Optimal forecast evaluation: fertilizer prices

High fertilizer price volatility makes production planning and inventory management difficult, so accurate fertilizer price forecasts would be beneficial. This article evaluates commercial forecasts for urea and diammonium phosphate (DAP) prices based on forecast accuracy and optimal forecast properties. Most forecasts pass the tests, but forecasts for the US New Orleans urea and the US Gulf DAP markets, in particular, do not and thus show potential to be improved.     

农户减少化肥用量和采用有机肥的意愿研究——基于洱海流域上游面源污染防控的视角

[目的]过量施用化肥导致水体富营养化是造成洱海流域上游面源污染的主要原因之一,调查分析农户减少化肥用量和采用有机肥的意愿有助于了解其调整施肥结构的行为。当前研究忽视了农户减少化肥施用强度和采用有机肥的意愿间的替代性,未能开展联立研究。[方法]基于洱海流域上游397个水稻种植户的问卷调查数据,通过Bivariate-Probit模型对农户减少化肥用量和采用有机肥两种意愿进行分析。[结果]年龄负向影响农户减少化肥量的意愿,农户对有机肥好处的认知正向影响其减少化肥量的意愿,农户参加农业社会化服务对其减少化肥用量和采用有机肥的意愿均产生正向影响,相比之下,对农户采用有机肥意愿的促进作用更大。[结论]引导农户参加农业社会化服务以及加强宣传和培训,提高农户对有机肥作用的认知可能是加强其减少化肥用量和增加有机肥施用量意愿的有效途径。     

The Impact of Sustainability Aspects in the Meat Sector: A Cluster Analysis Based on Consumer Attitudes and Store Format Choice

Several consumer studies have shown considerable market potential for sustainable meat products, however, their markets shares are still marginal. In Germany, the sustainable aspects “organic,” “local origin,” and “animal welfare” are of special interest. To obtain a precise overview of potential target groups for these meat categories and their choice of store format, 620 German consumers were surveyed on their attitudes toward sustainable meat production and their shopping behavior. First, target groups based on consumers’ attitudes were identified by cluster analysis, taking into account possible overlaps. Consumers were also clustered by their store format choice and their preferred type of meat packaging. A cross tabulation of the results then provided insights into which store format and type of meat packaging is preferred by the target groups for sustainable meat products. Due to overlaps found in the target groups, the existence of important subgroups was shown. Amongst the target groups, only a slight preference for unpackaged meat products was found. Basically, the offer of sustainable meat products appears of interest for all store formats, with particular emphasis on supermarkets. The results of this study can support producers and retailers developing new and tailored marketing strategies for sustainable meat products.     

农户生物菌肥购买意愿及行为的影响因素研究*——基于山东省设施菜农的调研数据

[目的]生物菌肥对于土壤改良、环境改善、食品安全具有重要意义,但目前生物菌肥在整个肥料产业中所占份额较小,迫切需要探讨如何从农户角度提高生物菌肥的施用比例。[方法]基于设施蔬菜农户的数据,构建Bivariate Probit模型,对农户生物菌肥的购买意愿和行为的影响因素进行比较研究。[结果]农户的生物菌肥购买意愿和行为总体上呈现一致性,愿意购买的农户中有97. 77%的农户具有实际的购买行为;但两者的影响因素有所差异,从差异因素来看,质量安全检测对购买意愿具有显著的正向影响,但对购买行为的影响并不显著;农户文化程度、种植年限、对无公害、绿色、有机蔬菜的了解程度,经销商推荐,施肥指导对购买行为具有显著的正向影响。从共同因素来看,生态环境认知变量对购买意愿和购买行为影响不显著。[结论]要推广生物菌肥,需要进一步加强质量安全检测体系对农业行为的约束性,提升经销商的规范经营意识,采用集中招标等灵活的价格政策,提升农户的生态技能,并在保护生态环境方面出台更完善的农业绿色发展政策。     

