西南地区耕地复种指数的时空格局演变及影响因素

The evolution of spatiotemporal patterns and the influencing factors of the multiple cropping index of cultivated land in Southwest China

基于复种指数和“热量-降水”定量化关系模型,分析了西南三省(四川省、贵州省、云南省)从1990—2015年间耕地复种指数的变化趋势、格局演变及其影响因素。结果表明:从1990—2015年云南、贵州和四川复种指数比分别降低27.04%、1.67%和25.83%,复种指数均值分别为147.37%、239.69%和206.05%。2006—2015年为三省粮食作物复种指数波动变化最大的时期,该期粮食作物复种指数年际变动率为四川>贵州>云南,其值分别为-41.01%、-33.55%和-29.60%。西南地区耕地复种指数总体上呈东高西低的空间分布格局,其中东部地区耕地复种指数明显高于西部地区,中部地区高于北部和南部地区。2010—2015年,中国西南地区潜力复种指数均为东部和南部地区高于中部和西北部地区,其中四川东部地区潜力复种指数最大;云南省耕地复种可提升潜力值,明显高于贵州和四川,贵州省可提升潜力地区最少。耕地复种指数年际变化受自然因素和人类活动的影响较大,其中复种指数与年均温度、≥0℃积温、人口数量和农业生产总值呈显著的正相关关系;一般而言,丘陵地区耕地复种指数低于平原地区;气候因子中的温度变化与西南地区复种指数之间的变化呈显著的正相关关系(P<0.01),但温度变化是其变化的关键因子。

Based on the multiple cropping index(MCI)and“heat-precipitation”quantitative relation model,this paper analysed the changing trends and pattern evolution of the MCI from the 1990 to 2015 and its influencing factors.The results indicated that from 1990 to 2015,the MCI values of Yunnan,Guizhou,and Sichuan decreased by 27.04%,1.67%,and 25.83%,respectively.The average values of MCI values were 147.37%,239.69%,and 206.05%,respectively.The greatest change in the three provinces occurred from 2006 to 2015.The inter-annual variations in the grain crop MCIs were ranked as follows:Sichuan>Guizhou>Yunnan,with values of-41.01%,-33.55%and-29.60%,respectively.The MCI in the Southwest China as a whole,the spatial pattern was significantly higher in the Eastern Region than that in the Western Region and higher in the Central Region than in the Northern and Southern Regions.In 2010-2015,in Southwest China,the PMCIs in the Eastern and Southern Regions were higher than those in the Central and Northwestern Regions;among them,the PMCI in Eastern Sichuan was the largest.The PIMCI was significantly higher in Yunnan Province than in Guizhou and Sichuan.Guizhou Province had the least potential area for promotion.The interannual variation of the MCI was greatly affected by natural factors and human activities,among which the MCI had a significant positive correlation with the year average temperature,accumulated temperature≥0℃,population,and gross farm production.The spatial variation in the MCI was closely related to the terrain.Generally,the MCI in the hilly area is lower than that in the plain area;There was a significant positive correlation between the temperature change in the climatic factors and the change in the MCI in the Southwest China(P<0.01),but the temperature change was the key factor affecting the MCI changes.