互联网嵌入对农户化学农药减量使用的影响——基于PSM模型的计量分析

[目的]在数字农业和绿色农业的双重背景下,探讨互联网嵌入对农户化学农药减量使用的影响,有助于实现农业数字化和绿色化发展。[方法]文章基于四川省712份微观农户调研数据,采用倾向得分匹配法实证检验了互联网嵌入是否会减少农户化学农药使用,并分析了其影响效应在不同农户群体中的异质性。[结果]互联网嵌入对农户减少化学农药使用具有显著的正向影响,其平均处理效应为0.114;互联网嵌入能有效促进小农户、专业种植大户和家庭农场减少化学农药使用,平均处理效应分别介于0.104～0.113、0.078～0.103和0.116～0.128;互联网嵌入对家庭农场减少化学农药使用的促进作用略大于小农户和专业种植大户,而相比于专业种植大户,互联网嵌入对小农户化学农药减量使用的促进作用更强。[结论]应推进农村新基建发展,提升农村互联网普及率,采取差异化的措施,鼓励家庭农场发展,引导家庭农场将互联网技术应用于农业生产,并加强互联网技术宣传与培训,提升小农户和专业种植大户嵌入互联网的能力,以促进农户减少化学农药使用。     

Milk sales and dietary diversity among the Maasai

In Maasai culture, responsibilities are traditionally divided between genders. Men are in charge of grazing and managing the livestock herds. Women take care of the family, administer food supplies, and are responsible for milking. For them, balancing home consumption of milk (for the family and for the calves), milk sale, and food purchase is a major task. In this article, we first investigate how different milk sales groups vary regarding the use of different food items and the respective quantities consumed by the enkaji, i.e., a Maasai subhousehold. Then, we address the commercialization decision and assess the effect of milk sales on the enkaji's food item use and food consumption. Using the data of Maasai enkajijik in the milk catchment area of a milk collection center in Ngerengere, Tanzania, we estimate the effects by employing propensity score matching procedures. Our findings suggest that milk sellers, especially those selling to the milk collection center, have a more diverse diet. In terms of per person consumption, the groups are markedly similar. Therefore, we conclude that income generated by milk sales is invested in diet diversification rather than in increasing the quantity of food consumed, hence the enkajijik appear not to make use of caloric terms of trade.     

Gender diversity,gender norms and firm performance: Evidence from India

This paper examines the effect of gender diversity on the financial performance of firms in India. Specifically, we examine two specific aspects of gender diversity- how the implementation of gender diversity across various workforce levels affects firm performance and the role of gender norms and culture in the external environment where the firm operates in influencing the relation. Using the World Bank Enterprise Survey, 2014, we use propensity score matching and instrumental variable estimation techniques to test the effect of gender diversity on firm performance. The results suggest that better women’s representation at higher levels of the workforce is associated with better performance. In contrast, women’s representation at the worker level of the workforce does not affect performance. Additionally, the state-level gender empowerment norms strongly condition the effect of gender diversity on performance. In states with better gender empowerment indicators, firms with better female representation at all levels of permanent employment also have better performance. In contrast, there is no effect of gender diversity on performance in states with worse women empowerment indicators.     

A specification test for the propensity score using its distribution conditional on participation

Propensity score matching has become a popular method for the estimation of average treatment effects. In empirical applications, researchers almost always impose a parametric model for the propensity score. This practice raises the possibility that the model for the propensity score is misspecified and therefore the propensity score matching estimator of the average treatment effect may be inconsistent. We show that the common practice of calculating estimates of the densities of the propensity score conditional on the participation decision provides a means for examining whether the propensity score is misspecified. In particular, we derive a restriction between the density of the propensity score among participants and the density among nonparticipants. We show that this restriction between the two conditional densities is equivalent to a particular orthogonality restriction and derive a formal test based upon it. The resulting test is shown via a simulation study to have dramatically greater power than competing tests for many alternatives. The principal disadvantage of this approach is loss of power against some alternatives.     

Waste of money or growth opportunity: The causal effect of EU subsidies on Hungarian SMEs

Although EU subsidies aiming at economic development play a pivotal role not only for Hungary but for the entire European Union as well, there is a debate regarding their effectiveness in the literature. This paper investigates the impact of direct economic development subsidies extended in the context of Structural Funds and the Cohesion Fund as part of the 2007–2013 programming period of the European Union on Hungarian micro, small and medium-sized enterprises. Based on a micro database, we evaluate the impact of corporates’ first subsidies on various performance indicators, using a combination of propensity score matching and fixed effects panel regression. According to our results, economic development funds had a significant positive effect on the number of employees, sales revenue, gross value added and, in some cases, operating profit. However, the labour productivity of enterprises was not significantly affected by any of the support schemes. Furthermore, by explicitly comparing non-refundable subsidies (grants) and refundable assistance (financial instruments), we find that there is no significant difference in the effectiveness of the two types of subsidy.     

