农业结构调整对全国粮食安全的影响分析--以粮食主产区为例

基于粮食主产区农业发展及其结构调整中面临的问题分析，指出近5年来导致我国粮食产量持续下降的主要原因在于农业结构调整。大规模的“压粮扩经”趋势若不能有效控制，必将对国家粮食安全带来冲击。对2005-2010年我国粮食需求及粮食主产区占全国粮食产量比重进行测算．提出不同粮食自给率下国家粮食安全对粮食主产区粮食生产的目标要求。粮食主产区具有满足国家粮食安全产量需要的生产潜力。     

中国粮食主产区利益补偿机制的构建与完善

中国粮食主产区建设作为一种具有外部效应的经济活动,不仅能带来经济收益,更是为国家粮食安全和全社会的稳定带来了巨大的社会效益.本文简要阐述了建立粮食主产区利益补偿机制的导向意义,运用对比分析法对粮食主产区的现状做了剖析.结果表明:我国粮食主产区建设随着国内外市场环境变化、各种矛盾约束加剧,依然面临诸多困境.如:二元结构矛盾突出、收入差距较大、农业基础设施建设滞后、粮食生产能力差异明显和发展粮食生产的包袱沉重等.我国粮食主产区建设要突破困境,必须在借鉴经济外部性理论,特别是实现外部效应内部化的公共政策机制的基础上,构建与完善粮食生产区利益补偿机制.其中,包括健全与完善国家粮食风险基金制度、粮食安全基金制度、种粮直接补贴政策、政府财政投入机制和金融支持机制度.构建与完善粮食主产区利益补偿机制是调动粮食主产区发展粮食生产的积极性,确保国家粮食安全的必要步骤和保障措施.     

基于三螺旋模型的国家粮食安全保障战略——以河南省为例

建立三螺旋粮食安全模型,对促进主产区粮食生产和保障国家粮食安全具有重要意义。结合粮食生产情况,利用统计数据,对粮食生产过程中的突出问题、时序动态和空间变化进行分析。随着粮食产量的增长,区域发展和农民收入差距拉大,土地高产出(粮食单产)与资源低效率并存,粮食生产成本的增加与粮食价格不能同步提高,出现粮食主产区财政收入和农民纯收入的"双低"现象,成为影响粮食安全的障碍因素。在此基础上,建立了粮食安全三螺旋模型,提出了保障国家粮食安全的政策建议。即在保障途径上,要实现中央政府、地方政府和农民农户目标的协调耦合;在策略行为上,粮食安全利益相关者之间的行为适度,利益均衡,互让互动,共生共长。充分发挥中央政府主导性、地方政府主动性和农民农户主体性,促进粮食综合生产能力提高、粮食产业能力提速和农民发展能力提升的良性循环,探索一条粮食产量与农民收入同步提高、主产区与主销区利益协调和不以牺牲粮食主产区生态和环境为代价的粮食生产持续稳定和谐发展之路。     

湖北省粮食生产的时空特征演变研究——基于耕地因素分解的视角

"藏粮于地"是新时期保障我国粮食安全的重要战略。分析湖北省粮食生产的时空演变特征,运用LMDI方法对影响粮食产量的耕地利用因素进行分解。结果表明:湖北粮食生产正处于稳定增长时期,但其周期性波动特征并未改变,粮食产量大幅波动的可能性仍然存在;湖北省粮食生产具有明显的中间高,两边低的区位特征;单产提高与复种指数上升是粮食增产的主要因素,种植业结构调整与耕地资源减少导致了粮食减产;由于自然环境与社会经济发展差异,不同区域种植业结构调整的程度与方向、耕地资源的利用方式都不相同。加强耕地资源保护,确保耕地数量不减少,质量不降低;调整耕地利用方式,合理安排耕作制度,优化种植业结构和区域布局;推进农业科技创新,培养新型职业农民,建立稳定的粮食生产队伍是实施"藏粮于地,藏粮于技"战略的有效途径。     

