Fluctuation characteristics of grain output in He'nan based on EMD model

Aimed to provide basis for continuous and steady growth in grain output of He'nan, the empirical mode decomposition method and variance decomposition method are comprehensively applied in the paper, and the fluctuation characteristics of grain output in He'nan from 1985 to 2013 are systematically analyzed at different scales. It is indicated from results that: 1. at the provincial scale, change in grain output in He'nan is mainly based on trend growth, and there is the quasi-periodic fluctuation of about 4 years. 2. In the second-level area of the farming system, change in grain output in Huanghuai plain terrain, Hebei-Shangdong-He'nan low-lying plain region and Yanshan-Taihang mountains piedmont plain is mainly based on trend growth, and fluctuation of grain output in hilly area at western He'nan is relatively intense. The influence of grain output in Huang-Huai-Hai plain terrain and Hubei-Henan-Anhui hilly and mountainous region is remarkable on fluctuation in grain output in He'nan. 3. At the county-level scale, the county-level grain output is mainly contained 2 or 3 fluctuation components. The change in county-level grain output is mainly based on variation tendency, and the counties that with the variance contribution rate of grain trend over 85%, the northern part of Yanshan-Taihang mountains piedmont plain and the northern part of Huang-Huai plain terrain. Fluctuation in grain output has the distribution pattern of “high in the southeast and low in the northwest”.