Is there a virtuous circle relationship between innovation activities and exports? A comparison of food and agricultural firms

This study examines the existence of an interrelationship between innovation decisions and exports for food and agricultural firms as such a relationship could be the source of competitive advantages. Thus, taking as a theoretical basis the focus provided by the Resource-Based-View, the innovation and export decisions taken from 2006 to 2011 by 165 agricultural firms and 783 food companies operating in Spain (Europe) are examined here. The results of the bivariate probit and matching models used indicate a bi-directional nature of these decisions in the case of food companies and a positive though not bidirectional one in the case of the agricultural firms. Furthermore, a certain persistence is seen in the use of these decisions in both types of firms. For food companies, capital intensity and size are also determinants of innovation and exports. From the viewpoint of the decisions taken by individual firms, the bidirectional relationship could involve significant pressure in terms of the larger volume of both technological and human resources required. Agricultural and food policy decisions should incentivize these decisions given that in order to operate successfully in the global market it is necessary to acquire these competitive advantages, which also favor the growth of the agriculture and food trades.     

Collective livestock research for sustainable disease management in Mali and Burkina Faso

An international multi-disciplinary team of scientists, led by the International Livestock Research Institute (ILRI), tackled the problem of bovine trypanosomosis and the development of drug resistance in West Africa, inter alia, by the promotion of rational drug use (RDU) principles. These principles had been brought to farmers by practical training and by the provision of information leaflets. This study aimed to evaluate the impact of RDU training at smallholder level with respect to advances in farmers' knowledge and farm productivity before research outputs could be scaled up. Therefore, 508 cattle farmers attended a disease-specific knowledge test and provided information about farm production. Results show that farmers who participated in the training are more likely to identify signs and causes of the disease and to correctly administer drugs. Allocating scores to each question in the knowledge tests and scrutinizing the differences between trained and untrained farmers by matching procedures shows that participating farmers reach higher scores in all knowledge categories. Moreover, the acquisition of additional knowledge and the application of improved control strategies significantly increase farm performance. Additionally, an allocative effect was identified since trypanocide expenditures were saved by less expensive inputs.     

新一轮退耕还林对农户收入影响的机理研究 ——基于赣南、鄂北农户调查的实证分析

研究目的：新一轮退耕还林补助资金即将到期之际,分析新一轮退耕还林对农户家庭收入的净效应并揭示其内在机制。研究方法：理论上阐述了新一轮退耕还林政策促进农户收入增长的作用机理,基于赣南、鄂北地区农户调查数据,利用倾向得分匹配法进行实证分析。研究结果：（1）无论是否包含退耕补贴,新一轮退耕还林政策对农户收入有正向影响;（2）退耕林种对农户收入的作用机理不同：种植经济林的农户增加了林果业收入和非农经营收入,减少了工资性收入;种植生态林的农户通过提高工资性收入,进而提高总收入水平。研究结论：新一轮退耕还林加快了农户生计转型的进程。政策实施5年后,农户形成与生态环境相适应且稳定的生产方式,为补偿政策的逐步退出创造有利条件,实现了新一轮退耕还林政策的造血功能。     

Is There Persistence in the Impact of Emergency Food Aid? Evidence on Consumption, Food Security, and Assets in Rural Ethiopia

We identify the impact of emergency food aid programs after the 2002 drought in rural Ethiopia on future welfare. Based on a difference-in-differences matching estimator, participation in food-for-work increases growth in total consumption and food consumption eighteen months after the drought. Separately, receiving free food raises growth in food consumption, but, surprisingly, negatively impacts food security. Food-for-work benefited households in the middle and upper tail of the consumption distribution, while the better-targeted free food program benefited the poorest. Evidence suggests these impacts demonstrate accumulated and persistent effects of food aid received in the first twelve months after the drought.     

Which farmers benefit the most from Bt corn adoption? Estimating heterogeneity effects in the Philippines

The potential contributions of new biotechnologies to sustainable food and income security have been the subject of widespread discussions around the turn of the 21st century. But distributional issues of which segments of adopters of genetically modified (GM) crops benefit the most have not been given ample attention). Using propensity scores, we apply the (a) stratification‐multilevel method of estimating heterogeneous treatment effects; and the (b) matching‐smoothing method of estimating heterogeneous treatment effects proposed by Xie et al. We find that the incidence of higher yields, lower insecticide use, and reduced seed utilization in the Philippines diminishes progressively as a farmer's propensity to adopt Bt corn increases. Farmers with a low propensity to adopt Bt are those who farm smaller, nonirrigated farms located farther from seed suppliers and farmers without previous training on pest identification. In most cases, while these farmers are typically poorer farmers in smaller parcels, cannot afford irrigation and are situated in remote areas away from easily accessible seed suppliers, there is no evidence, however, that profits differ across farmers with varying propensities to adopt the Bt variety.