共查询到20条相似文献，搜索用时 986 毫秒
1.
Paul Longley 《International journal of geographical information science》2013,27(7):1213-1214
With the rising oil prices, climate change, and the ever increasing burden of nutrition-related disease, food security is of growing research interest in academic disciplines spanning agronomy to epidemiology to urban planning. Some governments have developed progressive policies encouraging individuals to consume locally produced foods in order to support local economies, improve agricultural sustainability and community access to food, and to plan and prepare for adverse environmental impacts on food security. However, fundamental methods are lacking for conducting research on food security across these various disciplines. In this article, we first present a method to measure agricultural self-sufficiency, which we refer to as our self-sufficiency index (SSI) for the province of British Columbia, Canada. We then present a Bayesian autoregressive framework utilizing readily available agricultural data to develop predictive smoothing models for the SSI. We find that regional capital investment in agriculture and cropland acreage is the strong predictor of SSI. To accommodate spatial variability, we compare linear regression models with spatially correlated errors to less traditional spatially varying coefficient models, and find that the former class results in better model fit. The smoothed maps suggest that relatively strong self-sufficiency exists only in subset clusters in the Okanagan, Peace River, and lower mainland regions. In spite of policy to promote local food, the existing local agricultural system is insufficient to support a large-scale shift to local diets. Our approach to estimating neighborhood-based self-sufficiency with a predictive model can be extended for use in other regions where limited data are available to directly assess local agriculture and benefit from explicit consideration of spatial structure in the local food system. 相似文献
2.
干旱对作物产量影响研究进展与展望 总被引：1，自引：0，他引：1
粮食安全关乎人类生存和社会发展,是总体国家安全观的重要组成部分。本文首先梳理了作物产量影响因素及干旱对作物产量的影响过程,进而从基于田间控制实验、统计模型、作物生长机理模型以及遥感反演模型等4个方面系统回顾了干旱对全球主要作物产量影响评估的最新进展,揭示出当前研究呈现出由单灾种向多灾种、由单目标向多目标、由统计模型向综合模型转变的特征。文献计量分析表明,1990—2020年干旱对作物产量影响研究发文量呈指数增长,且研究主题经历了由传统的作物水分胁迫到作物受旱影响与适应综合研究的转变过程,体现出研究视角的不断深化和综合。在学科分布上,农学、植物学和环境科学是研究干旱对作物产量影响的主要学科,建议应加强地理学多要素多尺度的系统性思维在粮食和水资源耦合系统研究中的应用。最后,在分析现有问题和挑战的基础上,将未来应关注的重要议题归纳为以下4个方面,即构建干旱对作物产量影响的多源信息数据库、阐明干旱对作物产量影响的关键过程及机理、发展耦合宏观与微观过程作物生长机理模型和搭建作物产量与粮食安全综合监测平台系统,旨在通过提高干旱对作物产量影响的监测预警和科学管控,实现农业可持续发展和全球粮食安全。 相似文献
3.
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。 相似文献
4.
西北地区农业旱灾与预测研究 总被引：17，自引：4，他引：13
西北地区干旱灾害在中国乃至世界上具有代表性,常常对农业生产、社会经济和人民生活带来巨大威胁。利用西北五省区(陕西、甘肃、宁夏、青海、新疆)1951～2000年的50年农业旱灾面积统计资料,分析了农业旱灾的时空强度变化。表明西北地区农业旱灾有增加趋势,以20世纪90年代增加最明显。利用西北地区均匀分布的40个站点50年的降水和气温资料,采用变换的Z指数法,探讨了干旱强度和地表径流量的时间变化与西北地区农业旱害的关系。表明降水量的减少及河川径流枯期与农业旱灾面积负相关关系密切。应用波谱分析与逐步自回归方法,分别建立了西北地区干旱指数的拟合回归预测模型,农业旱灾面积、成灾面积和绝收面积预测模型,并对西北地区干旱灾害的趋势进行了预测。表明西北地区干旱灾害在21世纪前十年有所减缓。经检验,模型预测效果良好,根据预测结果可以采取有针对性的减灾措施,减少西北地区农业灾害损失。 相似文献
5.
