基于EMD模型的我国马铃薯产量波动及其成因的时空研究

TEMPORAL-SPATIAL ANALYSIS OF POTATO YIELD FLUCTUATION AND ITS CAUSES IN CHINA BASED ON EMD MODEL

关键词:  经验模态分解  马铃薯  产量波动  时空研究  产业发展

Key words:  empirical mode decomposition  potato  yield fluctuation  study of time and space  industrial development

摘要:

目的 马铃薯生产是整个产业链的中枢环节，产量的波动对马铃薯产业上下游均有直接影响，对我国马铃薯产量时间序列和时空影响因子进行分析，深入了解我国马铃薯产量波动规律和时空主导因素，有利于指导我国马铃薯产业平稳发展。方法 文章采用经验模态分解模型（EMD）对1982—2018年我国马铃薯总产、单产和面积变化以及不同区域马铃薯产量变化进行分解，对不同时序数据分解后长短周期分量进行波动一致性分析，确定我国马铃薯产量长短周期变化时空主导因子。结果 （1）1982年以来，我国马铃薯总产量整体呈上升趋势，长短波动周期约分别为7年和4年，我国马铃薯生产按时间序列可分为低位缓增期、快速突破期、阶段顶部期、平稳上升期和高位稳定期5个阶段。（2）在时间尺度上，我国马铃薯单产是总产量短周期波动的主控因子，单产和面积分别是1982—2003年和2004—2018年马铃薯产量长周期波动的主控因子。（3）空间尺度而言，北方一作区是我国马铃薯长短周期波动的共同主控区域，西南混作区和中原二作区分别是我国马铃薯长、短周期波动的主控区域。（4）根据我国马铃薯产量分解后分量图形可以预测，在短周期下我国马铃薯产量即将进入下降通道，应该提前做好我国马铃薯总产量下降的战略准备工作，并且通过对短周期波动主控区合理引导种植，避免我国马铃薯总产量短期内出现较大幅度波动。结论 我国马铃薯总产量主要存在长短两种不同时间尺度的周期性波动，单产和面积对总产量长短周期波动的主导作用不同，北方一作区对总产量长短周期波动均具有主导作用，西南混作区在2008年以前对总产量长周期波动的主导作用明显，而中原二作区是总产量短周期波动的主控区域。

Abstract:

Potato production is the central link of the entire industrial chain. Output fluctuations have a direct impact on the upstream and downstream of the potato industry. Analysis of the time series and spatio-temporal influencing factors of my country's potato production is beneficial to gain insights into the laws of potato production fluctuations and dominant factors in time and space the steady development of my country's potato industry.The empirical mode decomposition model (EMD) was used to decompose the total potato output, unit yield and area changes in my country from 1982 to 2018, as well as the changes in potato output in different regions, and the consistency analysis of the long and short period components after different time series data was decomposed. And then the spatiotemporal dominant factors of the cyclical changes of potato production in my country were determined.The results were showed as follows.(1) Since 1982, my country′s total potato production has been on the rise as a whole. The long and short fluctuating periods were about 7 and 4 years respectively. According to the time series, my country′s potato production could be divided into five stages of high stable period, including a low-level slow increase period, a rapid breakthrough period, a stage top period, and a steady rise period. (2) On the time scale, my country's potato yield was the main controlling factor for short-period fluctuations of total output. Yield and area were the main controlling factors for long-period fluctuations of potato production from 1982 to 2003 and 2004 to 2018, respectively. (3) In terms of spatial scale, the northern first cropping area was the common main control area for the long and short period fluctuations of potato in my country, and the southwest mixed cropping area and the Zhongyuan second cropping area were the main control areas for the long and short period fluctuations of potato respectively. (4) According to the decomposed component graph of my country′s potato output, it could be predicted that my country′s potato output was about to enter a decline channel in a short period of time. Strategic preparations for the decline of my country′s total potato output should be made in advance,and the main control area for short-period fluctuations should be reasonable, so as to guide planting to avoid large fluctuations in my country's total potato output in the short term. In summary, the total potato output in my country mainly has periodic fluctuations of two different time scales. Yield and area have different leading effects on the long and short periodic fluctuations of the total output. The first cropping area in the north has a leading role in the long and short periodic fluctuations of the total output, and mixed cropping in the southwest. Before 2008, the region played a leading role in the long-term fluctuations of total output, and the Zhongyuan tow cropping region is the main control region for the short-term fluctuations of total output.