澜沧江上游高山峡谷区粮食安全状况及其变化特征分析——以德钦县为例

本文利用德钦县1978-2013年农业经济统计资料,采用主成分分析法(SPSS)分析了德钦县粮食安全现状及其变化特征,并揭示其主要驱动因子。研究结果表明:1德钦县粮食安全变化可划分为4个阶段,1978-1986年贫困向温饱过渡阶段、1987-1998年温饱向小康过渡阶段、1999-2005年小康向温饱过渡阶段和2006-2013年温饱向小康过渡阶段;2经济因素是影响粮食安全变化的主驱动力,使粮食安全由自给自足向以非粮收入为主导的状态转变;3粮食产量是粮食安全变化的另一主要驱动因子,直接影响人均有粮;4国家和云南省农业和林业等相关政策是影响粮食安全变化的重要驱动力,控制着种植结构、收入结构的发展变化趋势,促进农村劳务结构的调整。     

基于敏感度分析的江苏省粮食生产与耕地数量变化动态响应研究

江苏省作为我国重要的粮食生产基地,其耕地资源变化不仅影响区域的可持续发展,更关系国家的粮食安全。以江苏省55个县域为研究单元,结合数理统计和GIS空间分析,研究2000～2015年江苏省耕地与粮食生产的时空演变及粮食生产对耕地资源变化的敏感程度。结果表明:(1)江苏省耕地总体呈减少趋势,其中耕地相对稀疏区主要分布在苏锡常地区,而集聚区主要分布在苏北;粮食生产的空间格局与耕地分布基本一致,但总量呈增加趋势,2015年江苏省粮食产量达到3561×10~4 t,为2000年的1.15倍。(2)耕地重心与粮食产量重心的移动方位大致相同,均表现为向北偏西方向移动。(3)对比2000～2009年和2009～2015年两个时期,江苏省粮食产量对耕地资源变化的敏感性逐渐减弱。随着农业技术的发展,区域粮食生产对耕地面积的依赖程度逐渐降低,保护耕地与保障粮食安全亟需因地制宜,针对不同敏感性地区合理布局粮食生产。     

气候变化对中国不同粮食产区粮食安全的影响

随着全球气候变暖趋势的逐渐加剧,气候变化对粮食安全的影响引发社会各界广泛关注。文章基于1990—2020年31个省份的面板数据,在剖析气候变化与粮食安全关系的基础上,分析气候变化与粮食安全发展趋势,从粮食可用性、可获得性、可利用性、稳定性4个维度构建粮食安全指标体系,利用极差标准化法、变异系数赋权法、雷达图面积模型计算法测算粮食安全指数,实证验证气候变化对粮食安全的影响机制。研究发现：(1)积温和降水两大气候因子皆对粮食安全具有抑制作用。积温在1%的显著性水平上对粮食安全具有负向影响,降水在5%的显著性水平上对粮食安全产生不利影响。(2)农业技术的调节作用主要体现在其削弱了积温对粮食安全的抑制作用,但对降水影响粮食安全的调节效果并不明显。(3)分区域看,气候变化对粮食产销平衡区粮食安全的负向影响最大,对粮食主产区和主销区粮食安全的抑制作用不明显;农业技术在粮食主产区发挥的调节作用最强,在粮食主销区和产销平衡区发挥的调节作用不明显。为保障粮食安全,应强化应对气候变化的能力,逐步完善粮食储备管理机制,践行“藏粮于技”的战略方针,因地制宜调整粮食耕作制度和种植结构,培育优良作物品种,推进现代...     