极端降水在全球范围内呈现广泛增强的趋势,对农业生态系统的影响不容忽视。水稻作为重要的粮食作物,其产量的年际波动受到极端降水的影响,然而其响应机理和时空敏感性尚未厘清。论文总结了极端降水在水稻主产区的时空格局及对产量的影响程度,梳理了极端降水对水稻产量的生理、化学和物理过程的影响机制,对比分析了多个主流方法(统计模型和作物过程模型)的输入数据和应用上的优缺点。结果表明,极端降水增加1%导致水稻减产0.02%~0.5%,主要通过增加养分流失和造成淹水胁迫等途径。然而当前研究仍难以明确水稻产量如何响应于极端降水的不同特征值(强度、频次、持续时间等)及其敏感性的时空差异,尚未完善极端降水对水稻各产量组成的影响机理,同时缺乏作物模型与统计模型等相结合的研究方法,造成水稻产量预测的不确定性。建议未来相关研究应加强田间观测、控制性实验与模型改进,定量解析极端降水对产量的影响机理,促进模型—数据融合,提高数据精度以更好地模拟极端降水事件下的水稻产量,为优化当前稻作系统和建立气候智能型农业奠定理论基础。 相似文献
6.
干旱是农作物生长发育的主要环境胁迫因子,也是制约农业丰产丰收的关键自然要素。农业干旱监测通常基于气象站点观测数据,这在一定程度上难以反映区域尺度的农业干旱状况。以甘肃省为研究区,基于MODIS、TRMM、ESA CCI等遥感数据产品和气象站点数据,利用随机森林回归模型构建综合气象干旱指数（CMDI）,并对甘肃省2011—2019年农作物生长季（4—9月）旱情时空格局及变化规律进行分析。结果表明：（1）CMDI与实测值的决定系数（R2）在各月均高于0.634,且与标准化降水蒸散发指数（SPEI）在空间上具有一定的相关性,表明该指数可反映农业干旱的发生发展过程。（2）甘肃省农业干旱呈现明显的地域分异规律,干旱程度由东南向西北逐渐加重,其中河西地区多为特旱区和重旱区,陇中地区为重（中）旱区,陇南、陇东、甘南地区为干旱-无旱波动变化区。（3）2011—2019年甘肃省农业干旱在年、月尺度上均呈现较大的波动趋势,其中2012年干旱程度最轻,2017年则最为严重;甘肃省大部分地区在4月和6月,陇东、陇南地区分别在5月和9月以及甘南地区4—9月农业旱情有所减轻外,其余地区在农作物生长季的旱情呈加重趋... 相似文献
7.
Philip Antwi-Agyei Evan D.G. Fraser Andrew J. DougillLindsay C. Stringer Elisabeth Simelton 《Applied geography (Sevenoaks, England)》2012,32(2):324-334
This study evaluates new multi-scale, multi-indicator methods for assessing the vulnerability of crop production to drought at a national and regional scale. It does this by identifying differences across and within ten regions of Ghana, a country that faces many climate and crop production challenges typical of sub-Saharan Africa. In particular, we illustrate how a quantitative national and regional study is a critical first step in assessing differences in the drought sensitivity of food production systems and show how such an assessment enables the formulation of more targeted district and community level research that can explore the drivers of vulnerability and change on a local-scale. Finally, we propose methodological steps that can improve drought sensitivity and vulnerability assessments in dynamic dryland farming systems where there are multiple drivers of change and thresholds of risk that vary in both space and time. Results show that the vulnerability of crop production to drought in Ghana has discernible geographical and socioeconomic patterns, with the Northern, Upper West and Upper East regions being most vulnerable. Partly, this is because these regions have the lowest adaptive capacity due to low socioeconomic development and have economies based on rain-fed agriculture. Within these regions we find considerable differences between districts that can be explained only partly by socioeconomic variables with further community and household-scale research required to explain the causes of differences in vulnerability status. Our results highlight that national and regional scale multi-indicator vulnerability assessments are a vital (and often ignored) first step in assessing vulnerability across a large area. These inputs can guide both local-level research and also demonstrate the need for region-specific policies to reduce vulnerability and to enhance drought preparedness within dryland farming communities. 相似文献
8.
