节水农业的形成与灌溉水价改革

我国人均水资源占有量仅为世界人均水资源占有量的1/4,但目前在水资源的使用上存在着惊人的浪费现象,水资源的利用率极低。为解决水资源严重短缺的问题,可行的途径是大力普及各项节水技术,以提高水的利用率,努力建成节水型社会。当务之急是尽快建成节水型农业。而节水农业的形成首先必须依赖于水价制度的改革,利用经济杠杆以提高广大用水者的节水意识。深化水价制度的改革必须走出两个思想误区:其一是误认为农业供水成本远低于工业供水成本,所以农业水价必须远低于工业水价;其二是认为农业是弱质产业,所以农业供水已没有涨价的空间。     

实行季节性梯度农用水价对农业节水的有效性研究

从价格调控对农业用水资源的配置作用出发,分析了目前农业节水中的水价问题,得出农用水将普遍收费的必然趋势。重点提出了季节性梯度农用水价的概念并对其含义进行了深入说明。最后通过在“冬小麦节水高产省肥简化‘四统一’栽培技术体系”中的实例研究,认为季节性梯度农用水价对农业节约用水是可行的。     

基于三阶段DEA模型的广东省财政支农效率评价与政策研究

[目的]分析广东省财政支农现状及问题,评价财政支农效率,为广东省提升财政支农资金使用效率及农业高质量发展提出政策建议.[方法]运用三阶段DEA模型对广东省2000—2018年及20个市2010—2018年的财政支农效率进行测度.[结果]广东省整体财政支农效率呈现出下降趋势,纯技术效率较高,但规模效率较低导致综合效率不高...     

Marketing mix for the promotion of biological control among small-scale paddy farmers

Understanding farmers’ decision process on the adoption of biological control (BC) may help in promoting adoption. This study explored for the first time the impact of marketing mix elements (product, price, promotion, and place) on bolstering BC for the management of rice stem borer (Chilo suppressalis Walker) among rice farmers in Fuman County in northern Iran. Farmers using BC were familiar with this method primarily via village councils and rural municipality organizations (Dehyaris) and then via distributors of trichocards. Almost half of the farmers (48.3%) had weak to moderate level of contact with distributors of trichocards. All four elements (4Ps) of marketing mix (product, place, price, and promotion) were effective on the marketing of BC agents. Place (distribution) mix, followed by price mix, were the most important factors in marketing trichocards in farmers’ views. According to the sensitivity to 4Ps of marketing mix, most farmers were grouped as semi-sensitive (45.6%) and sensitive (39.4%). Overall, the availability of biological agent products in the market, the affordable price of the products, and the strong relationship of rural people with village councils and rural municipality organizations (Dehyaris) are crucial factors for BC promotion in paddy fields of Fuman.     

基于声振信号对称极坐标图像的苹果霉心病早期检测

为实现苹果早期霉心病较高精度的检测,该研究采用对称极坐标法（Symmetrized Dot Pattern,SDP）将苹果声振信号变换为雪花图,然后采用AlexNet、VGG16和ResNet50卷积神经网络以迁移学习方式深度挖掘SDP雪花图像的特征信息,将其输入到支持向量机（Support Vector Machine,SVM）分类器,对霉心程度≤7%的苹果进行检测。研究结果表明,当时间间隔系数为25和角度放大因子为50°时,健康果与早期霉心果声振信号的SDP图形状特征差异最大,在此条件下获取的SDP图经卷积神经网络AlexNet、VGG16和ResNet50提取特征并构建了不同核函数的SVM霉心果检测模型,在各类SVM模型中,ResNet50-SVM-gaus（高斯基）模型用相对较少的训练时间和参数量可取得训练集霉心果较高分类准确率,经超参数优化训练该模型对健康果和早期霉心果测试集不平衡样本（10∶1）的总体分类准确率达到96.97%,平均查准率、平均查全率、平均加权调和均值、Kappa系数和马修斯相关系数值分别为80.19%、90.36%、86.21%,82.54%和82.68%,该模型不仅对多数类的健康果保持较高分类准确率,而且对少数类的早期霉心果也具有较高判别能力。这些研究结果为声振法应用于果蔬内部病害的早期在线检测系统研发提供了技术支撑。     

农村劳动价格、收入结构变化与柑橘种植布局变迁

在农村劳动力持续转移背景下,探讨农村劳动价格、农户收入结构变化对柑橘种植布局变迁的影响,对于促进柑橘产业发展和保障农民增收具有重要意义。在理论推导基础上,利用柑橘主产省的面板数据建立固定效应模型,从全局和分区两个视角实证研究农村劳动价格、农户收入结构对我国柑橘种植布局的影响。结果表明:农业用工价格和非农就业工资的提高对柑橘种植产生负向影响,我国柑橘种植布局正由农村劳动价格较高的浙-闽-粤地区向农村劳动价格较低、以农业经营为主要收入来源的赣南-湘南-桂北扩张;工资性收入提高对柑橘种植产生的收入效应和生产总成本上涨产生的抑制效应,共同作用致使长江中游和鄂西柑橘带种植面积缓慢增长,形成我国柑橘种植“西移内扩”趋势。故而以调控农村劳动力转移、农户收入结构为切入点,是优化柑橘种植布局的重要思路。     

