陕西省粮食安全定量评价研究

从粮食自给率、人均粮食占有量、粮食单产水平、人均耕地、粮食生产波动系数等方面构建粮食安全综合指数,采用粮食安全系数评价法,对陕西省11个地市1998~2007年的粮食安全状况进行定量评价。结果表明,在最近10年里陕西省粮食安全总体是安全的,但是各地市差异明显。由粮食安全综合评价值F的大小可以将陕西省粮食安全大致分为3类地区:关中地区的咸阳、渭南、宝鸡属于粮食安全区;铜川、榆林、安康属于粮食临界安全区;其他地区属于粮食基本安全区。影响陕西省粮食安全的主要因素是人口持续增长、土地资源短缺、粮食生产分布不平衡、粮食生产环境恶化等。认为应该从保护耕地、水利建设、商品粮基地建设、粮食储备以及粮食预警等方面保障陕西粮食安全。     

生态安全对防止耕地隐性流失和保证粮食安全的意义

从生态安全的角度探讨了我国的耕地流失和粮食安全问题。笔者认为,生态退耕和农业结构调整所引起的耕地面积减少不应简单地算入耕地流失之列。应从大农业的角度看待农用土地在不同利用方式下的合理转换。畜牧业等农业内部产业的用地固然会减少粮用耕地的面积,但会减轻畜牧业以及人类消费对粮食的需求。各种形式的生态劣变是耕地资源流失和耕地质量下降的主要原因。生态退耕应看作是对土地资源的一种保护措施和对耕地资源贮备形式。由于国民生活水平的提高和食物结构趋于多样化,口粮在食物构成中的比例趋于减少,简单以粮食占有量来评价国家粮食安全形势是不够全面的。从人体营养需求、国家粮食生产能力、消费趋势、国际市场潜力等方面分析了我国的粮食安全问题。由于人口增长缓慢,利农政策及价格对粮食生产的刺激,以及国际粮食生产和市场的巨大潜力,我国的粮食安全不存在大的问题。     

陕北黄土高原农牧交错带粮食供需测算

在分析陕北黄土高原农牧交错带植物性产品和动物性产品生产能力以及粮食总供给量的基础上,测算出无论是现在,还是2005、2015和2030年,粮食生产都难以满足需求.产生粮食供需矛盾的原因主要是人口增长过快,非农建设占用耕地,退耕还林还草,以及农牧业生产效率较低等原因,并提出了相应解决途径.     

基于自然脆弱性的中国典型小麦旱灾风险评价

虽然中国的粮食产量在过去的几十年中一直保持着稳定的增长,但全球气候变暖及其可能导致的干旱的增加,将对中国的粮食安全产生一定的影响。基于自然脆弱性农作物旱灾风险理论,在利用中国40年的日气象数据刻画出我国小麦的旱灾致灾因子强度,利用EPIC(environmental policy integrated climate)中的农作物生长模块模拟出典型小麦品种的自然脆弱性曲线的基础上,对中国小麦旱灾风险的时空分布规律进行了定量评价。结果表明:小麦旱灾产量损失率从西北向东南方向递减;中国农牧交错带是小麦旱灾产量损失率的界线;小麦旱灾脆弱性的非线性特点,对灾情损失具有一定的放大和缩小作用。     

2016版食品中农药最大残留限量标准简介

建立我国的食品安全标准体系是保障我国人民身体健康的重要措施,本文介绍了2016版我国食品安全国家标准《食品中农药最大残留限量》(GB 2763)制定最新进展,并对标准制定情况进行了简要分析。新版食品安全国家标准中共包括4 140项农药残留最大限量。     

国外食品中农药残留监测概况

本文简要介绍了近年世界卫生组织和联合国粮农组织在保证食品安全中对农药残留的管理情况、各国农药多残留分析方法进展 ,以及欧美和日本等国对食品中农药残留监测的概况 ,并对我国开展农药残留监测和加强管理提出建议     

DDT and DDE in the blood and diet of eskimo children from Hooper Bay, Alaska

An analysis of the levels of DDT and DDE in the blood of some Alaskan Eskimo children and in the fat of some local marine mammals taken for food suggests that the children's pesticide burdin is only modestly lower than that of other American children. Authors suggest that some other food source, perhaps packaged food, supplies a portion of the dietary chlorohydrocarbon pesticide.     