黄淮海平原雨养条件下冬小麦水分胁迫分析 总被引：5，自引：1，他引：4
雨养条件下的水分胁迫分析能够反映当地气候土壤条件下作物生长的水分环境对农作物生长的影响,可为农业干旱管理及灌溉策略的实施提供依据,减少农业干旱的发生。本文在阐述EPIC(Environmental Policy Integrated Climate Model)作物生长模型水分胁迫计算过程的基础上,模拟黄淮海平原冬小麦在雨养条件下的生长过程,分析水分胁迫现象的时空分异。结果发现,研究区内自然降雨远不能满足冬小麦的正常生长,从水分胁迫现象发生时间上讲,雨养条件下在冬小麦生长期后段(5月中旬以后)水分胁迫现象较为严重,以5月下旬最为严重,重度水分胁迫发生频率高达48.2%;从区域分布上分析,冀鲁豫低洼平原区和山东丘陵农林区水分胁迫现象在整个研究时间段上均较为突出。 相似文献
9.
农业干旱监测研究进展与展望 总被引：20，自引：1，他引：19
本文全面分析了农业干旱的概念内涵及其与其他干旱类型之间的关系,进而从基于站点监测和基于遥感监测两个方面,系统梳理了国内外农业干旱监测的近今进展,对比了不同干旱监测指标的适用范围和局限性;同时,通过文献统计和重要文献引用揭示了国内外农业干旱监测研究的发展历程和最新进展,即农业干旱监测指标从传统的单一气象监测指标逐渐向气象与遥感相结合的综合监测指标转变。最后,在分析农业干旱监测现有挑战和困境的基础上,将农业干旱监测未来发展趋向归纳为5点展望,即进一步明晰农业干旱发生机理和受旱过程、识别农业干旱影响因素及其相互作用关系、构建多时空尺度农业干旱监测模型、耦合农业干旱定性表征与定量评估模型以及提高农业干旱监测模型中遥感数据的应用水平。 相似文献
10.
Zhenhuan Liu Zhengguo Li Pengqin Tang Zhipeng Li Wenbin Wu Peng Yang Liangzhi You Huajun Tang 《地理学报(英文版)》2013,23(6):1005-1018
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. 相似文献
11.
GAO Jiangbo LIU Lulu GUO Linghui SUN Dongqi LIU Wanlu HOU Wenjuan WU Shaohong 《地理学报(英文版)》2023,33(1):37-58
The black soil region of northeast China is a vital food base and is one of the most sensitive regions to climate change in China. However, the characteristics of the crop phenological response and the integrated impact of climate and phenological changes on agricultural productivity in the region under the background of climate change are not clear. The future agricultural risk assessment has been insufficiently quantified and the existing risk level formulation lacks a sound basis. Based on remote sensing products, climate data, and model simulations, this study integrated a logistic function fitting curvature derivation, multiple linear regression, and scenario simulation to investigate crop phenology dynamics and their climate response characteristics in the black soil region. Additionally, the compound effects of climate and phenology changes on agricultural production and possible future risks were identified. The key results were as follows: (1) From 2000 to 2017, 29.76% of the black soil region of northeast China experienced a significant delay in the start of the growing season (SOS) and 16.71% of the total area displayed a trend for the end of the growing season (EOS) to arrive earlier. The time lagged effects of the SOS in terms of the crop response to climatic factors were site and climatic parameter dependent. The influence of temperature was widespread and its effect had a longer lag time in general; (2) Both climatic and phenological changes have had a significant effect on the inter-annual variability of crop production, and the predictive ability of both increased by 70.23%, while the predictive area expanded by 85.04%, as compared to that of climate change in the same period of the growing season; (3) Under the RCP8.5 scenario, there was a risk that the future crop yield would decrease in the north and increase in the south, and the risk area was constantly expanding. With a 2.0℃ rise in global temperature, the crop yield of the southern Songnen black soil sub-region would reduce by almost 10%. This finding will improve our understanding of the mechanisms underlying climate change and vegetation productivity dynamics, and is also helpful in the promotion of the risk management of agrometeorological disasters. 相似文献
12.
以农业干旱发生时所引起的若干地表特征变化为依坦,分别从土壤水分、植被水分、冠层温度和作物形态4方面,对现有主要农业干旱遥感监测模型进行归纳总结,分析了各种模型的优缺点,以及各自的适用范围。其中土壤水分变化类指数比较适宜于农业旱情预警及土壤干旱型农业旱情的监测;冠层温度变化类指数不仅适宜于农业旱情预警,更适宜于农业旱情监测;作物形态及绿度变化和植被水分变化类指数,较适宜于农业旱灾的预警以及灾后评估。 相似文献
13.