"利剑斩污"行动下石家庄市挥发性有机物的污染特性变化研究

为研究石家庄市在"利剑斩污"行动管控期和非管控期挥发性有机物(VOCs)的污染特性变化,在2个时间段内对石家庄市3个国控点进行采样分析。通过苏玛罐(SUMMA罐)进行样品采集,利用气相色谱/质谱联用(GC/MS)仪对石家庄市区3个国控点的VOCs进行定性定量检测分析。结果表明,监测期间主要的特征污染物是二氯甲烷、二氯丙烷、苯和甲苯。与非管控期间相比,管控期间各污染物的质量浓度均有所降低,总VOCs平均质量浓度降低45.107μg/m~3,二氯甲烷质量浓度降低8.796μg/m~3,二氯丙烷质量浓度降低3.750μg/m~3,苯质量浓度降低18.285μg/m~3,甲苯质量浓度降低16.895μg/m~3。大气环境调控策略的实施,有效降低了VOCs浓度,减少了空气污染程度,空气质量改善效果显著。"利剑斩污"行动期间采取的相关举措,对于制定常态化下VOCs的防治对策具有一定的参考价值。     

Are international environmental policies effective? The case of the Rotterdam and the Stockholm Conventions

This is the first paper to show that participation in an international environmental agreement has some effectiveness. Our identification strategy consists of applying difference-in-differences techniques in a panel data framework to various levels of data aggregation. We find that ratification of the Rotterdam Convention (RC) and the Stockholm Convention (SC) leads to a reduction in trade of hazardous substances from OECD to non-OECD countries. In particular, we find that when the exporter ratifies the RC, there is a reduction in the import of hazardous chemicals of about 7 percent. In the case of the SC, the results show significant reductions of around 16 percent in trade shipments of persistent organic pollutants. This reduction is more than double the effect found for the RC, which was expected due to a more restricted obligation imposed by the SC convention.     

Factors Influencing Organic and Fair Trade Coffee Growers Level of Engagement with Cooperatives: The Case of Coffee Farmers in Mexico

We study the factors influencing the percentage of organic and fair trade certified coffee sold through a cooperative by growers of five cooperatives in Mexico. The percentage of coffee sold through the cooperative was used as a proxy of growers’ engagement with a cooperative. Using factor analysis and a fractional probit regression, we evaluated the proposition that the level of engagement can be explained by transaction cost economics, social norms and connections, and farmer and farm business characteristics. We found that farm size, uncertainty regarding cooperative time of payment to the members and cooperative commitment on price to be paid negatively influence the level of engagement. In contrast, asset specificity, relational commitment, and price have a positive impact on engagement. Our results may help cooperatives and policy makers to build strategies aiming to increase this level of engagement. This is relevant because lower grower engagement has been found to be positively correlated with weak performing cooperatives.     

化肥价格变化对粮食价格的影响研究--基于省际动态面板数据模型的系统GMM检验

基于我国粮食价格与化肥价格变动趋势的分析,运用2006年~2017年省际动态面板数据模型和系统GMM方法,实证检验了化肥价格变动对粮食价格的影响。结果表明:化肥价格变动对粮食价格存在显著的正向影响,在考虑化肥价格影响下,农业生产服务、种子等农资价格对粮食价格也存在显著的正向影响,机械化农具和农药价格对粮食价格不显著,"价补分离"政策对粮食价格存在显著负向影响。因此,在化肥减量行动背景下,适度调控化肥价格,避免化肥价格上升挤占粮农利润,大力发展农业生产性服务业和种子业,继续实行"价补分离"政策,提高补贴精准性,减少农民投入成本。     

民办院校有机化学实验多元化教学模式探索

民办院校把有机化学实验作为有机化学教学的重要组成部分,多元化教学模式主要从教学方法与手段、教学内容、学习方式、考评体系等方面进行多元化教学模式探索。建立以微课视频、翻转课堂、问题引导,依托基础性实验、综合型实验和创新型实验,依托多元化信息化的教学手段雨课堂、虚拟仿真情景模拟实验、超星尔雅平台,融合多种教学方法,结合“线下”翻转课堂,建立多元化教学模式。这种多元化教学模式能有效提高学生的学习主动性和创新能力。     

Cooperation and Competition in the Context of Organic and Mechanic Worldviews – A Theoretical and Case based Discussion

In this study we argue that there is an interconnection between; the mechanistic worldview and competition, and the organic worldview and cooperation. To illustrate our main thesis we introduce two cases; first, Max Havelaar, a paradigmatic case of how business might function in an economy based upon solidarity and sustainability. Second, TINE, a Norwegian grocery corporation engaged in collusion in order to force a small competitor out of the market. On the one hand, in order to encourage market behaviour that integrates economic, societal and environmental values we find that transparent cooperation within a context of an organic worldview takes care of important intrinsic as well as instrumental values. On the other hand, we find evidence for asserting that cooperation based upon a mechanistic worldview, typically leads to group egotistical consequences undermining the long term common good.