关键词: 桑树, 干旱, 标准化降水蒸散指数, 时空演变, 生育期

Abstract:

Revealing the temporal and spatial evolution patterns of drought during different growth stages of mulberry trees in Guangxi has practical significance for guiding drought-resistant cultivation and ensuring the security of the industry. Daily temperature and precipitation datasets covering Guangxi from 1961 to 2025 were utilized in this study, and the Standardized Precipitation Evapotranspiration Index (SPEI) was selected as the drought evaluation indicator, to investigate the spatiotemporal drought characteristics in different growth stages of mulberry in Guangxi using linear trend analysis, wavelet analysis and spatial interpolation methods. The main results are summarized as follows: (1) Interannual fluctuations were identified as the dominant variation characteristics of SPEI for all mulberry growth stages during 1961-2025, and no significant linear trends were detected. The significant short cycles of 2-4 years were captured during the germination and leaf expansion stages, and the significant short cycles of 3-4 years and 7 years were observed during the vigorous growth stage, the significant short cycles of 3 years and 5-6 years were found during the defoliation and dormancy stage. None of the global dominant cycles of each growth stage passed the significance test at the 0.05 level, which indicated that the drought evolution was dominated by significant short-period oscillations. (2) Light drought was verified as the primary drought type restricting mulberry production at all growth stages in Guangxi. The occurrence frequencies of moderate, severe and extreme drought decreased successively. The highest drought frequency was detected during the germination stage, with widespread light drought across the whole study area. Northwestern Guangxi was identified as the core high-frequency zone of light drought, and moderate drought presented a zonal high-value pattern across the central Guangxi. High-frequency areas of light drought were mainly distributed in eastern and western Guangxi during the leaf expansion stage, while high-incidence regions of moderate drought were shifted to northern, central and southeastern Guangxi. The maximum water consumption was required for mulberry during the vigorous growth stage, yet the spatial distribution of drought was relatively uniform, and local severe drought with certain frequencies was only prone to occur in central and eastern Guangxi. High-incidence zones of light drought were concentrated in central and eastern Guangxi during the defoliation and dormancy stage, and moderate drought exhibited an obvious spatial pattern with higher frequency in western Guangxi and lower frequency in eastern Guangxi.

Key words: mulberry, drought, SPEI, spatiotemporal evolution, growth period