Simulating agricultural drought periods based on daily rainfall and crop water consumption 总被引：1，自引：0，他引：1
Even though drought is difficult to define precisely, rainfall is the most widely used indicator of drought. This paper presents a methodology on modeling of the agricultural drought duration. For this purpose, study area was divided into four hydrologic homogeneous sections as W, CN, CS and E. To constitute the monthly time series of each section, the number of days in each month in which daily rainfall was less than the water consumption of the critical crop was assumed to be drought periods. Then, constituted monthly time series of drought durations of each hydrologic homogeneous section was simulated using ARIMA model. No linear trend was observed for the time series except that of the CS section. In general, the predicted data from the selected best models for the time series of each section represents the actual data of that section. 相似文献
14.
基于Meta-Gaussian模型的中国农业干旱预测研究 总被引：1，自引：1，他引：0
在全球气候变化背景下,干旱愈加频发,有效且可靠的农业干旱预测对于保障粮食安全和水资源安全具有重要意义。以标准化降水指数（SPI）和联合标准化土壤湿度指数（JSSI）分别表征气象干旱和农业干旱,以前期的气象干旱和农业干旱指数作为预测因子,在1~3个月预见期下基于Meta-Gaussian（MG）模型对中国1961—2015年6—8月的农业干旱进行预测,并采用Brier Skill Score（BSS）和纳什效率系数（NSE）评价MG模型的预测性能。结果表明：① 将1个月、3个月、6个月、9个月和12个月时间尺度的标准化土壤湿度指数（SSI）结合起来得到的JSSI能够对中国农业干旱的综合状况进行客观评价。② 以中国2010年和2014年遭受严重的干旱事件为例,预见期为1~3个月时,除新疆南部、青海西部以及内蒙古西部等沙漠地区外,MG模型对6—8月农业干旱预测结果的分布范围与实际干旱的分布区域较吻合,预见期越短,吻合越好。③ 预见期为1个月时,6—8月BSS ≥ 0.5的面积比例分别为0.714、0.642和0.640,NSE ≥ 0.5的面积比例分别为0.903、0.829和0.837,表明MG模型能够对中国大部分区域的农业干旱作出可靠的预测。本文结果可为中国农业干旱的监测、预警及干旱决策提供科学指导。 相似文献
15.
Peter Kimosop 《Singapore journal of tropical geography》2019,40(2):239-256
The Kerio Valley basin in Kenya has undergone several periods of drought, yet drought patterns in the region are not well understood due to limited climatic data. Drought events in the region have resulted in crop failure and livestock deaths, exacerbating food shortages. In this study, the Standardized Precipitation Evapotranspiration Index (SPEI), a multi‐scalar drought index was used to examine the onset, duration, severity, intensity, and frequency of agricultural and hydrological drought in the region. The gridded 0.5° × 0.5° climatic datasets from Climatic Research Unit for the period 1960?2016 was used for analysis. Temporal evolutions of SPEI at 6‐ and 12‐month lags were subsequently used to evaluate agricultural and hydrological drought, respectively. Additionally, the Mann‐Kendall trend test was used to test for trends in the time series. Results from the analysis show that: 1) droughts are becoming more frequent in the region, 2) drought intensities in the arid and semi‐arid lands have weakened, 3) regions west of the Kerio River have recently recorded a wetting trend, and 4) the southern and central regions of the basin are drought‐prone. Understanding the spatial and temporal patterns of drought in the basin can assist in drought preparation and mitigation planning. 相似文献
16.
提高西北旱作农业干旱监测准确性和时效性,对农业生产防灾减灾有重要意义。利用甘肃省3个农业气象观测站长期土壤水分和冬小麦生育状况观测资料、1971—2016年43个冬小麦种植县气象观测资料及产量资料,基于冬小麦播前底墒和生育期水分盈亏量修订了作物水分盈亏指数,并确定了干旱等级指标,改进后作物水分盈亏指数与土壤贮水和冬小麦减产率高度相关,能更准确的反映甘肃省冬小麦干旱实况,并利用ArcGIS分析了近46 a甘肃省冬小麦不同生育期、不同等级干旱发生频率的时空分布特征。结果表明：甘肃省冬小麦从播种至开花期随着发育期推移,呈现干旱频率增加、范围扩大的趋势,多以中旱居多,其中拔节—开花期发生面积最大,陇中、庆阳市北部、平凉市西部、天水市西部、陇南市南部干旱出现频率较高;开花—成熟期随着降水量增加干旱发生频率减少、程度减轻。 相似文献
17.
