中国主要粮食作物产后损失特征及减损潜力研究

Main grain crop postharvest losses and its reducing potential in China

为减少作物产后损失,增加粮食供应数量。该文基于物质流分析方法以及农产品流动特征,建立了一套量化作物产后损失的计算方法,在已有数据基础上,重点分析了2010年中国三大粮食作物(水稻、小麦和玉米)产后(包括收获、运输、干燥和储藏)损失特征及其减损潜力。结果显示,中国作物产后损失率较高,水稻、小麦和玉米产后综合损失率分别为6.9%、7.8%和9.0%,三者平均损失率7.9%,高于发达国家作物产后损失水平。粮食产后损失中,储藏环节损失比重最高,损失比例达到40.3%,其次是收获环节,为31.4%,运输和干燥环节损失较小,分别为11.1%和17.2%。农户储藏和收获是作物产后减损的重点环节。情景分析结果显示,通过改进产后不同环节技术条件,可以有效减少作物产后损失,情景5(粮食产后环节技术条件达到最优)三大粮食作物产后损失率均可以降低到4.0%以下。由此可见,中国粮食作物产后减损存在较大潜力,减损重点应落在农户储粮环节以及作物收获环节。作物产后减损需要国家农业科技政策作保障,通过提升农户科学储粮意识以及提高作物机械收获水平和改进作物收获质量等综合措施,最终实现中国粮食作物产后损失的降低。研究结果为中国粮食产后减损政策和措施的制定及实施提供借鉴。

Recently, there is a growing global concern over food loss and waste and its impacts on resources and environment, especially in the developing countries. And it is estimated that about one third of food output worldwide was lost and wasted each year, which has been consistently recognized to be another threat to global and regional food security. Therefore, in addition to maximizing crop yields to enhance food security, reducing food loss and waste from food system is considered as another key strategy to combat hunger and sustainably provide food for the world. However, knowledge about food loss and waste is entirely inadequate worldwide, especially in developing countries including China. Therefore, it is urgent to conduct researches on food loss and waste in different regions in order to comprehensively evaluate global food security situation. In this research, based on the researches available and the data collected from CNKI（China National Knowledge Infrastructure） and other literature database, a method was built and developed to quantify crop postharvest losses, despite the uncertainties due to data limitation. Rice, wheat and maize were chosen as the major crops to be analyzed. Crop postharvest segment was divided into 4 sections, including crop harvest, transport, drying and storage, and each section had different loss ways or loss based on different technology or from agricultural machine, in which crop harvest was divided into combine harvesting and two-stage harvesting, transport was divided into package and bulk transporting, drying was divided into air and mechanical drying, and storage was divided into household and depot storage, and correspondingly the data were classified. With the method presented in this research, a comparative analysis of postharvest losses from the major crops in China was carried out. The results showed that there was a much higher total crop postharvest loss（CPHL） ratio in China compared with the developed countries, the CPHL ratios were 6.9% for rice, 7.8% for wheat and 9.0% for maize, respectively, and the total average CPHL value was 7.9%. Moreover, for the CPHL ratio, the section of crop storage had the largest contribution compared with other sections of crop postharvest segment, and the proportion reached 40.3% in the total crop losses. The second was from the section of crop harvest, with the proportion achieving to 31.4%, and the sections from crop transport and drying had the minimum losses, which were 11.1% and 17.2%, respectively. In addition, household grain storage and crop two-stage harvesting were the most serious loss ways. And based on the different scenarios of crop loss reduction, an evaluation was performed for the year of 2010. The different scenarios indicated that by improving agricultural technical conditions from different sections of crop postharvest, the CPHL ratio could be effectively reduced, and the optimal scenario could cut down CPHL ratio to be less than 4%. So, there is a large CPHL reduction potential existing in Chinese crop postharvest sections. However, to achieve the CPHL reduction, the policies of agricultural science and technology made by the Chinese government, have to play an important role in the comprehensive measures such as raising farmers＇ consciousness of scientific grain storage, promoting mechanization levels of crop harvest and improving crop harvest quality.