南方水稻复种指数变化对国家粮食产能的影响及其政策启示（英文）

Changes in rice production in Southern China are crucial to national food security. This study employed Landsat images to map the distributions of paddy rice-cropping systems in Southern China in 1990 and 2015. The impact of rice multiple cropping index changes on grain production capacity was then evaluated. Three important results were obtained for the 1990 to 2015 study period. First, the multiple cropping index for rice decreased from 148.3% to 129.3%, and 253.16×10~4 ha of land area was converted from double-cropping to single-cropping rice, termed "double to single". The area with the most dramatic changes is in the Middle-Lower Yangtze Plain. The rice-cropping system distribution in Southern China showed a change from north to south with double-cropping rice shrinking and single-cropping rice expanding. Second, the "double to single" conversion led to a reduction of 6.1% and 2.6% in rice and grain production, respectively. Hunan and Jiangxi Provinces, located in the main rice producing areas, and Zhejiang, which has shown better economic development, exhibited large reductions in rice production due to the "double to single" conversion, all exceeding 13%. Third, the grain production capacity of converted "double to single" paddy fields is equivalent to that of 223.3 × 10~4 ha of newly reclaimed cultivated land, which is 54% of the total newly cultivated land reclaimed through the 2001–2015 land consolidation project. It is also 1.7 times the target goal for newly cultivated land in the national land consolidation plan for 2016–2020. Making full use of the converted "double to single" paddy fields can save 167.44 billion yuan in newly reclaimed cultivated land costs. Therefore, instead of pursuing low-quality new arable land, it is better to make full use of the existing high-quality arable land. Based on these results, the government should change the assessment method for cultivated land balance, and incorporate the sown area increased by improving the multiple cropping index into the cultivated land compensation indicator.     

1980–2011年中国农作物种植结构时空变化（英文）

Understanding the spatial and temporal variations of cropping systems is very important for agricultural policymaking and food security assessment,and can provide a basis for national policies regarding cropping systems adjustment and agricultural adaptation to climate change.With rapid development of society and the economy,China's cropping structure has profoundly changed since the reform and opening up in 1978,but there has been no systematic investigation of the pattern,process and characteristics of these changes.In view of this,a crop area database for China was acquired and compiled at the county level for the period 1980–2011,and linear regression and spatial analysis were employed to investigate the cropping structure type and cropping proportion changes at the national level.This research had three main findings:(1) China's cropping structure has undergone significant changes since 2002;the richness of cropping structure types has increased significantly and a diversified-type structure has gradually replaced the single types.The single-crop types—dominated by rice,wheat or maize—declined,affected by the combination of these three major food crops in mixed plantings and conversion of some of their planting area to other crops.(2) In the top 10 types,82.7% of the county-level cropping structure was rice,wheat,maize and their combinations in 1980;however,this proportion decreased to 50.7% in 2011,indicating an adjustment period of China's cropping structure.Spatial analysis showed that 63.8% of China's counties adjusted their cropping structure,with the general change toward reducing the main food types and increasing fruits and vegetables during 1980–2011.(3) At the national level,the grain-planting pattern dominated by rice shifted to coexistence of rice,wheat and maize during this period.There were significant decreasing trends for 47% of rice,61% of wheat and 29.6% of maize cropping counties.The pattern of maize cropping had the most significant change,with the maize proportion decreasing in the zone from northeastern to southwestern China during this period.Cities and their surroundings were hotspots for cropping structural adjustment.Urbanization has significantly changed cropping structure,with most of these regions showing rapid increases in the proportion of fruit and vegetables.Our research suggests that the policy of cropping structural adjustment needs to consider geographical characteristics and spatial planning of cropping systems.In this way,the future direction of cropping structural adjustment will be appropriate and scientifically based,such as where there is a need to maintain or increase rice and wheat cropping,increase soybean and decrease maize,and increase the supply of fruit and vegetables.     