业务化农业干旱监测系统是农业干旱监测和预测以及农业风险评价和防范的有力工具,为了更好地促进农业干旱业务化监测的发展,系统回顾了基于气象变量、土壤湿度、植被状态和多变量等4类常用干旱指数,详细分析了美国、中国、欧洲和联合国粮食及农业组织等业务化农业干旱监测系统的特征,讨论了业务化农业干旱监测系统中存在的问题：如数据的质量及融合不稳定、综合干旱指数的构建不确定、监测的时间分辨率有待提高、缺乏考虑水文条件以及作物的生长过程等影响的问题。展望了未来农业干旱业务化监测,应从利用多源数据监测干旱、构建综合指标时需考虑区域时空差异及不同指标间的累积性和滞后性、加强机器及深度学习在综合指标构建中的作用、发展日时间尺度监测干旱以应对骤旱事件的发生、强化作物生长过程模型和先进的技术手段在干旱监测中的作用等方面深入发展。 相似文献
18.
中原腹地气候变化对冬小麦产量的影响——以商丘地区为例 总被引：7，自引：2，他引：5
为探明气候变化对商丘地区冬小麦产量的影响,根据1991～2010商丘市气候资料和小麦产量资料,利用数学统计与Thornthwaite Memoriae模型,结合未来气候预测结果定量分析了气候变化对冬小麦产量的影响。结果表明,冬小麦产量整体上呈波动上升趋势;主成分分析表明,气温、降水量、蒸发量与极端温度为影响冬小麦产量的主要气候因子,蒸发量过大及极端低温对冬小麦生产不利。商丘地区"暖湿型"气候有利于冬小麦生产力的提高,"冷干型"气候对冬小麦生产最为不利;未来几十年内气候可能将向"暖湿型"变化,对商丘地区粮食作物产量的提升较为有利。 相似文献
19.
旨在模拟预测中国钾肥需求,为钾肥市场参与者和决策者提供基本的数据和理论支持。运用主成份分析法和多元回归计量经济模型模拟我国钾肥需求。首先,运用主成份分析法对钾肥需求影响因子进行降维处理;其次,采用多元统计非线性回归计量经济学模型模拟钾肥需求。结果表明:(1)钾肥需求与人均耕地、受灾面积、钾肥价格呈负相关关系;(2)钾肥需求与耕地、粮食用地、农产品价格存正相关关系;(3)钾肥需求预测可由较易得的人均耕地、耕地、粮食用地、受灾面积、农产品价格和钾肥价格数据代入模型模拟获得,且模拟数据与现实数据吻合较好;(4)此方法可较广泛运用,不需大量的野外试验和较大的工作量,且无空间跨度差异;(5)政府行为对钾肥需求有着极大的影响作用,政府应发挥其积极性,制定出一套有序的制度安排,以弥补市场本身潜在的问题,引导市场机制不断完善。 相似文献
20.
Xianfeng Liu Xiufang Zhu Yaozhong Pan Shuangshuang Li Yanxu Liu Yuqi Ma 《地理学报(英文版)》2016,26(6):750-767
In this paper, we compared the concept of agricultural drought and its relationship with other types of droughts and reviewed the progress of research on agricultural drought monitoring indices on the basis of station data and remote sensing. Applicability and limitations of different drought monitoring indices were also compared. Meanwhile, development history and the latest progress in agricultural drought monitoring were evaluated through statistics and document comparison, suggesting a transformation in agricultural drought monitoring from traditional single meteorological monitoring indices to meteorology and remote sensing-integrated monitoring indices. Finally, an analysis of current challenges in agricultural drought monitoring revealed future research prospects for agricultural drought monitoring, such as investigating the mechanism underlying agricultural drought, identifying factors that influence agricultural drought, developing multi-spatiotemporal scales models for agricultural drought monitoring, coupling qualitative and quantitative agricultural drought evaluation models, and improving the application levels of remote sensing data in agricultural drought monitoring. 相似文献