Browsing by Person "Yu, Xiaomin"

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Towards sustainable chemical fertilizer management in China : from theory to farm household
(2023) Yu, Xiaomin; Doluschitz, Reiner
Over the past few decades, China’s grain production has expanded drastically. On the one hand, this has eliminated food shortages and allowed China to feed its huge and still growing population. On the other hand, the rapid growth in grain productivity has come at a heavy cost. Excessive fertilizer use has led to a variety of negative consequences that threaten national food security and environmental sustainability. Since the 2010s, the Chinese government and academia have made considerable efforts to reduce the consumption of chemical fertilizers and improve nutrient management. These include a wide range of regulations to control or guide chemical fertilizer use, policies to eliminate subsidies for the fertilizer industry, and nationwide promotion of scientific fertilizer application methods. In response to these efforts, Chinas overall fertilizer application rate has been declining since 2016. However, China still applies far more fertilizers than its crops need, and the current crop Nitrogen Use Efficiency (NUE) and Phosphorus Use Efficiency (PUE) in China are both below the global average. Therefore, reducing dependence on chemical fertilizers for crop production and sustainably feeding a large population remains a key challenge for China. This dissertation aims to contribute to sustainable nutrient management in China by providing a comprehensive and in-depth understanding of fertilizer use and management at the national, regional, farm and household levels. In the first study (Chapter 2), a systematic review of the historical development and current status of chemical fertilizer use and management in China at the national level is presented. In addition, fertilizer nutrient surpluses are estimated for 30 provinces in China and the regional and temporal variations are visualized. In the second study (Chapter 3), the relationship between fertilizer nutrient surpluses and the regional economy at the provincial level is examined within the framework of the Environmental Kuznets curve (EKC) hypothesis. A panel cointegration approach is employed, using time-series data from 1988 to 2019. In the third study (Chapter 4), the research focus is further narrowed to the farm household resolution. Using cross-sectional survey data from 774 maize-growing farms in northern China in 2019, the study investigates the role of farm characteristics, farmers knowledge, perceptions, and socioeconomic context in farmers fertilizer use strategies. The studies confirm that by 2021, China has reached zero growth in fertilizer use and fertilizer nutrient surpluses at the national and regional level. However, regions with a high proportion of cash crops, such as the southeast coast and northwest, still suffer from high nutrient surpluses. Furthermore, in circa 2012, China has reached its EKC turning point between fertilizer nutrient surpluses and GDP per capita. With further economic growth, the fertilizer surpluses in most Chinese provinces will decrease, indicating a moderating of the tension between economic development and the environment. Looking at the farm and household level, the study shows that in northern China, small farms are more likely to overuse fertilizers in maize cultivation without further yield improvement. Current extension programs have had a positive impact on farmers’ fertilizer use strategies and environmental awareness; nevertheless, the coverage and effectiveness of trainings should be improved. In summary, the dissertation identifies the following key factors that impede sustainable chemical fertilizer management in China: small farm size; regional economic dependence on cash crops; the large discrepancy between farmers practices and scientific production guidelines; and the shrinking and aging of Chinas rural labor force. To address these aspects, the dissertation proposes recommendations at the national strategic level, policy level and implementation level, respectively. The findings and recommendations of this dissertation can serve as a robust decision support and scientific basis for policy makers, stakeholders and researchers in the field of sustainable nutrient management in China.
WeChat – using social media for the assessment of tourist preferences for environmental improvements in China
(2018) Yu, Xiaomin; Siepmann, Ute; Neidhardt, Jan; Ahlheim, Michael
Environmental valuation studies with tourists have been very popular already over a long period of time. Tourists are an important stakeholder group with respect to the decision if some environmental project in a tourist region should be realized or not. Typically such studies are organized as face-to-face surveys conducted in the respective vacation areas. Tourists are asked their willingness to pay (e.g. in terms of higher entrance fees for certain amenities on site or a mark-up on accommodation prices etc.) for the implementation of an environmental project or preservation measure in that area. Based on theoretical considerations we argue that in the special case of tourist surveys internet-based surveys are preferable to face-to-face surveys under validity aspects as well as under the aspect of the representativeness of the survey results. Based on an empirical valuation study we conducted in Southwest China we illustrate the practical problems arising in the context of internet surveys in developing or threshold countries.