陕北黄土丘陵沟壑区退耕还林对粮食安全的影响——以榆林市米脂县为例

以榆林市米脂县为例,选择最小人均耕地面积和耕地压力指数模型对其退耕还林工程实施前后的粮食生产进行了对比分析;以1995~2005年的统计数据为基础,运用GM(1,1)模型预测了该县2010年的粮食供需前景。研究结果表明:与退耕前相比,米脂县的最小人均耕地面积减少了25.15%,耕地压力指数增加了7.99%;粮食供需预测显示,2010年米脂县粮食总供给量为42522 t,当人均粮食需求量分别为190kg、230kg、260kg时,粮食总需求量为39847 t、48236 t、54527 t,粮食盈余率为6.29%、-13.44%、-28.23%。这说明在低的需求下,目前退耕还林工程没有对该县的粮食安全构成较大威胁,但随着需求水平提高粮食安全威胁迅速加大。因此,决不能对粮食安全放松警惕,并据此提出了保证未来粮食安全的有效途径。     

粮食生产系统的能值分析--以安塞县为例

应用OdumH.T创立的能值理论分析了安塞县粮食生产系统后认为:该县粮食生产系统能值投入率与产出率"双低",应增加系统投入以提高产出水平;系统环境负荷率不高,不可更新环境资源破坏严重,应提高可更新环境资源利用效率、加强水土保持工作;辅助能值投入中有机能值略高于无机能值,应按适当比例增加辅助能值投入以提高系统生态经济效益;粮食产出能值中玉米、豆类所占比重高,系统结构调整应遵循生态经济原则,保持或压缩口粮作物、提高粮饲两用作物播种面积,同时发展舍养畜牧业和粮食加工业。     

Integrated pest management in a cotton-growing area in the Southern Rift Valley region of Ethiopia: development and application of a supplementary food spray product to manage pests and beneficial insects

Cotton crop Ethiopia is a high-value crop and the strategy for pest control is insecticide-dependent with no consideration of beneficial insects. We carried out a study in 2013 and 2014 to determine the effectiveness of a food spray product developed with local ingredients from Benin (BFP), a food spray product developed from Ethiopian ingredients (EFP), and mixtures of the individual food spray products with and without neem extracts. Applications of BFP and of EFP alone attracted and retained beneficial insects and significantly reduced the number of pests, and increased cotton yields and profitability. The net margins of 18,418 and 18,642 Ethiopian birr (ETB)/ha were achieved from the plots treated with BFP and EFP, respectively, and 13,000 ETB (US$1 = 19 ETB) was achieved from the unsprayed plots. Addition of neem extract to the food spray products decreased the number of beneficial insects attracted to the food spray plots. In conclusion, food sprays can be used as part of integrated pest management (IPM) for managing cotton pests and can result in significant increases in crop yields and profitability.     

食品中农药残留膳食暴露评估若干问题探讨

文章从中国制定食品中农药最大残留限量(MRL)标准和进行农药残留膳食暴露评估常用的术语及模型出发，就相关研究及数据选择中易出现的问题，如定义不准确、数据选择偏差、模型模糊、结论依据不足等进行了分析评述，提出了作者的见解和观点，以期加深理解，达成共识，正确应用风险评估原则，完善风险评估研究方法，从而提高风险评估对食品中农药残留管理的支撑水平。     

