Although wastewater irrigation in agriculture could be a potential adaptation to water scarcity, its effect on crop yield varies in the literature, making it difficult to evaluate its role in global food security comprehensively.  Using agronomic experiment data from 62 studies between 1987 and 2021, we employ a meta-analysis to analyze the factors contributing to the heterogeneous effects of wastewater irrigation on crop yield.  Our findings can be summarized as (1) the mean yield growth effect of wastewater irrigation is 19.7%; (2) domestic and breeding wastewater irrigation could significantly increase crop yield, while industrial wastewater has a negative effect although not significant; (3) high nutrients concentration of domestic wastewater is significantly positively correlated with crop yield; (4) agronomic experiment designs in terms of field experiment, experiment times, and fertilizer use could contribute to the divergent crop yield effects across the studies; (5) there is a publication bias of the research results between the English and Chinese literature; (6) the literature mainly sheds light on the short-run effect, and the long-run impact shall be an important research question in the future.

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).