我国大豆种植时空分布与风险费率研究

目的]在我国大豆种植锐减、进口攀升和自然灾害加重的背景下,摸清我国大豆种植时空分布特征、风险费率对制定大豆种植和保险政策,保障大豆粮食安全有重要意义。方法]文章依据1978—2016年全国省级大豆播种面积、产量、单产及进口等数据,基于风险损失和产量分布模型,运用数理统计、直线滑动平均模拟法和单产分布模型模拟推导法,分析全国大豆种植的时空分布变化,评估相应的生产风险并厘定各地大豆农业保险费率。结果] 1978—2016年我国大部分省份都有大豆种植,1998年后,仅青海未种植大豆,东北和黄淮海地区一直是我国大豆主产区。2005年全国大豆达到最大播种面积959万hm~2,随后锐减,2015年仅为2005年的67.8%;产量变化趋势和面积变化趋势一致;平均单产为1 153 kg/hm~2,呈现出上升趋势。大豆进口逐年增加,2016年大豆进口总量8 391万t,创历史新高。全国大豆发生灾害风险的平均频率为27.24%,西藏、宁夏、陕西发生灾害风险的频率较高,各地呈现出轻灾(18.24%)中灾(5.74%)重灾(1.95%)巨灾(1.30%)的特征。全国大豆种植的平均费率为4.40%,陕西、河南、安徽、辽宁、吉林和内蒙古大豆种植大省的费率较高,而黑龙江大豆种植的费率则较低,为3.72%。结论]我国大豆种植结构需要调整,在大豆种植大省,如陕西、河南、安徽等,降低种植面积;在保持黑龙江大豆种植优势的同时,发展河北、山东等低风险地区的大豆种植;在开展大豆农业保险时,实行地区差异化费率。

STUDY OF SPATIAL-TEMPORAL DISTRIBUTION AND PREMIUM RATE OF SOYBEANS IN CHINA

This study aims to examine the spatial-temporal distribution characteristics of soybean farming and the premium rate for soybean farming in China. Insurance policies are extremely important for soybean farming, which has been experiencing a sharp decrease in recent years as a result of multiple factors'' functioning especially the large amount of soybean import and natural disasters in China. The methods of statistical analysis, linear sliding average, and yield distribution models were used to investigate the spatial-temporal variations, the risk and premium rate of soybeans in China based on the data of soybean farming area, yield, and import of China from 1978 to 2016. All provinces except Qinhai had planted soybeans since 1998. The Northeast and Huang-Huai-Hai had been being the main production areas. The soybean farming area reached a maximum of 9.59 million hm² in 2005, then continuously declined over year. In 2015, the soybean farming area was only 67.8% of that in 2005. The variation of total yield of soybean coincided that of farming area. The average unit yield was 1 153 kg/ hm² and showed an increasing trend. The import of soybean increased and reached a high level record in 2016 with 83.91 million tons. The average frequency of soybean disasters was 27.24%, while Xizang, Ningxia, and Shaanxi suffered from the disasters more frequently. In most regions, the risk of various degrees of disasters followed the same order of light disaster (18.24%) >medium disaster (5.74%) >severe disaster (1.95%) >extreme disaster (1.30%). The average premium rate of soybean was 4.40%, Shaanxi, Henan, Anhui, Jilin, and Inner Mongolia exhibited the higher rates while Heilongjiang exhibited a lower rate. It concludes that the soybean faming structure needs to be adjusted. Heilongjiang could remain as the major farming area, while the farming area should be reduced in provinces of large soybean farming area with high disaster risk, such as Shaanxi, Henan, and Anhui. In provinces with lower disaster risk, such as Hebei and Shandong, the farming area could be promoted. Different regional rates are suggested to be adopted for soybean planting insurance.