陕西省粮食安全区域差异及驱动因素分析

随着农业的基础地位在经济化和城市化的浪潮中逐渐削弱,粮食安全重新成为世人关注的焦点。本文以陕西省的11个地区为例,借助于SPSS统计软件,采用主成分分析法分析陕西省粮食安全水平的区域差异,表明粮食播种面积、耕地面积和粮食生产的科技投入对粮食安全的影响最大,人口与其他农业产业也对粮食安全产生一定影响。渭南市、咸阳市和西安市的粮食安全综合得分最高,分别为12.903、11.513、8.693,粮食安全水平较高;粮食安全综合得分较低的三个地区是杨凌示范区、铜川市和商洛市,粮食安全水平较低。     

Temperature and food availability effects on spinosad and malathion against <Emphasis Type="Italic">Rhagoletis indifferens</Emphasis> (Diptera: Tephritidae) in the laboratory

Western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), is a quarantine pest of cherries (Prunus spp.) in western North America that is managed primarily using insecticides. Different insecticides could vary in efficacy and ability to control flies depending on environmental factors. Here, the objective was to determine if temperature and food availability affect the efficacies of spinosad and malathion against R. indifferens in the laboratory. Fourteen- to 18-day old flies were exposed to sweet cherries with dried residues of spinosad and malathion at 19 or 21 versus 27 °C with or without yeast extract + sucrose food (‘food’). Deaths and oviposition were recorded over four days. In spinosad treatments, fly kill was greater at 27 °C than at lower temperatures when there was no food, but in the malathion treatments, kill did not differ between temperatures and it was greatest when there was no food. In spinosad treatments, lower oviposition occurred at 19 or 21 °C than 27 °C, with differences larger when there was food. However, in malathion treatments, oviposition was not affected by temperature although it was lower when there was no food. Results imply temperature and food availability could be factors affecting R. indifferens control in cherries, but whether temperature is such a factor depends on the insecticide used.     

额河银鲫食性的初步研究

对额河银鲫的食性和年龄与生长关系进行了调查研究。结果表明：额河银鲫是一种杂食性鱼,它的主要食物组成是藻类、水生植物、原生动物、水生混虫、轮虫以及小鱼等。在食物成分上有性变化。在春季和夏季主要摄性食物而秋季主要摄食动物性食物。     

DNA分子检测技术在节肢动物食物网结构解析中的应用

生态系统中节肢动物食物网结构错综复杂，通过观察和解剖等传统手段往往很难精准地获得物种种类及彼此之间食物关系的全面信息。近年来，DNA分子检测技术快速发展，显著促进了节肢动物食物网复杂结构的系统解析，有效实现了食物网结构分析由定性向定量的重要转变。该文介绍DNA分子检测的主要技术及其优缺点，列举其在节肢动物食物网结构分析中的应用实例，讨论DNA分子检测技术在应用中遇到的问题及挑战，旨在为节肢动物食物网结构分析提供科学依据和技术指导，有力推进农田等不同生态系统中节肢动物食物网结构及其生态功能的深入研究和挖掘利用。     

国际食品法典委员会动物源性食品中农药最大残留限量制定现状

动物源性食品中的农药残留越来越受到社会关注,但是目前基于我国试验数据开展的膳食风险评估和最大残留限量推荐实践非常少.本文结合农药残留专家联席会议(JMPR)评估实践,重点介绍了评估所需试验数据的要求、动物源性食品中农药残留水平的估算、膳食风险评估和最大残留限量推荐的方法,分析了国际食品法典委员会(CAC)动物源性食品中...     

农田节肢动物食物网结构与天敌控害功能

传统的节肢动物群落多样性研究主要关注物种的丰富度、群落结构及其动态变化,难于深入解析多物种间的复杂作用关系及生态功能的内在驱动机制。节肢动物食物网组建及结构分析,可以评价不同营养层级物种间的相互作用,进而阐明天敌生物控害作用等食物网功能的调控机制。该文系统梳理了农田节肢动物食物网的组成和评价方式,介绍其结构与功能关系,并结合食物网理论在害虫生物防治中的应用实践,总结物种内部作用和外界环境变化对食物网结构及功能的影响,深化了对食物网结构介导的天敌控害功能的认识,为优化农田害虫生物控制理论提供了参考。     

