Abstract:

Temporal and spatial variation characteristics of spring maize wind damage at different growth stages were analyzed based on the daily meteorological data of 43 meteorological stations, growth stages of spring maize in 18 agricultural observation stations and the data of wind damage of spring maize in 43 counties in Jilin province from 1971 to 2023. The meteorological grade index at different growth stages of spring maize wind damage was constructed and verified based on precipitation and maximum wind speed, in order to improve the monitoring and evaluation technology of spring maize damage under different wind and rain conditions. The results showed that: (1) the numbers of wind damage in heading-milk maturity of spring maize in Jilin province from 1971 to 2022 was the highest, reaching 61 times, accounting for 41.5% of the whole growth period from 1971 to 2022; the number of spring maize wind damage showed a significant upward trend, with an increase rate of 1.3 times∙10y⁻¹; the number of occurrences in 2010s was the highest, reaching 76 times, accounting for 52.8% of the total number from 1970s to 2010s; the spring maize wind damage mainly occurred in the central and western part and Dunhua of eastern part of Jilin  from 1971 to 2022, which Dunhua had the largest number of occurrences, 10 times. (2) There was a significant positive correlation between the process precipitation of 2 days before and on the day of the occurrence of the wind damage and the percentage of damage area, and the fitting effect was the best, R² was 0.616; the wind damage regression equations of spring maize in different growth stages were established by using the maximum wind speed and process precipitation, each regression equation showed a significant linear positive correlation (P＜0.01), which conformed to the sample independence and had a good fitting effect, R² was greater than 0.5. (3) The jointing−heading stage was most susceptible to less rainfall type wind damage, and the moderate wind damage was most prone to occur; the milk maturity−maturity stage was most susceptible to heavy rainfall type wind damage, and it was most prone to moderate and above wind damage. (4) The disaster grade of typical cases of wind damage in jointing-maturity stage of spring maize based on the meteorological grade index of less rainfall type wind damage and heavy rainfall type wind damage was determined and verified, the proportion of wind damage grade determined by the index completely consistent with the actual situation was 72.7%, and the proportion of one grade different from the actual situation was 18.2%; the accuracy of heavy rainfall type wind damage was higher, and the proportion of complete consistent was 85.7%, the proportion of coincidence in less rainfall type wind damage was 50%. In summary, the meteorological grade index of spring maize wind damage can reasonably determine the degree of wind damage in each growth stage of spring maize under different wind and rain conditions, which can provide reference for disaster prevention and mitigation of local agricultural production.

Key words: Spring maize, Wind damage, Meteorological grade, Maximum wind speed, Process precipitation