the detection of remote low level cloud system with radar could be improved by using the negative elevation angle, and the structure and the evolution trend of a typhoon could be better judged. The increasing degree of detection for negative elevation angles in the current volume scanning mode should be helpful for predicting the intensity and developing trend of windstorms, to further improve the capability of warning and nowcasting. The detection of negative elevation angle could also help reveal the development and change of typhoon＇s low level cloud system. As far as the typhoons of Haitang and Changmi were concerned, the detecting area of Changmi was increased by 1.09 times with the negative elevation angle of 0.31°, compared with the elevation angle of 0.48° if the threshold value for the sea echo within 100 km was eliminated. Several volume scans of Haitang were increased by 2.1%-7.9% for the negative elevation angle of 0.36° compared with the elevation angle of 0.49° . Therefore, the radar detecting capability of typhoons could be improved by the detection of negative elevation angles to some extent. This could make up for the disadvantages of a low detecting capability for remote low-level echo in the common detecting mode. At the same time, a negative elevation angle could be easily influenced by the ground clutter and the close sea wave clutter which interfered with the asses     

基于作物空间分配模型的东北三省春玉米时空分布特征

利用1980-2010 年东北三省分县玉米播种面积与产量统计、耕地分布、农业灌溉分布以及作物适宜性分布等多源数据,结合基于交叉信息熵原理的作物空间分配模型（Spatial Production Allocation Model,SPAM）,在5'×5'的像元尺度模拟了春玉米种植面积与产量的时空分布,并重点分析了两者在纬向、经向,以及高程上的时空变化规律。结果显示：（1）玉米种植面积在2000 年前向北扩展至北纬44°~48°间,2000 年后在中南部出现大规模发展（北纬42°~44°）,并进一步向东扩展至东经123°~127°间,同时还表现为向低海拔（高程100 m以下）和较高海拔（高程200~350 m）扩展的态势;（2）单产在纬向上的增加区主要集中在北纬42°~48°,经向上的单产增加则相对均匀,高程上单产提升区主要集中在海拔350 m以下。（3）像元内玉米种植比例整体上由中低种植比例为主逐步演变为中高比例占据主体,并且中高种植比例像元对应的玉米单产水平整体上较高,反映了市场经济驱动下的玉米种植集聚化和规模化的发展趋势。     

Spatial distribution of maize in response to climate change in northeast China during 1980–2010

Based on county-level crop statistics and other ancillary information, spatial distribution of maize in the major maize-growing areas (latitudes 39°–48°N) was modelled for the period 1980–2010 by using a cross-entropy-based spatial allocation model. Maize extended as far north as the northern part of the Lesser Khingan Mountains during the period, and the area sown to maize increased by about 5 million ha. More than half of the increase occurred before 2000, and more than 80% of it in the climate transitional zone, where the annual accumulated temperature (AAT) was 2800–3400 °C·d. Regions with AAT of 3800–4000 °C·d became more important, accounting for more than 25% of the increase after 2000. The expansion of maize was thus closely related to warming, although some variation in the distribution was noticed across zones in relation to the warming, indicating that maize in northeast China may have adapted successfully to the warming by adjusting its spatial distribution to match the changed climate.     

东北西部粮食生产时空格局变化及优化布局研究

利用2003~2013年东北西部各县市粮食生产统计数据,运用聚类分析、粮食贡献度和PSR模型方法,分析东北西部粮食生产格局变化及其影响因素,根据国家“镰刀弯”地区规划提出的玉米种植面积调减目标,对各县市具体调减值进行核算,得出以下主要结论。从2003年以来,粮食播种面积和产量明显向玉米、水稻两种作物集中,而相对低产的大豆所占比例明显下降;粮食生产格局发生明显变化,多数地区被以玉米为主的类型区取代。2003~2013年东北西部粮食增产主要归因于种植面积扩大,其次是粮食单产提高,受粮食作物结构影响较小。东北西部耕地生态安全评价值均小于0.6,处于不安全级至临界安全级阈值范围内,其中不安全级和较不安全级所占比重为97.01%,集中呈片状分布,亟待调整区域种植结构以提高耕地生态安全。东北西部玉米播种面积调减总目标为145.20万hm²,其中农牧交错带调减113.23万hm²,冷凉区调减31.97万hm²,调减地区主要集中在赤峰市、通辽市、兴安盟、吉林西部和辽宁西部地区的部分县市等玉米为主的类型区。东北西部各县市在调减玉米种植面积的过程中,应充分考虑耕地生态安全、农民的生计替代和利益补偿等问题,做到科学、合理、有序地调减玉米种植面积。     

Spatio-temporal analysis of the geographical centroids for three major crops in China from 1949 to 2014

