Abstract:

To address the risks posed by compound meteorological disasters, including strong winds, dust storms, and frost, associated with spring cold waves in the Longdong region, this study analyzed data from eight national meteorological stations in Qingyang City. Observations of temperature, precipitation, strong winds, dust, and frost from 1991 to 2024, along with apple phenological data from the Xifeng Agrometeorological Experimental Station since 1994, were utilized. The Climate Trend Coefficient method was applied to quantify warming/cooling rates (calculated via the correlation coefficient between temperature series and time variables, ranging [-1, 1]), and Pearson correlation analysis was employed to examine the relationships between average temperature during the flowering period and fruit set rates, as well as wind speed and pollinator activity frequency. Results indicated that strong wind and cold wave events in spring of 2025 were the most frequent in 34 years, with an extreme gust of 39.5 m/s (Level 13) recorded by the Wugou Regional Station in Zhenyuan County. Wind and dust obstructed bee activities, stripped petals, and desiccated stigmas, reducing fruit set rates in naturally pollinated orchards by 20%-35% compared to normal levels. Benefiting from above-normal precipitation in the summer of 2024 and January 2025, soil moisture storage in the 50-100 cm deep layer remained favorable (55%-70%), buffering the impact of surface drought. Consequently, the yield reduction rate during the flowering period (8%-12%) was significantly lower than that in 2016 and 2023, indicating a comparatively mild impact. Although artificial pollination did not fully offset the disaster effects, it stabilized overall fruit set rates at 45%-55% (normal level: 60%-70%), effectively mitigating the downward trend. In response to "dry-cold" frost, an integrated defense technology of “smoke generation + heating + air disturbance” was innovatively proposed. Validation showed that its effectiveness was significantly higher than that of single measures, providing a replicable technical model for disaster prevention and mitigation in climatically analogous regions.

Key words: Longdong, apple flowering period, types of disaster, disaster characteristics, trend analysis, prevention and control measures