Suitability analysis of key potato growth stages in Inner Mongolia under climate change

Inner Mongolia is the main potato planting area in China. It is therefore of practical importance to explore regional suitability of potato in Inner Mongolia under climate change. Based on the climatic suitability model, this paper analyzed the space-time characteristics of climate suitability for potato cultivation in Inner Mongolia using daily meteorological data (average temperature, maximum temperature, minimum temperature, precipitation, sunshine hours, wind speed, relative humidity and atmospheric pressure) from 119 weather stations during the period 1961-2015. This period was divided into two sub-periods (1961-1990 and 1991-2015) to calculate the suitability of climate for potato critical growth period (from flowering to harvesting) and to analyze the spatial and temporal variations of potato climate suitability. The results showed that average climate suitability index of potato growth from flowering to harvesting in 1961-2015 was 0.62, confirming that climatic conditions were suitable for growing potato in Inner Mongolia. The suitability index of sunshine hours was highest and that of precipitation lowest. This further illuminated that light and heat conditions in the region were better than water condition, and water was the main limiting factor of potato cultivation in Inner Mongolia. For the spatial distribution, the trend in temperature suitability tracked a low-high-medium curve from west to east. The suitability of precipitation was better in the southeast than in the northwest. Also the suitability of sunshine hours was high in the west and low in the east. For the comprehensive suitability of climate based on the above three factors, high-value areas were distributed in the east of Yin Mountain and the south of Daxing'anling Mountain regions, while the low-value areas were in the west of Inner Mongolia. Then for the time scale, the paper analyzed the annual changes in climatic suitability. Most of the area showed an uptrend in climate suitability for 1961-1990, except the north-east and north-west of Inner Mongolia. However, there was a significant decline in climate suitability in most of Inner Mongolia during 1991-2015. For the investigated 55 years (1961-2015), there were different climatic trends/indexes in the growth period form flowering to harvesting of potato in different regions, driven by climate change in Inner Mongolia. The comprehensive climatic suitability increased little in the southeast of Yin Mountain, northwest of Yin Mountain, the Hetao Irrigation District and the Alxa League, while other regions showed a decreasing trend. In general, there was a decreasing trend in climate suitability for potato from flowering to harvesting in Inner Mongolia, which occurred at an average rate of 0.004 0·(10a)-1. The suitability of temperature and precipitation declined, while sunshine hour suitability basically flattened, which was not good for potato growth in the region. Therefore, there was the need to strengthen moisture and temperature managements during the period from flowering to harvesting of potato. The results of the study reflected the overall condition for the cultivation of potato in Inner Mongolia and also provided the necessary references for the efficient utilization of climatic factors.