基于LMDI模型的中国粮食产量变化及作物构成分解研究

理清1980-2010 年间中国粮食产量变化的作物贡献及其主要贡献因子,为今后农业政策的调整提供决策依据。论文采用对数平均迪氏分解模型(LMDI)开展1980-2010 年间中国粮食产量变化及作物构成分解研究。研究结果表明:①30 a 间中国粮食产量增加了2.26×10⁸ t,粮食播种面积效应和粮食单产效应分别为-0.21×10⁸和2.47×10⁸ t;粮食单产水平提升对粮食增加量的贡献值大,但这一贡献效应的增加量在减弱。②稻谷、小麦和玉米三种作物产量在全国粮食总产量中的比例波动性上升;稻谷单产、小麦单产、玉米单产,以及玉米播种面积的增产效应最为明显,是驱动全国粮食产量增加的主要因素。③地区贡献以黑龙江和河南最为突出,累积贡献率约占1/3,省域粮食生产“北进中移”的趋势明显;各省域粮食产量的贡献因素差异显著,大豆、薯类和其他作物对粮食总产量变化的贡献较小。建议实施差别化的粮食生产政策,在继续提高粮食单产的同时稳定粮食播种面积,确保国家粮食安全。

Investigating Contribution Factors to China's Grain Output Increase Based on LMDI Model During the Period 1980 to 2010

Identifying the characteristics and the prominent factors of grain output change is helpful to make specific policies for upgrading grain production capacity. Based on the statistical data of grain output and grain sowing area, the logarithmic mean weigh division index method (LMDI) and decomposition model were adopted to reveal the structural characteristics and the influencing factors of variation of China's grain output during the period between 1980 and 2010. The results showed that: 1) The total grain output of China increased by 2.26×10⁸ t from 1980 to 2010. It was estimated that the accumulated contribution of grain sowing area and grain yield per hectare at national scale were -0.21×10⁸ t and 2.47×10⁸ t, respectively. Grain yield per hectare was the major contributing factor for the increment of total grain production. 2) The proportion of rice, wheat and corn in total grain output showed obvious increasing trend and the percentage rose from 80.39% to 89.33%, accounting for 102.01% of the total increment between the years 1980-2010. At the national scale, rice yield per hectare, wheat yield per hectare, corn yield per hectare and corn sowing area were the top four contributing factors for grain output increase. For the effect of grain yield per hectare, each crop had the positive impact during 1980 to 2010, and rice yield per hectare played a prominent role in the total grain increment (accounting for 34.42%), followed by wheat yield per hectare and corn yield per hectare. For the effect of grain sowing area, corn sowing area had the most significant positive effect, while rice sowing area, other crop sowing area and wheat sowing area had the obvious negative effect. 3) There was significantly spatial difference for each contributing factor of grain output increase at the provincial scale. Heilongjiang and Henan were the largest contributing provinces, whose cumulative contribution rate reached up to 30.27%. The major grain producing areas were moving to the northeast and central regions of China. The rapid growth of rice yield per hectare lead to steady rise of rice production in the south, while the superposition of rice yield per hectare and rice sowing area enhanced the total rice output rapidly in Heilongjiang province; the coupling of wheat sowing area and wheat yield per hectare further highlighted the comparative advantage of wheat production in Huang- Huai- Hai region; the combined effect that the expansion of corn sowing area and the growth of corn yield per hectare contributed to the evident increase of rice production in Huang-Huai-Hai region and Northeast region in China. The production advantage areas of wheat, corn and rice were gradually established. However, the output of soybean, potato and other crops increased slowly, and has not yet formed a clear advantage area. The paper concluded that, in addition to improving grain yield, stabilizing the grain sown areas was another important strategy to further stabilize and increase grain production capacity.