Abstract: 【Objective】Analyze the characteristics of leaf air temperature difference during the critical water demand period of maize to clarify the main climatic factors affecting maize leaf air temperature in semi-arid sandy areas.【Methods】During maize critical water demand period（July-September）,distributed multi-point leaf temperature continuous measurement experiment was carried out in the field in the maize planting area in Chifeng City,Inner Mongolia. The changing characteristics of leaf temperature and leaf air temperature difference indexes during maize critical water demand period were analyzed. The influence degrees of wind speed,air humidity,rainfall,and soil moisture on the leaf air temperature difference were discovered by correlation analysis to reveal the key influencing climatic factors.【Results】As maize grew and the length of drought duration increased,leaf air temperature change during maize critical water demand period gradually became more drastic,daily leaf air temperature difference increased,leaf temperature difference had an overall upward trend. The overall trend of wind speed gradually decreased. The air humidity was consistent with the process of rainfall changes. Soil moisture decreased with the time progress. The effect of wind speed variation on maize leaf air temperature difference was mainly reflected in sunny days. Wind speed variation had negative correlation with maize leaf air temperature and positive correlation of maize leaf temperature. Air humidity was strongly correlated with both leaf air temperature difference and leaf temperature and was not affected by weather conditions. Rainfall made the fluctuation of leaf air temperature difference became smaller and irregular,but the value of leaf air temperature difference became larger. As the 0-80 cm layer soil moisture storage in maize planting plot gradually decreased,the leaf air temperature difference gradually became larger. The impact of climatic factors on maize leaf air temperature difference during maize critical water demand period were wind speed>air humidity>rainfall>soil moisture.【Conclusion】The leaf air temperature difference showed a fluctuating upward trend during the critical water demand period of maize,and was significantly affected by climatic factors. Wind speed and air humidity were the main climatic driving factors leading to the change of maize leaf air temperature difference.

Key words: Semi-arid sandy area, Maize, Critical water demand period, Leaf air temperature difference