关键词: 水稻, 县域单元, 时空变化, 贡献率, 重心

Abstract:

Rice is one of the most important grain crops in China. To clear spatio-temporal change characteristics of rice in recent decades is of great significance in optimizing the layout of rice and promoting the sustainable development of rice production. This study was conducted to figure out spatio-temporal dynamic changes of national rice production, planting area and yield; to map gravity center migration path of rice production and area based on county data particularly since 1985; and to quantitatively analyze rice production contribution merely caused by area and yield. Variation period was calculated by wavelet analysis using deviations from average of national rice-producing data from 1949 to 2017. Rice-producing gravity centers were computed by ArcGIS using county-level data of rice production and planting area, and then connected them in order of year. Production contribution was firstly divided into three components separately resulted from area, yield and mutual interaction, in that case production changes caused by them could be reckoned to get production contribution rate. ArcGIS was applied to display spatial distribution on the background of two maps including Chinese rice cropping regionalization and provincial administrative division. To come out, the variation periods were respectively 49 years and 21 years, 26 and 60 years of production, area and yield. From 1985 to 2015, nearly 50% of planting region increased in rice production, about 70% decreased in rice planting area, and more than 80% increased their yields. The gravity center of national rice production and planting area migrated northeastwards about 229 km and 225 km. What’s more, the gravity center of the northeast migrated more northeastwards at about 238 km and 242 km. In China, the proportion of yield, as a dominant factor of rice production contribution, fell from 56.3% to 28.3%, and area increased from 34.7% to 63.1%. In conclusion, increasing yield in every rice cropping region, increasing planting area in single cropping region of northeastern and decreasing planting area in double cropping region of South China and single and double cropping region of Central China are main rice distribution characteristics in China. Rational layout of rice planting area and increasing yield are more and more important in stabilizing and enhancing rice production. Rationally using resources, increasing the degree of mechanization and comparative effectiveness are critical pathways to promote Chinese rice production.

Key words: rice, county unit, spatio-temporal changes, contribution, gravity center