1990～2015年长江流域县域粮食生产与粮食安全时空格局演变及影响因素分析

长江流域粮食生产与经济发展在全国均占据重要地位,研究近25年长江流域粮食生产与粮食安全时空格局演变及影响因素,可为我国粮食安全及流域可持续发展提供科学依据。基于1990、1995、2000、2005、2010和2015年长江流域县域粮食产量、户籍人口数据、农业化肥使用量和粮食播种面积（740个区县）,运用粮食变化指数、探索性空间数据分析（ESDA）、重心转移模型和空间误差模型(SEM)研究其时空格局演变特征及影响因素。研究结果表明：（1）1990～2015年长江流域粮食产量总体呈增长趋势,东西差异显著,年均增长率为0.5%,上中下游依次为0.6%、0.8%和 -0.7%;上游为劣势区,中游为优势增长区,下游为减弱区。（2）粮食产量冷点聚类一直分布在上游地区,聚类格局在2000年左右由西南边界的“L”型转变为西北倒“L”型;下游江淮地区与太湖平原的热点集聚在2000年后消失,且长期处于减产状态;人均粮食占有量与粮食产量时空格局演变呈较高的空间相似性,2000年为流域粮食生产与粮食安全格局发生变化的转折点。（3）1990～2015年长江流域一般余粮县和重要余粮县重心呈现出“南下西移”态势,缺粮县和供需紧平衡县重心发生了“从南向北、从西向东”迁移变化。（4）粮食播种面积和农业化肥施用量对粮食生产均具显著性正向效益。     

太湖流域粮食生产对耕地利用变化动态响应分析及预测

认识耕地利用与粮食生产的耦合作用规律是确保粮食安全和可持续发展的基础。基于模型模拟、GIS和多目标情景模拟等方法,在定量分析粮食生产对耕地利用变化动态响应基础上,分析流域粮食生产变化的关键驱动要素及粮食增产潜力,为流域耕地利用动态调控和粮食安全问题解决提供参考。结果表明:(1)1985～2015年流域耕地利用与粮食生产变化空间集聚性显著,耕地量变、耕地利用结构和方式变化幅度分别为39.2%、23.6%和19.3%,上述变化导致粮食减产44.1%;(2)1985～2015年耕地量变对流域粮食减产贡献率为50.7%,耕地利用方式变化和耕地量变则分别以43.4%和76.3%的贡献率成为前后15年粮食减产的主要驱动因素。集聚在流域北部56.8%的区域受耕地量变影响显著;太湖东南24.3%的区域和杭州-桐乡-嘉善一线等18.9%的区域分别受耕地利用方式和结构变化影响较大。随时间变化,耕地量变影响加剧,粮食减幅增加;(3)未来耕地数量持续减少,粮食安全压力较大,低-中-高方案变动下耕地量变影响范围缩小53.5%,耕地利用方式和结构影响区分别增加了2倍和1.25倍,粮食增产区由5.4%增加到54.1%。不同区域粮食生产对耕地利用变化响应的时空差异显著,未来响应变化敏感区将是流域粮食增产潜力区和耕地利用关键调控区。     

江苏省粮食安全问题及其对策

粮食安全是事关国家和地区社会稳定的重大问题。粮食安全不仅涉及粮食的数量，而且涉及粮食的质量，此外，粮食生产不应对环境造成负面影响。首先论述了研究粮食安全问题应遵循的原则，即系统原则，市场原则，高效和合理利用原则，宏观调控原则，以及层次性原则。然后，在简要回顾建国后江苏省粮食生产的历史之后，详细分析了近年来江苏省在粮食安全方面存在的主要问题，如粮食作物播种面积和总产量逐年减少；耕作粗放和农田环境污染问题日趋严重；农业生产结构调整面临挑战。为确保实现江苏省粮食安全的目标，要以“两种资源、两个市场”思想为指导，立足国内、省内，处理好各方面的关系；树立产业结构多元化思路，建立新型的农业产业体系；加强宏观调控力度，改善农业生产的软环境；大力发展特色农业和定单农业，提高农产品的市场竞争力和抵御国内外市场风险的能力；大力发展农业科技，为粮食生产在数量和质量上上新台阶提供支撑。     

Ethnosciences––A step towards the integration of scientific and indigenous forms of knowledge in the management of natural resources for the future

Integration of indigenous knowledge and ethnoscientific approaches into contemporary frameworks for conservation and sustainable management of natural resources will become increasingly important in policies on an international and national level, both in countries that are industrialised and those that have a developing status. We set the scene on how this can be done by exploring the key conditions and dimensions of a dialogue between ȁ8ontologiesȁ9 and the roles, which ethnosciences could play in this process. First, the roles of ethnosciences in the context of sustainable development were analysed, placing emphasis on the implications arising when western sciences aspire to relate to indigenous forms of␣knowledge. Secondly, the contributions of ethnosciences to such an ȁ8inter- ontological dialogueȁ9 were explored, based on an ethnoecological study of the encounter of sciences and indigenous knowledge in the Andes of Bolivia, and reviewed experiences from mangrove systems in Kenya, India and Sri Lanka, and from case-studies in other ecosystems world-wide, incl. Australia, Burkina Faso, Ecuador, Ethiopia, Guatemala, Indonesia, Nepal, Niger, Philippines, Senegal, South-Africa and Tanzania.     