基于多维关联规则的猪肉价格波动影响因素分析及预测建模研究

【目的】我国是猪肉生产及消费的大国,近年来,猪肉价格波动呈现频率加快、幅度增大的趋势。猪肉价格波动不仅增加农户收益的风险性,也在一定程度上影响广大民众的生活。正确识别猪肉价格波动的影响因素并对猪肉价格波动进行科学预测,有助于确保市场健康平稳运行。【方法】运用多维关联规则定量分析生猪养殖加工产业链、替代品市场、宏观经济环境变化、突发性事件和国际市场环境等5方面共16种因素与猪肉价格波动的关联和影响程度,将挖掘得到的高相关因素作为模型输入变量,运用支持向量回归机构造提前多步的猪肉价格波动预测模型。【结果】与猪肉价格波动关联程度最高的前3位因素是生猪疫病、生猪价格和仔猪价格,置信度分别为1.00、0.93和0.82;对猪肉价格影响程度最大的前3位因素是生猪疫病、猪肉产量和出栏猪肉量,提升度分别为1.84、1.67和1.67。相较于基准预测模型,将12个高相关影响因素作为模型输入,均方根误差减少29.11%,平均绝对百分比误差减少16.00%。【结论】使用多维关联规则进行变量筛选,不仅能减少模型的变量个数,还能有效提高模型的预测精度。鉴于生猪疫病对猪肉价格波动的关键影响作用,政府相关管理部门应...     

The pelagic habitat analysis module for ecosystem‐based fisheries science and management

We have developed a set of tools that operate within an aquatic geographic information system to improve the accessibility, and usability of remote‐sensed satellite and computer‐modeled oceanographic data for marine science and ecosystem‐based management. The tools form the Pelagic Habitat Analysis Module (PHAM), which can be applied as a modeling platform, an investigative aid in scientific research, or utilized as a decision support system for marine ecological management. Applications include fisheries, marine biology, physical and biological oceanography, and marine spatial management. The GIS provides a home for diverse data types and automated tools for downloading remote sensed and global circulation model data. Within the GIS environment, PHAM provides a framework for seamless interactive four‐dimensional visualization, for matching between disparate data types, for flexible statistic or mechanistic model development, and for dynamic application of user developed models for habitat, density, and probability predictions. Here we describe PHAM in the context of ecosystem‐based fisheries management, and present results from case study projects which guided development. In the first, an analysis of the purse seine fishery for tropical tuna in the eastern Pacific Ocean revealed oceanographic drivers of the catch distribution and the influence of climate‐driven circulation patterns on the location of fishing grounds. To support management of the Common Thresher Shark (Alopias vulpinus) in the California Current Ecosystem, a simple empirical habitat utilization model was developed and used to dynamically predict the seasonal range expansion of common thresher shark based on oceanographic conditions.     

Price cointegration in spatial markets: An application to milkfish markets in Taiwan

Abstract

The objectives of this study are to analyze the interdependent behavior of lead‐lag milkfish price adjustments between vertically‐related markets (from production to consumption) as well as between five major horizontally‐related wholesale markets. Empirical results show that there is a two‐way lead‐lag cointegrating price relationship between milkfish wholesale and retail markets. Since the fish wholesale market cannot completely and quickly assimilate the retail market information, the speed of response of wholesale prices to retail price changes is relatively slow, inducing low pricing efficiency. The Taipei wholesale market appears to cause the greatest leadership impact on the milkfish price formation compared to other wholesale markets in both the long‐run and short‐run. The results also reveal that there is a high degree of integration relationship between the horizontally integrated wholesale markets (Chiayi, Changhwa and Taichung) for milkfish in the southwestern region within a short distance.     

关于完善渔业油价补助政策的探讨

从对国内外渔业油价补助政策的实践来看,该政策对于稳定渔业生产发展有着重要作用。通过会议座谈、重点调查和问卷调查等方法对我国现行渔业油价补助政策进行了调研分析,认为我国渔业油价补助方法不够科学合理,不仅与现行渔业政策不协调,还暴露出实际操作比较困难、支撑渔业油价补助发放的配套制度不够健全等问题。结合我国渔业产业实际,建议应调整完善海洋捕捞业和水产养殖业的油价补贴办法、统一细化全国渔业柴油补贴扣减政策、完善渔船管理和渔政执法管理相关制度等,提高渔业油价补助决策的科学性和民主性。