粮食损失研究进展和展望

我国人多地少,粮食安全事关国家安全。因此,在重视增产的同时,需要不断关注粮食损失问题。通过回顾现有粮食损失的研究,总结文献中提出的重要问题,展望未来可能的研究方向。分析表明,现有研究主要集中在：（1）减少粮食损失的目的和效果的研究。包括增加粮食供给、保障国家安全,减少不必要的资源浪费、减轻环境压力,保障粮食质量、保证食品安全,以及增加粮食价值链参与者的利润等。（2）粮食产后各环节损失水平估计及其影响因素研究。 （3）减少粮食损失的方法研究,包括品种改良、教育培训、改进储存设施等。在对现有研究综述的基础上,提出了几点展望：未来的研究应向粮食价值链下游环节拓展,对粮食质量损失程度进行定量分析,并关注粮食的最优损失水平。

The progress and prospects of research on food loss and waste

Concerns about food insecurity have grown in China due to growing population and food consumption structure improvement. The research and development practitioner has begun to focus on food loss and waste, often referred to as post-harvest losses (PHL), in China. PHL reduction has been identified as a key component to complement efforts to address food security challenges and increase farmers' incomes, especially for the rural poor. This article reviews the current state of the literature on PHL mitigation. First, we identify explicitly the varied objectives underlying efforts to reduce PHL levels. There are four main objectives of reducing post-harvest loss: (1) Improve food security and protect social stability. Reducing food loss increases the quantity of food, which can reduce the need to supplement availability through transfer programs (at household level) or via commercial imports or food aid donations. (2) Reduce unnecessary resource use and protect the environment. These resources come in the form of on-farm inputs, including water, chemical fertilizer, agrochemicals, labor, and land. (3) Improve food safety. Sometimes spoilage or contamination is not perceptible to the human senses and goes undetected, leading to adverse health effects when food is consumed. These food safety concerns have major disease and global health implications. (4) Increase profits for food value chain actors. The private sector, including smallholder farmers, plays a crucial role in making food available to consumers. Second, we summarize the estimated magnitudes of losses, evaluate the methodologies used to generate those estimates. Losses and waste can be measured in quantity and quality terms, and the commonly used loss estimation methods are case study, experimental method and questionnaire survey. So it is difficult to compare values due to differences in methods, especially the methodologies employed are often unsatisfactory. Third, we synthesize and critique the impact evaluation literature around on-farm and off-farm interventions expected to deliver PHL reduction. They include: (1) Improved varietals. Because of the compounding effects of pests and deterioration accumulated before harvest, interventions that aim to reduce PHL while crops are still in the field is arguably more effective than deploying strategies that only start after harvest. (2) Education on best practices in harvest and post-harvest handling. Interventions also occur around education for best practices in harvest and post-harvest handling, generally in the form of extension messaging. (3) Chemical sprays in storage. Many farmers use some form of chemical or natural spray during home-based storage as a means of keeping pests and insects away from food, but it may lead to negative environment or health effects. (4) Improved storage of grains through advanced technologies. The most widespread intervention strategy is the use of improved storage devices such as metal silos. (5) Integrated pest management in storage. The integrated pest management paradigm is generally discussed with respect to the prevalence of pests pre-harvest, but IPM can also be useful during storage. (6) Other methods include improving infrastructures and developing rural finance. Finally, we conclude with a summary of main points.