Paradoxical ozone associations could be due to methyl nitrite from combustion of methyl ethers or esters in engine fuels

We review studies of the effects of low ambient ozone concentrations on morbidity that found a negative coefficient for ozone concentration. We call this a Paradoxical Ozone Association (POA). All studies were in regions with methyl ether in gasoline. All but one study carefully controlled for the effects of other criterion pollutants, so the phenomenon cannot be attributed to them. One was in southern California in mid-summer when ozone levels are highest. Because ozone is created by sunlight, the most plausible explanation for a POA would be an ambient pollutant that is rapidly destroyed by sunlight, such as methyl nitrite (MN). A previously published model of engine exhaust chemistry suggested methyl ether in the fuel will create MN in the exhaust. MN is known to be highly toxic, and closely related alkyl nitrites are known to induce respiratory sensitivity in humans. Support for the interpretation comes from many studies, including three linking asthma symptoms to methyl tertiary butyl ether (MTBE) and the observation that a POA has not been seen in regions without ether in gasoline. We also note that studies in southern California show a historical trend from more significant to less significant ozone-health associations. The timing of those changes is consistent with the known timing of the introduction of gasoline oxygenated with MTBE in that region.     

湘鄂赣农业资源与专业化区域化方向

湘鄂赣地理位置优越,农业资源丰富,稻谷、茶叶、麻类、棉花、油料、柑桔和淡水产品、禽蛋、肉类等在我国居有重要的地位,因此,大力发展三省农业生产,对我国人民实现小康生活具有战略意义。今后,要加速专业化区域化进程。我们找出生产潜力所在:改造低产田、低产园、低产水面;开发“三高”技术;开垦荒地、荒山、荒水;适当提高复种指数。通过建设,三省主要农产品将自给有余,还可满足国内外市场的需要。努力方向:高效农业开发——综合农业开发,吨粮田开发,玉米带开发,饲料稻开发,山区开发;合理布局农业生产;深化农业商品基地建设,发展综合利用,搞活商品流通;全面提高农业现代化水平,加强农业社会服务体系。     

Latitudinal variation in size of freshwater pulmonate mollusks (Mollusca: Gastropoda: Pulmonata) in Western Siberia

The size of shells in some freshwater pulmonate mollusk species abundant in Western Siberia (Lymnaea fragilis, L. terebra, Planorbis planorbis, and Anisus leucostoma) is relatively large in the south and decreases in the north. It is supposed that this phenomenon is explained by the fact that the season with conditions allowing the growth of mollusks is shorter in the north than in the south of Western Siberia.     

Prognosis of the spatiotemporal dynamics of ecosystems by means of universal kriging

The use of quantitative data for constructing prognostic maps of the dynamics of ecosystem degradation and restoration by nonlinear simulation methods is a topical field of landscape ecology. This method of dynamic cartography is based on fiberwise comparison of data on the state of Chernye Zemli (the Kalmyk Republic, Russia) in different years and the detailed analysis of the period on which the prognosis was based. For this purpose, materials of repeated aerial and satellite photography obtained during a long period (1954–1993) were used. Comparison of maps characterizing the dynamics of Chernye Zemli between 1958 and 1993 allows prognostic electronic maps for the next 10–15 years (with a five-year interval) to be drawn and land prognosis for the next 20–30 years (1998–2023) to be obtained. Deceased     