改革开放以来中国农业政策效果的时空计量分析

Since reform and opening up, how much contribution has China’s implementation of new agricultural policy made to agricultural output? This paper is trying to establish an agricultural policy output econometric model for doing a quantitative analysis of China’s new agricultural policy. The results show that China’s agricultural policies on agricultural output have an average contribution rate of about 7% since 1978, which is consistent with the OECD’s basic forecast. There are obvious temporal and spatial differences. Generally speaking, we can divide the contribution of agricultural policy into three periods, which are the start-up phase from 1978 to 1991 (14 years), the stationary phase from 1992 to 2002 (11 years) and the rising phase from 2003 to 2008 (6 years). In space, the contribution of agricultural policy underwent a process from the all-low in the start-up phase, the gradual increase in the stationary phase to the all-high in the rising phase. Northern and western regions are more sensitive to policies. There are three major factors that can affect the contribution of regional agricultural policies, which are the process of national industrialization strategy, terrain and the level of local finance.     

Feasibility analysis of a double-cropping system for the efficient use of farmland on China's Loess Plateau

Cropping systems worldwide have been affected by the current trend in global warming and the optimization of cropping systems is an important area of research in the transition of agricultural land. The Loess Plateau is a typical ecologically fragile region with the most serious soil erosion in China. We carried out a field experiment in Yan’an city on the Loess Plateau to explore the effect of sowing date on crop growth and yield. We then analyzed the feasibility of a double-cropping system by ...     

2000–2012年中国黄淮海农业区多熟种植时空变化（英文）

Multiple cropping index(MCI) is the ratio of total sown area and cropland area in a region,which represents the regional time intensity of planting crops.Multiple cropping systems have effectively improved the utilization efficiency and production of cropland by increasing cropping frequency in one year.Meanwhile,it has also significantly altered biogeochemical cycles.Therefore,exploring the spatio-temporal dynamics of multiple cropping intensity is of great significance for ensuring food and ecological security.In this study,MCI of Huang-Huai-Hai agricultural region with intensive cropping practices was extracted based on a cropping intensity mapping algorithm using MODIS Enhanced Vegetation Index(EVI) time series at 500-m spatial resolution and 8-day time intervals.Then the physical characteristics and landscape pattern of MCI trends were analyzed from 2000–2012.Results showed that MCI in Huang-Huai-Hai agricultural region has increased from 152% to 156% in the 12 years.Topography is a primary factor in determining the spatial pattern dynamics of MCI,which is more stable in hilly area than in plain area.An increase from 158% to 164% of MCI occurred in plain area while there was almost no change in hilly area with single cropping.The most active region of MCI change was the intersection zone between the hilly area and plain area.In spatial patterns,landscape of multiple cropping systems tended to be homogenized reflected by a reduction in the degree of fragmentation and an increase in the degree of concentration of cropland with the same cropping system.     

中国南方调整水稻种植格局——一种水稻生产预先适应气候变化的选择(英文)

Rice planted in southern China accounts for 94% of the total in sown acreage and 88% of the total in production, which matters a lot to Chinese food security. However, due to the prolonged conflict between water availability and rice growth in spatial/temporal distribu-tion, rice production suffers from seasonal drought at acreage of 16%-22%, which compro-mises food production capacity and food security. Focusing on the spatial distribution of seasonal drought with rice and the practices to adapt to it, and based on an analysis of bal-anced water supply for and demand by rice at a growing season scale during 1981-2030, this paper assesses the changing seasonal drought in the process of rice production under the changing climate in the future, and identifies general rice re-cultivation options for climate change adaptation. Some conclusions can be drawn as follows. (1) Rice suggests a decline in seasonal drought, with early season rice (early rice hereafter) by 12,500 km2, middle season rice (middle rice) by 80,000 km2, and in particular late season rice (late rice) by 25,000 km2, which accounts for almost 20% of its cultivated acreage. It is indicated that due to climate change, seasonal drought in major rice producing areas tends to alleviate in general, late season rice in particular. (2) Future climate change brings about a significant impact on the spatial/temporal distribution of water resources in rice producing areas in China. Based on ’pre-designed’ adaptation actions for rice-re-cultivation, the rice cultivation pattern undergoes a significant alteration between 1981-2000 and 2001-2030. In eastern Guizhou and western Hunan, the pattern of single early plus single dry farming is changed into double cropping. In eastern Hunan, the pattern of dry cropping is changed into single early plus single dry farming. In northern Anhui, the pattern of dry farming cropping is changed into middle rice. All this is aimed at a potential adequate availability of water for rice production in the future. (3) Rice re-cultivation patterns developed in this paper help re-balance water demand and supply for rice growth using the spatial analysis tool to adapt rice growth to the changing water avail-ability from spatial perspective, and come up with rice producer-friendly re-cultivation options in response to climate change.     