Spatial distribution changes in major crops can reveal important information about cropping systems. Here, a new centroid method that applies physics and mathematics to spatial pattern analysis in agriculture is proposed to quantitatively describe the historical centroids of rice, maize and wheat in China from 1949 to 2014. The geographical centroids of the rice area moved 413.39 km in a 34.32° northeasterly (latitude 3.08°N, longitude 2.10°E) direction at a speed of 6.36 km/year from central Hunan province to Hubei province, while the geographical centroids of rice production moved 509.26 km in the direction of 45.44° northeasterly (latitude 3.22°N, longitude 3.27°E) at a speed of 7.83 km/year from central Hunan province to Henan province. The geographical centroids of the maize area and production moved 307.15 km in the direction of 34.33° northeasterly (latitude 2.29°N, longitude 1.56°E) and 308.16 km in the direction of 30.79° northeasterly (latitude 2.39°N, longitude 1.42°E), respectively. However, the geographical centroids of the wheat area and production were randomly distributed along the border of Shanxi and Henan provinces. We divided the wheat into spring wheat and winter wheat and found that the geographical centroids of the spring wheat area and production were distributed within Inner Mongolia, while the geographical centroids of winter wheat were distributed in Shanxi and Henan provinces. We found that the hotspots of crop cultivation area and production do not always change concordantly at a larger, regional scale, suggesting that the changing amplitude and rate of each crops’ yield differ between different regions in China. Thus, relevant adaptation measures should be taken at a regional level to prevent production damage in those with increasing area but decreasing production.     

气候变化和物候变动对东北黑土区农业生产的协同作用及未来粮食生产风险

东北黑土区是中国重要的粮食生产基地,也是中国气候变化最敏感的地区之一。然而,气候变化背景下东北黑土区气候及物候变化对农业生产力的综合影响并不清晰,未来农业生产风险评估的定量化程度不够,风险等级制定缺乏依据。本文借助遥感产品、气候资料和模拟数据等资料,综合运用多元线性回归、相关分析及干旱危险性指数等方法,探究东北黑土区作物物候动态及其气候响应特征,辨识气候与物候变化对农业生产的复合效应及未来可能风险。结果表明：① 2000—2017年东北黑土区29.76%的区域作物生长季开始期呈显著延后趋势,16.71%的区域作物生长季结束期呈提前态势,生长季开始期受气温的影响范围广,且滞后时间长;生长季结束期与前期气候变化关系更加密切,且带状差异性响应格局尤其明显。② 气候变化和物候期改变对作物生产的解释能力较生长季同期气候变化的解释能力增加了70.23%,解释面积扩大了85.04%。③ RCP8.5情景下东北黑土区粮食总产量呈现上升趋势,粮食生产风险表现出“南增北减”的演变特征,风险区面积不断扩大,全球温升2.0 ℃时,松嫩黑土亚区南部粮食减产量可能达到10%。研究有助于深入认识气候—物候—作物生产的关联机理及未来粮食生产风险,对制定气候变化应对策略,保障国家粮食安全具有重要意义。     

2003~2014年中国种植业产值增长及贡献因素分析

基于统计数据,采用对数平均迪氏分解模型,从全国和省域2个尺度研究农作物播种面积、单位面积产值、增加值率、价格变化等因素对2003~2014年中国种植业增加值的影响方向与程度,以期为农业政策调整和差别化的种植业生产策略制定提供依据。结果表明：① 12 a间种植业增加值增加了25 608.4亿元;农产品生产价格指数的提升、单位面积产值的快速增加叠加上农作物播种面积的稳定增长,导致研究期间种植业增加值的明显上升;种植业增加值呈现“北进中移”的发展趋势,长江中下游区、黄淮海区、西南区等省域的种植业增加值明显增加。② 各因素对各省域种植业增加值的作用方向和作用强度呈现出一定的差异性,农产品价格指数的明显提升和单位面积产值的快速增加是大部分省域种植业增加值快速增长的主要推动力,而农作物播种面积的稳定增加也起到比较明显的正向促进作用;新疆和内蒙古农作物播种面积的正向效应明显,北京、上海和浙江农作物播种面积的负向效应明显;东部沿海省域和直辖市增加值率的负向效应比较明显。     

近300年来玉米种植制度的形成与地域差异

农作物种植制度是作物生理特征与生态环境等多重因素相互结合的产物,玉米作为外来作物进入中国境内,在同传统作物的竞争中,通过环境适应与文化认同,一方面形成以山区为优势的土地利用形式,另一方面则通过产量优势取代了谷子等作物的种植空间,加入到作物轮作系统中,并在空间上形成北方一年一熟制春玉米轮作区、北方两年三熟制夏玉米轮作区、南方丘陵山区玉米、杂粮轮作区。     

