Study on climatic suitability for planting and effect of crop planting activities on climatic suitability: a case study of Yanting County,Sichuan Province,China
The analysis of crop planting development in Yanting County,Sichuan Province,China from 1950 to 2012 identified a period of relatively stable rural social and economic conditions in the last 32 years (19812012),which interval was selected as a research period. Five types of crops including rice,sweet potato,corn,wheat,and rape were chosen as research crops. Light,heat,precipitation,and other climate parameters were recorded during the growth period of these five crops to estimate resource suitability indices,effective suitability indices,and utilization indices for these crops using a method of agro-climatic suitability. To establish a climatic suitability model for crop planting and an estimation model of the degree to which planting activities affect the planting climatic suitability in a small-scale region,the climatic suitability for planting and the impact of planting activities on climatic suitability for crop planting were estimated for Yanting County,and selected as a model for a small-scale region,in the last 32 years. The adaptations of regional crop planting activities on climate change were primarily discussed. The following results were obtained. (1) The average resource suitability index,effective suitability index,and utilization index for spring crops (0.578,0.281,and 48.37%, respectively) were higher than those for autumn crops (0.304,0.128,and 42.24%,respectively). Significant differences were observed among climatic suitability indices for the five main crops,and climatic suitability degree for spring crops was higher than that for fall crops. (2) Significant inter-annual fluctuations in the degree of crop climatic suitability in Yanting County were caused by the monsoon climate. There was an insignificant negative effect of climate change on the degree of climatic suitability for spring crops,and a limited positive effect on that for fall crops during the last 32 years. (3) The average resource suitability index,effective suitability index,and utilization index for crop planting in Yanting County over the last 32 years were 0.466,0.212,and 45.49%,respectively. As a result of inter-annual fluctuation of the resource suitability index,effective suitability index,sowing area,and yield of the five crops,the degree of climatic suitability for crop planting fluctuated significantly in the county during the study period. Climate change had a negative effect on the degree of climatic suitability for planting. (4) The average degree to which crop planting activities affected the extent of climatic suitability for planting was 0.00092 in the study period and it was variable. Crop planting activities can alter the degree of climatic suitability for planting by adjusting the combination of planted crops. A slight positive impact of crop planting activities on the degree of climatic suitability for planting in the county was identified before the middle of the 1990 s,indicating that there was a slight adaptation to climate change during this period. A negative influence of crop planting activities on the degree of climatic suitability for planting in the county was observed after the middle of the 1990 s.