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.     

Agricultural Climate Change and Wetland Agriculture Study under the Climate Change in the Sanjiang Plain

With linear curvefitting, Mann-kendall method and Yamamoto method, ≥10 ℃accumulated temperature and precipitation from May to September of 6 meteorological stations (Baoqing, fujin, Jiamusi, Hegang, Jixi and Hulin) from 1978 to 2007 were used to explore 30-year agricultural climate change and trend in the Sanjiang Plain. The results showed that ≥10 ℃ accumulated temperature of the 6 stations have risen by 141.0 ℃ to 287.4 ℃ when estimated by their significant linear trends (n=30, α=0.05) over the last 30 years (1978 to 2007). The rates of warming for the last 30 years range from 4.70 ℃per year to 9.58 ℃ per year. There are not significant linear trends on precipitation from May to September of the 6 stations over the last 30 years. The period of 1978 to 1998 in which ≥10 ℃ accumulated temperature is lower is consistent with that in which there is more precipitation from May to September, and warming and drying period has occurred in the Sanjiang Plain since 1999. Under the background of warming and drying agricultural climate, high yield cultivation of Phragmites australis and establishment of Phragmites australis-fish (crab) symbiosis ecosystem in natural mire are the ways for reasonable use of natural wetland. The area of paddy fields has been increasing from 7.25×104 ha in 1978 to 121.2×104 ha in 2006. It is proposed that paddy field range should not be expanded blindly toward the north in the Sanjiang Plain, and chilling injury forecast and prevention should be pay attention to. In the area that the chilling injury happens frequently, the rotation between rice and other crops should be implemented. Measures, which combine drainage, store and irrigation, should be taken instead of single drainage on comprehensive control of regional low and wet croplands to ensure controlling drought and flood.     

澜沧江流域农业灌溉需水的时空变化(英文)

Based on the data of eight meteorological stations from the 1950s to 2007, current cropping patterns, field water moisture management, we use the Mann-Kendall and the Re-scaled Range Analysis methods to research the changes of humidity and crop irrigation water requirements in the Lancang River Basin. The results show that the annual and dry season average temperatures significantly increased, and the dry season rainfall increased while wet season rainfall decreased. Evaportranspiration (ET0) increased during both dry and wet seasons at all stations except Dali, Jianchuan and Gengma, and the aridity-humidity index decreased at most of the stations. The turning points of weather factors, ET0, the arid-ity-humidity index, paddy irrigation requirements and total agricultural water requirements occurred from the 1960s to the 1990s. The spatial changing tendency of paddy irrigation quota increased with the increase of altitude and latitude, and the correlation coefficients are 0.513 and 0.610, respectively. The maximum value is observed in Weixi, while the minimum in Mengla.     

