中国生猪耗粮系数时空演变特征

当代中国,生猪饲料粮的生产与消费已经逐渐成为影响我国粮食安全保障的重要问题。耗粮系数是合理测算饲料粮需求量的核心,厘清其时空演变特征对准确测算饲料粮数量具有重要意义。通过着重测算2000—2018年中国不同规模饲养生猪耗粮系数,探讨其时空演变特征及可能原因,得到以下主要结论：（1）近年来我国生猪耗粮系数呈现出明显的上升趋势,由2000年的2.39上升至2018年的2.76,年均增长0.023。（2）不同规模饲养生猪耗粮系数的差距逐渐缩小,主要受到饲养过程中使用的精饲料占比变化趋同的影响。（3）大规模饲养生猪的粮食转化效率和时间效率均高于其他规模。（4）散养生猪的耗粮系数在空间上呈现“南北高,中部低”,其他规模则呈现“北高南低,中部高东西低”的格局。从提高粮食利用效率的角度,我国生猪养殖宜继续推动大规模饲养。

Spatial and temporal variations of grain consumption coefficient of pig in China

The production and consumption of pig feed grain have gradually become the primary factor affecting China's food security. The grain consumption coefficient, which is easily influenced by the natural environment and economic conditions, is the core of reasonable estimation of feed grain demand. Therefore, it is important to clarify the spatial and temporal variation characteristics. Accordingly, taking pigs as an example, we measured the spatial and temporal variations of the grain consumption coefficient and the possible causes of different feeding scales in different provinces from 2000 to 2018. The conclusions can be drawn as follows: (1) The grain consumption coefficients of a backyard, small-scale, and the average value of all the scales showed an increasing trend while those of the medium and large scales showed a decreasing and then an increasing trend. (2) The gap between the grain consumption coefficients of different scales was narrowed gradually with the decreasing percentage of concentrated feed costs. (3) The grain conversion efficiency and time efficiency of a large scale were higher than those of other scales. (4) Except for backyard feeding, the grain consumption coefficients of other scales were higher in northern China and lower in southern China while those of the central region of China were higher than the eastern and western regions. The high grain conversion coefficient of consumption in northern China may be due to the fact that pigs need more energy to protect themselves from cold and need to consume more feed, while the differences in southern China may be related to the breed and feed type composition of the pigs. In addition, in order to improve efficiency and save food, it is significant to promote the large-scale pig feeding pattern, to standardize, intensify, mechanize and automate the construction of pig rearing, and to improve the efficiency of pig breeding. Large-scale farming should be distributed in Xinjiang, Qinghai, Sichuan, Guangxi, Hebei, Shandong, and Henan, and over-farming is not recommended in the northeast region as well as Hubei and Hunan. Provinces in the central region, such as Sichuan, Shaanxi, Guizhou, and Hunan, are appropriate for backyard pig farming. To improve feed utilization efficiency, it is advisable to promote large-scale pig breeding.