尽管农业污水灌溉是应对水资源匮乏的潜在适应性策略，但污水灌溉对粮食产量的影响在不同研究中存在较大差异，这使得我们难以全面评估污水灌溉对全球粮食安全的作用。基于1987—2021年62项农学试验研究数据，本文采用Meta分析方法研究了污水灌溉对粮食产量异质性的影响因素。研究结果表明：（1）污水灌溉的平均粮食增产效应为19.7%；（2）生活污水和养殖污水灌溉能够显著提高粮食产量，但工业污水灌溉的作用显著为负；（3）生活污水的养分浓度与粮食产量存在显著的正相关关系；（4）农学试验设计，如田间试验、试验次数以及化肥使用，是导致不同研究中粮食增产效应差异的影响因素；（5）粮食增产效应在外文和中文文献中存在显著差异；（6）现有文献主要揭示了污水灌溉对粮食产量的短期效应，其长期影响将是未来的一个重要研究问题。

Climate extremes, characterized by droughts and floods, have become one of the major constraints to sustainable improvement of rice productivity.  Variety choice, considered as one of the main adaptation measures, could help farmers reduce yield loss resulting from these extremes.  Based on a three-year panel survey of 1 080 Chinese rice farms in major rice producing provinces, we assume Hicksian neutral technology and employ an IV regression to estimate the average treatment effect (ATE) on rice yield for adopting stress tolerant variety, and find that farmers who adopted the stress tolerant variety on average increased rice yield by 15.5% in comparison to the non-adopters.

Air pollution negatively impacts food security.  This paper reviews the current literature on the relationship between air pollution and food security from the perspective of food system.  It highlights that agricultural emissions which substantially contribute to air pollution could happen at every stage along the food supply chain.  Meanwhile, air pollution can not only affect plant growth and animal health but also shift market equilibrium of both agro-inputs and outputs in the food supply chain and thereby affect food security indirectly.  Furthermore, this study evaluates the effects of agricultural policy and energy policy on food security and air pollution, respectively, and provides an overview of potential policy instruments to reduce air pollution while ensuring food security.  Finally, we identify the remaining research and policy issues for further studies, mainly focusing on the study of household’s bounded rational behaviors and the issue of rural aging population.  

Adopting Just and Pope (1978, 1979) style yield functions, this paper proposes a method to analyze the impacts of regional climate change on grain production in China. We find that changes in climate will affect grain production in North and South China differently. Specifically, it emerges that a 1°C increase in annual average temperature could reduce national grain output by 1.45% (1.74% reduction in North China and 1.19% reduction in South China), while an increase in total annual precipitation of around 100 mm could increase national grain output by 1.31% (3.0% increase in North China and 0.59% reduction in South China).