基于粮食安全贡献度的中国粮食主产区粮食供求格局演变

基于粮食安全贡献度的FSP模型分析框架,从省际粮食供需平衡的角度测算中国粮食主产区对国家粮食安全的贡献,并探究了粮食主产区粮食供求格局的演变特征。结果表明:除2000—2003年粮食产量骤降造成粮食供给缺口外,1991—1999年、2004—2018年中国粮食主产区粮食盈余(调出量)呈“稳中有降—绝对增长”的U型变化趋势,历年粮食安全贡献度均高于85%,粮食主产区的粮食地位相对稳固。粮食主产区的粮食供求格局经历了省际间的分化和重组。一方面,粮食供给向中北部地区集聚,而南部地区粮食产需紧平衡,粮食供需错配严重;另一方面,粮食供需空间分异明显,2000年后黑龙江、河南、吉林3省的粮食安全贡献度合计达50%左右,而湖南、江西、江苏、河北、湖北、四川、辽宁7省的历年粮食安全贡献度均低于5%,粮食调出总量合计仅占粮食主产区粮食调出总量的10%~20%。     

Challenges facing arthropod biological control: identifying traits for genetic improvement of predators in protected crops

Biological control is an efficient pest control method but there are still limitations that are hindering its wider adoption. Genetic improvement of biological control agents (BCAs) can help to overcome these constraints, but the choice of key attributes for better performance that need to be selected is still an open question. Several characteristics have been suggested but the harsh reality is that selective breeding of BCAs has received a lot of attention but resulted in very little progress. Identifying the appropriate traits to be prioritized may be the first step to reverse this situation. In our opinion, the best way is to look at the factors limiting the performance of key BCAs, especially generalist predators (pesticide compatibility, prey‐density dependence, non‐suitable crops, and extreme environmental conditions), and according to these challenges, to choose the attributes that would allow BCAs to overcome those limitations. The benefits of selection for higher resistance to toxins, whether artificially applied (pesticides) or plant produced (plant defenses); increased fitness when feeding on non‐prey food (supplemented or plant‐derived); and better adaptation to extreme temperature and humidity are discussed. In conclusion, genetic improvement of BCAs can bring about new opportunities to biocontrol industry and users to enhance biocontrol resilience. © 2020 Society of Chemical Industry     

基于信息抽取的食品安全事件自动问答系统方法研究

针对从海量食品安全事件新闻报道中很难抽取出所需答案的问题,以食品安全事件语料库为研究对象,提出了一种基于信息抽取技术的自动问答系统。首先,利用深度学习模型TextCNN对用户输入的问题进行分类,得到其所属类型。其次,对于输入问题,借助Lucene搜索引擎找到其最佳匹配文档。再次,根据输入问题的类型,从食品安全事件数据库（采用信息抽取技术自动提取的一个结构化数据库）中筛选出该文档所包含的答案候选句集合。最后,利用深度学习模型Bi LSTM及基于答案候选句上下文的特征提取方法构建一个答案抽取模型,该模型能从给定的答案候选句集合中提取出最终答案。为检查基于食品安全事件数据库的答案候选句筛选方式及基于答案候选句上下文的特征提取方式对整个自动问答系统性能的影响,进行了多种比较实验,结果表明含有基于食品安全事件数据库的答案候选句筛选方式和基于答案候选句上下文的特征提取方式的问答系统表现最佳,其回答准确率达到44%。这相比于传统的问答系统,具有明显的优势。     

气候变暖对我国水稻生产的综合影响及其应对策略

气候变暖已是不争的事实,预计到21世纪末全球地表平均气温仍将上升1.5℃以上。水稻是我国最重要的口粮作物,全国80%以上的人口以稻米为主食,探明气候变暖对我国“口粮绝对安全”的潜在影响意义重大。作者依据多年的田间增温试验及长期观察,并结合国内外现有研究,阐明了我国粮食主产区气候变暖的基本态势,总结发现温度升高1.5℃对我国水稻生产的潜在影响正负参半,并取决于具体的稻作季节和地区。但是,随着水稻种植制度调整,尤其是南方双季稻种植面积下降,温度升高对我国水稻生产的负面影响将逐步递增。最后,作者提出了应对气候变暖的气候智慧型稻作技术创新建议,并展望了该研究领域的重点内容和方向。     

不同送风和载物方式作用下冲击式速冻设备中虾仁冻结过程的比较

以明虾虾仁为研究对象,利用数值模拟结合实验验证的方法,研究两种送风方式(单侧送风和双侧送风)和两种载物方式(板带载物和网带载物)对虾仁冻结过程的影响,找到使虾仁冻结时间最短的送风和载物方式。研究发现:对于虾仁冻结来说,采用双侧送风+网带载物可以使虾仁表面流场流速更大,有利于提高换热效率,减少虾仁冻结时间,相对于其他送风方式和载物方式来说可缩短虾仁冻结时间的14%～25%;双侧送风有助于低速侧形成提高虾仁下表面流速的涡流,而网带载物可以避免在虾仁下侧面与网带交界处以及虾仁头部形成射流"真空区",上述均有助于提高虾仁表面风速,缩短虾仁冻结时长;但是冻结速度越快,虾仁冻结均匀性则越差。在本次实验中,虾仁内外最大温差出现在实验组D(双侧送风+网带载物),最大温差可达13.02℃。     

Agriculture Green Development: a model for China and the world

Realizing sustainable development has become a global priority. This holds, in particular, for agriculture. Recently, the United Nations launched the Sustainable Development Goals (SDGs), and the Nineteenth National People’s Congress has delivered a national strategy for sustainable development in China—realizing green development. The overall objective of Agriculture Green Development (AGD) is to coordinate “green” with “development” to realize the transformation of current agriculture with high resource consumption and high environmental costs into a green agriculture and countryside with high productivity, high resource use efficiency and low environmental impact. This is a formidable task, requiring joint efforts of government, farmers, industry, educators and researchers. The innovative concept for AGD will focus on reconstructing the whole crop-animal production and food production-consumption system, with the emphasis on high thresholds for environmental standards and food quality as well as enhanced human well-being. This paper addresses the significance, challenges, framework, pathways and potential solutions for realizing AGD in China, and highlights the potential changes that will lead to a more sustainable agriculture in the future. Proposals include interdisciplinary innovations, whole food chain improvement and regional solutions. The implementation of AGD in China will provide important implications for the countries in developmental transition, and contribute to global sustainable development.     

我国农作物绿色食品的生产瓶颈和生产前景

生产农作物绿色食品是农业的发展方向,也是可持续发展的必然要求,是世界范围都要引起 重视的普遍课题,我国更需迫切重视。使用一般的无公害杀虫剂是不能生产出绿色食品的,而目前病 虫害绿色防控技术还不成熟,现在可用于绿色食品生产的高效无毒的杀虫剂在我国已首先研究出来 了,当前缺少的仅是农产品市场完备的农药残留检测机制,解决这个瓶颈问题可给绿色食品创造存在 的空间,从而实现农业绿色产业大发展,这一天的到来已为期不远。     

乡村振兴战略下生鲜农产品智慧零售模式研究——以浦东新区农贸市场为例

生鲜电商是近年来颇受业界关注的零售业态。该篇文章研究的问题就是如何将生鲜电商物 流问题、高用工成本以及专业的生鲜人才储备不足等因素通过智慧零售模式同乡村振兴结合在一起, 通过实地调查和软件分析的方式提供解决农产品上行难、物流运输困难等问题的方法,为振兴乡村提 供有力的支撑。