Abstract:

This study aims to investigate the spatiotemporal evolution of meteorological conditions and disaster risks during different growth periods of sorghum in the Zunyi region, and to assess the comprehensive meteorological risk. Based on data from 12 national meteorological stations in Zunyi from 1981 to 2024, methods including linear trend analysis, Mann-Kendall (M-K) mutation test, and entropy weight method were employed. The spatiotemporal evolution characteristics of meteorological conditions and major disaster risks (late spring cold/high temperature, drought, cloudy-rainy weather) during the sorghum nursery period, growth period, early maturation period, and late maturation period were systematically analyzed, followed by a comprehensive risk assessment. The main conclusions are as follows. (1) From 1981 to 2024, temperatures during all sorghum growth periods in Zunyi generally increased, with the most significant warming during the nursery period (0.7 ℃/10a, P<0.01). Precipitation exhibited a pattern of “increase in early stages, decrease in later stages”, with the largest decrease in the late maturation period (-8.6 mm/10a). Sunshine duration showed fluctuating changes, increasing during the nursery period and decreasing during the growth period. Concentrated mutations in meteorological elements occurred around 2000 and 2010, with temperatures generally rising by 0.3-1.8℃ after the mutations. (2) Disaster risks displayed a transition characteristic of “decreasing low-temperature risk and increasing high-temperature risk”. The number of late spring cold days during the nursery period decreased significantly (-1.3 d/10a, P<0.01), while the number of high-temperature days from the growth period to the late maturation period all increased significantly (0.1-1.1 d/10a). (3) Dominant risks varied significantly across different growth periods. Late spring cold was the core risk during the nursery period (weight 51.7%). During the growth period, early maturation period, and late maturation period, overcast, rainy and low-light weather became the dominant risk (weights 36.2%-39.9%), with high temperature and drought having similar weights (29.8%-32.4%). The northern and eastern parts of the region exhibited higher risks during the nursery period (≥0.8). Chishui City was identified as the area with the most prominent meteorological risks during the middle and late growth periods (≥0.6-0.8). The sorghum production in Zunyi exhibits a spatiotemporal differentiation pattern characterized by “late spring cold days in the early stage, and superimposed overcast, rainy and lowlight weather with high temperature and drought in the middle and late stages,” necessitating precision defense measures tailored to growth stage, region, and disaster type.

Key words: sorghum, reproductive period, comprehensive meteorological risk, entropy weight method, mutation test, trend analysis