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Background The German energy transition strategy calls for a reform of the German energy sector. As a result, the German Renewable Energy Sources Act (EEG) passed in 2000 is widely regarded as successful legislation for promoting bioenergy development. More than 1000 biogas plants were constructed in Central Germany (CG) between 2000 and 2014. Despite this, few studies have been conducted for this period, which systematically investigate how environmental, social and economic factors, as well as various EEG amendments have impacted biogas production or what the environmental consequences of biogas production development in CG have been. Methods The impacts of environmental, social and economic factors and different EEG amendments on biogas production decisions in CG were quantified using a multivariate linear regression model and the event study econometric technique. A GIS-based spatial analysis was also conducted to provide insight into the changes to agricultural land use that resulted from the development of biogas plants during the EEG period. Results The main finding was that the income diversification effect resulting from biogas production was the most important factor in a farmer’s decision to adopt biogas production. In addition, all of the EEG amendments had a significant influence on the adoption of biogas production; however, EEG III and IV, which tried to promote small-scale plants, were unable to reduce the average size of the plants constructed in these two amendment periods. From a landscape perspective, there was a striking increase in the cultivation of silage maize in CG from 2000 to 2014. Silage maize was intensively cultivated in regions with a high installed biogas plant capacity. Since the first EEG amendment, permanent grassland area slightly increased while arable land area declined in CG. Conclusions The adoption of biogas production in CG was strongly driven by economic incentives for the farmers, more precisely, by the incentive to diversify their income sources. In addition to increase the subsidy, future EEG amendments should find new measures to encourage the adoption of small-scale biogas plants, which had been unsuccessful in EEG amendments III and IV.

With the accelerating process of economic globalization, the deep adjustment of the international industrial division of labor, and the continuous upgrading of the global value chain, the development of the service industry has entered into a new historical period. This study analyzes the dynamic evolution of trade network structure at three levels: macro, mesa, and micro, and empirically explores its influencing factors. Taking national service trade as the research object, this study analyzes the topological structural characteristics of the food trade network of “One Belt and One Road” countries by selecting indicators such as network point degree, average path length, trade intensity, intermediation degree, and aggregation coefficient, and further explores the characteristics of association network structure in national service trade network using block model. The topological structural characteristics of the “Belt and Road” trade network are analyzed from three aspects: overall, local, and individual. Then, we construct a regression model to analyze the factors influencing the dynamic evolution of the service trade network structure of the countries along the “Belt and Road” through the QAP method. Finally, based on the summary of the research findings, this study puts forward the corresponding considerations and policy recommendations from the perspectives of regional, directional, and reciprocal investment, to benefit more efficient and strategic national service trade under the framework of “Belt and Road.” Based on the results of this study, this study proposes the following policy recommendations: firstly, actively promote the service trade cooperation with other countries to optimize the market layout; secondly, promote the service industry reform to extend the length of the value chain and improve its position in the value chain; and thirdly, jointly promote the infrastructure construction of “Belt and Road” with other countries, promote trade liberalization, and reduce the trade volume. Secondly, we should promote the reform of the service industry, extend the length of the value chain, and improve our position in the value chain. Finally, we should vigorously promote the development of innovation, promote the two-way opening of new service industries, adhere to the “going out” strategy, and cultivate high-quality and excellent technical talents, to promote the overall improvement of the innovation-driven capacity of the service industry with a people-oriented approach.

In daily life, the nutrients taken from the food of the human body are often insufficient or surplus, which has a negative impact on human health and waste of agricultural nutrients as well. There is some catering software that can guide people about the intake of the nutrients at home and abroad, but they can only realize the analysis function, that is, tell the user that the nutrients intake is inadequate or exceed the standard. This paper constructs an optimal allocation system of the agricultural products components of the nutrition and health care based on internet of things, allowing people to use it at home or in the hotel. Based on the users free ordering meal, analyze and optimize the users meal according to different types of users with different matching allocation model, guide the user to adjust the meal to meet their nutrient needs, finally reach the purpose of users adjustment of the dietary structure.