中老缅交界地区橡胶种植的时空格局及其地形因素分析

橡胶林地是东南亚地区主要的土地利用类型,动态监测橡胶种植并分析其时空变化规律,对于区域土地资源开发、生态环境保护以及维护边境安全稳定具有重要意义。本文基于遥感技术实地研究了中老缅交界地区1980-2010 年的橡胶林地分布格局及其时空变化规律,定量分析了橡胶林地的分布特征及其地形因素的影响与限制。结果表明:(1) 2010 年中老缅交界地区橡胶林地面积为60.14 万hm²,占土地面积的8.17%,是研究区最大的土地利用类型。就林地结构来看,橡胶成林(≥10 年) 与橡胶幼林(<10 年) 之比大体是5:7,近10 年来橡胶林地扩展迅速。(2) 1980-2010 年中老缅交界地区橡胶林地已由最初的7.05 万hm²增加到60.14 万hm²,扩展近9 倍,橡胶林地扩张显著。橡胶林地已呈现由集中至分散、由边境向国外,“以景洪为中心、北上南进、西拓东扩”的空间分布格局与地域扩展特征。(3) 中老缅交界地区橡胶种植受地形因素制约,橡胶林地4/5 以上集中在600~1000 m适宜区间,很少超过1200 m;近2/3 集中分布在8°~25°的坡地,极少或很少分布在超过35°的急陡坡;主要分布在南坡和东坡,北坡和西坡相对较少,橡胶种植强度也呈现相同规律。(4) 橡胶林地国别对比分析表明,中国境内橡胶林地在向高海拔、陡坡地扩展,老缅境内具有较大地形适宜空间,有利于橡胶种植的跨境发展。(5) 中老缅交界地区的橡胶种植必将由中国向老挝和缅甸跨境发展,老挝和缅甸境内,特别是近中国边境地区的橡胶林地持续扩张已是不可避免。     

Rubber plantation and its relationship with topographical factors in the border region of China, Laos and Myanmar

Rubber plantation is the major land use type in Southeast Asia. Monitoring the spa- tial-temporal pattern of rubber plantation is significant for regional land resource development, eco-environmental protection, and maintaining border security. With remote sensing tech- nologies, we analyzed the rubber distribution pattern and spatial-temporal dynamic; with GIS and a newly proposed index of Planted Intensity （PI）, we further quantified the impacts and limits of topographical factors on rubber plantation in the border region of China, Laos and Myanmar （BRCLM） between 1980 and 2010. The results showed that： （1） As the dominant land use type in this border region, the acreage of rubber plantation was 6014 km2 in 2010, accounting for 8.17% of the total area. Viewing from the rubber plantation structure, the ratio of mature- （〉10 year） and young rubber plantation （〈 10 year） was 5：7. （2） From 1980 to 2010, rubber plantation expanded significantly in BRCLM, from 705 km2 to 6014 km2, nearly nine times. The distribution characteristics of rubber plantation varied from concentrated toward dispersed, from border inside to outside, and expanded further in all directions with Jinghong City as the center. （3） Restricted by the topographical factors, more than 4/5 proportion of rubber plantation concentrated in the appropriate elevation gradients between 600 and 1000 m, rarely occurred in elevations beyond 1200 m in BRCLM. Nearly 2/3 of rubber plantation concentrated on slopes of 8~-25~, rarely distributed on slopes above 35~. Rubber plantation was primarily distributed in south and east aspects, relatively few in north and west aspects. Rubber planted intensity displayed the similar distribution trend. （4） Comparative studies of rubber plantation in different countries showed that there was a remarkable increase in area at higher elevations and steeper slopes in China, while there were large appropriate topog- raphical gradients for rubber plantation in Laos and Myanmar which benefited China for rubber trans-boundary expansion. （5） Rubber plantation in BRCLM will definitely expend cross borders of China to the territories of Laos and Myanmar, and the continuous expansion in the border region of China will be inevitable.     

基于Logit 模型的世界主要作物播种面积变化模拟

农作物播种面积动态变化因其重要性已经引起了国内外学者的广泛关注。从“人-地 关系”中人的角度出发, 利用多元Logit 模型初步建立了全球尺度的农作物播种面积变化模 拟系统, 分析研究了未来30 年内世界主要农作物播种面积变化的数量特征和空间格局。模型建立思路是: 作物播种面积变化是农户作物选择行为的直接结果, 而选择何种作物进行播种是由作物效用决定的。因此, 利用离散选择理论, 选择影响作物效用大小的主要解释变量建立效用函数, 动态模拟农户作物选择行为, 并得到这种选择行为所带来的农作物播种面积变 化的时空特征。模型建立后, 利用联合国粮农组织(FAO) 2001-2003 年统计数据和2001 年MODIS 全球土地覆盖数据产品对模型结果进行验证, 结果表明模型运行可靠, 和实际状况吻合较好, 可以应用于未来情景模拟分析。其后, 以5 年为步长, 模型对世界四大作物(水稻、玉米、小麦和大豆) 在2005-2035 年间的播种面积动态变化进行了模拟, 从全球作物总播种面 积变化差异、四大作物播种面积变化的区域差异和不同区域内四大作物播种面积变化差异等方面进行了分析研究, 结果表明: 不同作物播种面积变化的数量特征和空间格局是不相同的。 虽然目前模型还存在一些不确定性, 但仍然能够在一定程度上为理解现在和未来农业土地利用的复杂动态变化提供帮助, 模拟结果可为有关部门提供决策支持和信息服务。