Problem Identification and Knowledge Acquisition for the Solution of Pest Problems: A Suggestion for a Comprehensive Approach

The reduction of pre- and post-harvest yield losses due to pest attack represents a substantial contribution to the increase in food supply which will be absolutely essential in future. Not only must more food be produced but, in addition, this must be accomplished in an ecologically, economically and socially sustainable manner in a broader concept of food security improvement and poverty alleviation. Integrated pest management can play a key role in this process. Firstly, constraints and anticipated global food production requirements are presented in an overview. This is followed by a discussion of the various knowledge acquisition techniques for identifying and eliminating knowledge gaps with a view to solving pest problems in a systematic manner. It is concluded that the development of better integrated approaches based on an expanding theoretical, methodological and empirical basis will produce solutions which are more effective, sustainable and competitive compared with the currently prevailing procedures for pest problem solution.     

Density ofAlabama argillacea larvae affects food extraction by females ofPodisus nigrispinus

The food extraction by adult females ofPodisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) from 3 ^rd instarAlabama argillacea (Hübner) larvae was evaluated in the laboratory. The densities studied were converted to weight of prey offered: 15.7 (one larva); 44.1 (three larvae); 71.4 (five larvae); 117.4 (seven larvae) and 148.8 mg (nine larvae). The adult weight, the amount of food consumed, the weight of remaining larvae and the time taken to ingest the food were recorded every 24 h during 9 days to estimate the percentage of food consumed, the quantity and the percentage of food extracted from each larva, the quantity of food extracted per minute and the relative consumption rate. The quantity of food consumed (88.5% to 35.5%) and extracted (90.8% to 35.5%) byP. nigrispinus females from each larva decreased as the food available increased. The time spent byP. nigrispinus to ingest food and the quantity of remaining food were similar during the 9-day period of the adult stage of this predator. No interactions were observed between the age of females of this predator and the prey density. The weight gained (1.2–5.8 mg/9 days), body weight (35.5–42.3 mg) and the relative consumption rate (0.4–1.4 mg/mg/day) by females of this predator increased at a declining rate with the quantity of food available.P. nigrispinus may change its predatory behavior as a function of food available. http://www.phytoparasitica.org posting Dec. 25, 2007.     

Effects of the nematode Phasmarhabditis hermaphrodita and of venom from the endoparasitic wasp Pimpla hypochondriaca on survival and food consumption of the pest slug Deroceras reticulatum; implications for novel biocontrol strategies

BACKGROUND: Controlling pests through disruption of biochemical pathways by physiologically active compounds/factors from animals and plants represents an expanding field of research. The authors investigated whether such factors in venom from the wasp Pimpla hypochondriaca (Retzius) can affect the viability and food consumption of the slug Deroceras reticulatum (Müller), and whether they can improve the efficacy of nematode-induced slug mortality. RESULTS: Exposure of slugs to 4 mL of water containing 500, 1000 and 5000 Phasmarhabditis hermaphrodita (Schneider) resulted in significant increases in mortality (with hazard ratios of 3.5, 3.9 and 5.8 respectively) and significant reductions in total food consumption and mean food consumption each day for 21 days. Injection of slugs with 4, 8 or 12 microL of P. hypochondriaca venom resulted in significant increases in mortality (with hazard ratios of 3.3, 4.5 and 9.0 respectively) and significant reductions in total food consumption compared with the controls. However, there was no significant effect of venom on the mean food consumption on individual days of the 21 day assay period, although significant reductions occurred for the 8 and 12 microL doses up to day 10. Injecting slugs with 4 microL of venom prior to exposure to 500 nematodes had no synergistic effect on either mortality or food consumption compared with either of the individual treatments. CONCLUSIONS: Pimpla hypochondriaca venom contains factors capable of killing and reducing food consumption by D. reticulatum. The utilization of these factors as components of integrated pest management strategies is discussed.