利用GIS和Dyna-CLUE模拟泰国东北部粮食作物保护区土地利用变化（英文）

Land use in the northeast region of Thailand has changed dramatically in the past two decades. These changes are mainly due to the government policies, which launched a scheme to promote rubber plantation during 2003–2013 targeting to solve the problem of poverty in the region. At least 50,000 ha of paddy fields were found to be converted to other land use types between 2002 and 2012. This study was conducted in Nong Khai and Bueng Kan province of northeast Thailand, where massive rubber plantation is going on prompting significant amount of land-use change, with the objective of investigating how land-use changes will affect on food availability in future. We analyzed land-use changes of the past and simulated future land uses using GIS and Landsat Thematic Mapper Data. The most obvious change was the decrease in paddy field and an increase in rubber plantation. This eventually leads to decreased paddy production affecting food supply of farm households. The land use projections for 2032 were done for three scenarios using Dyna-CLUE model. Unlike business as usual scenario, which will further decrease the paddy area, other scenarios with different land use policies if implemented will help protect paddy areas and thus achieving higher food production locally. The lack of implementation of proper spatial policies will lead to a further loss of paddy areas at macro level.The smallholder farmers may be highly vulnerable to land use-change and experience significant food crop losses, food insecurity and income loss when they change the land to rubber and there is market failure.     

Farmer-based Rice Cropping Systems in the Poyang Lake Region,China: Analysis of Characteristics and Policy Implications

This paper examines the spatial characteristics of farmer/household behaviors in regional rice cropping systems (RCS), and the results provide necessary information for developing strategies that will maintain regional food security. Through field study and statistical analysis based on 402 households questionnaires finished in 2014-2015 in the Poyang Lake Region (PLR) of China, we arrived at two main conclusions. First, single- and double cropping rice were found across the study area, but showed a general distribution trend, with double cropping rice in the southeast part (especially in Jinxian county) and single cropping rice in the northwest (particularly in De’an county). Second, the household decisions concerning RCS varied in different parts of the PLR, but double cropping was the dominant type, with about 63.57% of the respondent households in the PLR cultivating double cropping rice. However, the multiple-cropping index of paddy rice was only 1.55. About 3% of interviewed households had altered their RCS during this period. Based on these findings, the local governments should guide farmers’ paddy field cultivation behaviors by increasing the comparative efficiency of rice production, promoting appropriate scale operations and land conversion, as well as optimizing rice growing conditions to improve the multiple cropping index and enhance food provision. Finally, land-use efficiency and more sustainable use of land resources should be improved.     

南方水稻复种指数变化对国家粮食产能的影响及其政策启示

中国南方地区水稻生产的变化对国家粮食安全具有重要影响。本文利用Landsat数据提取1990-2015年南方地区水稻种植制度分布及变化,并分析其对粮食产能的影响。结果表明：① 1990-2015年,水稻复种指数从148.3%下降到129.3%,双季稻改种单季稻（“双改单”）损失的播种面积为253.16万hm²,区域上以长江中下游地区变化最为突出。南方地区水稻种植制度整体呈现由北向南“双退单进”的变化格局;② 1990-2015年,“双改单”导致全国水稻产量减少6.1%,粮食产量减少2.6%。水稻主产区湖南省和江西省以及经济发展较好的浙江省因“双改单”水稻减产幅度较大,均超过13%;③ 充分利用“双改单”稻田的粮食产能相当于新增耕地223.3万hm²,为2001-2015年通过土地整治项目新增耕地总量的54%,是2016-2020年全国新增耕地规划目标的1.7倍,可节省约1674.4亿元新增耕地开垦费用。因此,与其追求低质量的“新”耕地,不如充分利用已有的高质量“旧”耕地,政府应转变耕地占补平衡的考核方式,将因提高复种指数增加的播种面积纳入补充指标。     

