Abstract:

To investigate the trends of meteorological elements at different growth stages of maize in Shenyang and their impact on meteorological yield, the Mann-Kendall test was employed to analyze the mean values of four meteorological elements (i.e., air temperature, precipitation, relative humidity, and wind speed) during the sowing, jointing, tasseling-milk, and maturity stages and annual meteorological yield from 2000 to 2021. The impact of climate change on the meteorological yield of maize was studied. Results showed that there was no significant trend in air temperature during the sowing and jointing stages. Before 2017, there was a downward trend during the tasseling-milk stage, followed by an upward trend. Before 2008, there was an upward trend during the maturity stage, followed by a downward trend. Precipitation showed an upward trend during the sowing and tasseling-milk stages, while there was no significant trend during the jointing and maturity stages. The relative humidity showed no significant trend during the sowing stage, while it exhibited an increasing trend during the jointing, tasseling-milk, and maturity stages. The wind speed showed a decreasing trend in all four stages. In years with higher meteorological yields, air temperature and precipitation during the four stages were generally higher, relative humidity was higher during the jointing and tasseling-milk stages, and wind speed was slightly lower during the four stages. In years with lower meteorological yields, air temperatures were slightly lower during the growth stages except the sowing stage, precipitation was excessively high, relative humidity was slightly higher during the tasseling-milk and maturity stages, and wind speed was excessively low. Based on the Pearson correlation coefficient, the main influencing factors selected were precipitation and relative humidity during the sowing stage, wind speed during the jointing stage, precipitation during the tasseling-milk stage, and temperature and wind speed during the maturity stage. Based on the above factors and the random forest algorithm, a meteorological yield prediction model was constructed, which could effectively simulate the trend of meteorological yield. This study can provide the theoretical basis for maize industry management, risk assessment, and agricultural sustainable development in Shenyang.

Key words: maize, growth stages, meteorological elements, Mann-Kendall test, meteorological yield prediction model, Shenyang