Distributions of personal VOC exposures: a population-based analysis

Information regarding the distribution of volatile organic compound (VOC) concentrations and exposures is scarce, and there have been few, if any, studies using population-based samples from which representative estimates can be derived. This study characterizes distributions of personal exposures to ten different VOCs in the U.S. measured in the 1999-2000 National Health and Nutrition Examination Survey (NHANES). Personal VOC exposures were collected for 669 individuals over 2-3 days, and measurements were weighted to derive national-level statistics. Four common exposure sources were identified using factor analyses: gasoline vapor and vehicle exhaust, methyl tert-butyl ether (MBTE) as a gasoline additive, tap water disinfection products, and household cleaning products. Benzene, toluene, ethyl benzene, xylenes chloroform, and tetrachloroethene were fit to log-normal distributions with reasonably good agreement to observations. 1,4-Dichlorobenzene and trichloroethene were fit to Pareto distributions, and MTBE to Weibull distribution, but agreement was poor. However, distributions that attempt to match all of the VOC exposure data can lead to incorrect conclusions regarding the level and frequency of the higher exposures. Maximum Gumbel distributions gave generally good fits to extrema, however, they could not fully represent the highest exposures of the NHANES measurements. The analysis suggests that complete models for the distribution of VOC exposures require an approach that combines standard and extreme value distributions, and that carefully identifies outliers. This is the first study to provide national-level and representative statistics regarding the VOC exposures, and its results have important implications for risk assessment and probabilistic analyses.     

Geographic Variation in the Seasonal Reproductive Strategy of the Mite Varroa jacobsoni in the Honeybee Nest

Variation in the reproduction of Varroa jacobsoni mite was studied in relation to the expansion of the range of its parasitism on the honeybee. Geographic differences in the seasonal dynamics of mite reproduction in the nests of bee families were revealed. Variation in the sex ratio of mites and the factors inhibiting their reproduction at the northern boundary of the honeybee range are considered. The forms of parthenogenetic reproduction in V. jacobsoni are discussed.     

Long-term increase in climatic dryness in the East-Mediterranean as evidenced for the island of Samos

The Eastern Mediterranean region is among the regions which were predicted to become drier under IPCC climate scenarios. Here, we document a gradual reduction of rainfall and tree growth and the loss of rural springs during the last decades of the twentieth century. Years with severe drought are associated with very low tree growth (dendrochronology) and dry falling of springs as evidenced by interviews with local stakeholders. The paper discusses the consequences of accelerating drought on natural vegetation and agriculture and points at the interaction with fire dynamics and economy, both likely to enhance the drought effect.     

Comparative analysis of the effect of predator odor on morphological and physiological parameters of adult male Campbell hamsters (<Emphasis Type="Italic">Phodopus campbelli</Emphasis>) and dwarf hamsters (<Emphasis Type="Italic">Phodopus sungorus</Emphasis>)

The effect of long-term exposure to natural excretions of the European polecat on the morphological parameters and hormonal status of adult male Campbell hamsters (Phodopus campbelli) and dwarf hamsters (Ph. sungorus) was studied. Exposure to volatile components of natural excreta of a potential predator did not have any significant effect on hamsters. The combined influence of volatile and nonvolatile components of the polecat’s excretions caused physiological stress in Ph. campbelli, while in Ph. sungorus, on the contrary, an increase in thymus weight and the plasma testosterone level was recorded.     

How Do Groups Solve Local Commons Dilemmas? Lessons from Experimental Economics in the Field

The use of experimental settings to observe human behaviour in a controlled environment of incentives, rules and institutions, has been widely used by the behavioural sciences for sometime now, particularly by psychology and economics. In most cases the subjects are college students recruited for one to two hour decision making exercises in which, depending on their choices, they earn cash averaging US$ 20. In such exercises players face a set of feasible actions, rules and incentives (payoffs) involving different forms of social exchange with other people, and that in most cases involve some kind of externalities with incomplete contracts, such as in the case of common-pool resources situations. Depending on the ecological and institutional settings, the resource users face a set of feasible levels of extraction, a set of rules regarding the control or monitoring of individual use, and sometimes ways of imposing material or non-material costs or rewards to those breaking or following the rules. We brought the experimental lab to the field and invited about two hundred users of natural resources in three Colombian rural villages to participate in such decision making exercises and through these and other research instruments we learned about the ways they solve - or fail to - tragedies of the commons with different social institutions. Further, bringing the lab to the field allowed us to explore some of the limitations of existing models about human behaviour and its consequences for designing policies for conserving ecosystems and improving social welfare.