鄱阳湖平原粮食主产区农户水稻熟制决策行为分析

中国南方粮食生产区水稻熟制受市场和农业政策等影响频繁波动,对保障区域粮食安全构成了一定挑战。以鄱阳湖平原粮食主产区为研究单元,基于问卷调查法于2014-2015年收集了19个县（区）共682例农户水稻熟制调查问卷资料,分析该区水稻熟制现状及农户熟制决策行为,并利用Logistic回归法分析农户水稻熟制变化因素及其影响程度。结果表明：① 研究区内60.4%的受调查农户只选择种双季稻,26.7%的受调查农户只选择种单季稻,10.2%的农户同时种植双季稻和单季稻。因此双季稻是鄱阳湖平原粮食主产区主要的水稻种植制度。然而,受调查双季稻农户中有5.4%因其低丘岗地田块缺水灌溉或低地田块易长期受渍涝影响而只种早稻或晚稻,而农户弃耕、转出全部土地及耕地他用的占比达3.7%。② 受调查农户双季稻种植比单季稻种植的纯收入高323.9元/亩,但产投比和利润率单季稻比双季稻每亩分别高出15.9%和115.9%;③ 收入、灌溉条件、劳动力、田块质量、田块距离等是影响农户水稻熟制决策的主要因素,其中收入和灌溉条件分别占水稻熟制变化驱动因素的36.6%和28.5%。     

基于MODIS的杭州湾南岸农业生态系统NDVI季节变化特征研究

NDVI是表征植物生长动态的重要指标,不同植物具有不同的NDVI变化曲线。植物生长过程中NDVI值逐渐增大。在生育期的某一阶段达到最大值后又逐渐减小。MODIS-NDVI数据因具有较高的时间分辨率。可用于农业生态系统NDVI变化研究。该文运用野外调查资料和2002年MODIS-NDVI 16d合成的23个时序的遥感数据。对杭州湾南岸农业生态系统不同种植制度的NDVI变化特征进行分析。结果表明,不同种植制度的NDVI曲线有其特定的变化规律。NDVI特征模型可用于农业生态系统种植制度分析,并为遥感估产提供基础数据。     

Spatiotemporal changes of cropping structure in China during 1980-2011

Understanding the spatial and temporal variations of cropping systems is very important for agricultural policymaking and food security assessment, and can provide a basis for national policies regarding cropping systems adjustment and agricultural adaptation to climate change. With rapid development of society and the economy, China’s cropping structure has profoundly changed since the reform and opening up in 1978, but there has been no systematic investigation of the pattern, process and characteristics of these changes. In view of this, a crop area database for China was acquired and compiled at the county level for the period 1980-2011, and linear regression and spatial analysis were employed to investigate the cropping structure type and cropping proportion changes at the national level. This research had three main findings: (1) China’s cropping structure has undergone significant changes since 2002; the richness of cropping structure types has increased significantly and a diversified-type structure has gradually replaced the single types. The single-crop types—dominated by rice, wheat or maize—declined, affected by the combination of these three major food crops in mixed plantings and conversion of some of their planting area to other crops. (2) In the top 10 types, 82.7% of the county-level cropping structure was rice, wheat, maize and their combinations in 1980; however, this proportion decreased to 50.7% in 2011, indicating an adjustment period of China’s cropping structure. Spatial analysis showed that 63.8% of China’s counties adjusted their cropping structure, with the general change toward reducing the main food types and increasing fruits and vegetables during 1980-2011. (3) At the national level, the grain-planting pattern dominated by rice shifted to coexistence of rice, wheat and maize during this period. There were significant decreasing trends for 47% of rice, 61% of wheat and 29.6% of maize cropping counties. The pattern of maize cropping had the most significant change, with the maize proportion decreasing in the zone from northeastern to southwestern China during this period. Cities and their surroundings were hotspots for cropping structural adjustment. Urbanization has significantly changed cropping structure, with most of these regions showing rapid increases in the proportion of fruit and vegetables. Our research suggests that the policy of cropping structural adjustment needs to consider geographical characteristics and spatial planning of cropping systems. In this way, the future direction of cropping structural adjustment will be appropriate and scientifically based, such as where there is a need to maintain or increase rice and wheat cropping, increase soybean and decrease maize, and increase the supply of fruit and vegetables.     

农田景观空间异质性分析及遥感监测最优尺度选择——以三江平原为例

农情遥感监测需要高时间分辨率的遥感数据,目前这些数据大都为中低空间分辨率影像。在这些尺度下,像元内部往往是异质的,从而影响农情参数反演精度。因此分析和表达农田景观空间异质性和最优尺度选择对遥感农情监测质量的提高具有重要的应用价值。选取建三江农垦区四种典型农田景观为研究点,Landsat/TM NDVI为实验数据,利用实验变异函数对四种景观类型的各向空间异质性进行了分析, 而后通过变异函数模型拟合,定量分析了各个研究点的整体空间异质性,并在此基础上进行了研究区遥感监测最优尺度选择。研究表明:(1) 基于实验变异函数的结构分析方法,可定性地认识空间异质性的大小和方向,进而挖掘出其背后的自然和人为驱动因素。(2) 对实验变异函数进行拟合分析,可定量地刻画不同景观格局各自的空间异质性特性。此外,基于变异函数对空间异质性的定量表达,讨论了利用积分变程A结合Nyquist-Shannon采样定理进行最优尺度选择的方法。     

河南省原阳县引黄灌区水稻田信息提取研究

水稻田是一种人工湿地.快速、准确地获取水稻的种植和生长信息,对于加强水稻田管理具有重要的实践意义.以河南省新乡市原阳县引黄灌区的水稻田为研究对象,采用随机森林算法,利用2020年8月26日和9月11日的Landsat 8 OLI影像数据,提取研究区的地表水分指数(land surface water index,LSW...     

湖南省地形因素对水稻生产的影响

作为一种人工生态系统,水稻的生产受自然条件和人为管理的共同影响。其中,地形因素不仅决定了水稻生长必须的光热等资源的再分配,而且还影响人类的农业管理活动。以中国水稻主产区中地形较为复杂的湖南省为研究对象,基于多种数据,从生态学的“格局—过程”思想出发,讨论了地形因素对水田分布、水稻生长过程及水稻产量的影响。研究发现,地形因素对水田分布的空间格局影响最为明显,对水稻生长过程影响次之,而对水稻产量影响较弱。在各地形因素中,高程对于水稻生产的影响最为突出。研究结果还反映出地形因素造成了湖南省水田分布和热量分配在北部平原地区的不匹配,政府部门应根据区域特征,因地制宜采取措施,提高该地区水稻生产效益。     

Paddy rice multiple cropping index changes in Southern China

Journal of Geographical Sciences - Changes in rice production in Southern China are crucial to national food security. This study employed Landsat images to map the distributions of paddy...     

Linking Spatial and Temporal Variation at Multiple Scales in a Heterogeneous Landscape*

Anthropogenic, ecological, and land‐surface processes interact in landscapes at multiple spatial and temporal scales to create characteristic patterns. The relationships between temporally and spatially varying processes and patterns are poorly understood because of the lack of spatiotemporal observations of real landscapes over significant stretches of time. We report a new method for observing joint spatiotemporal landscape variation over large areas by analyzing multitemporal Landsat data. We calculate the spatiotemporal variation of the Normalized Difference Vegetation Index (NDVI) in the area covered by one Landsat scene footprint in north central Florida, over spatial windows of 10⁴–10⁸ m² and time steps of two to sixteen years. The correlations, slopes, and intercepts of spatial versus temporal regressions in the real landscape all differ significantly from results obtained using a null model of a randomized landscape. Spatial variances calculated within windows of 10⁵–10⁷ m² had the strongest relationships with temporal variances (regressions with both larger and smaller windows had lower coefficients of determination), and the relationships were stronger with longer time steps. Slopes and y‐intercepts increased with window size and decreased with increased time step. The spatial and temporal scales at which NDVI signals are most strongly related may be the characteristic scales of the processes that most strongly determine landscape patterns. For example, the important time and space windows correspond with areas and timing of fires and tree plantation harvests. Observations of landscape dynamics will be most effective if conducted at the characteristic scales of the processes, and our approach may provide a tool for determining those scales.