Abstract:

This study aimed to mitigate or prevent the adverse effects of heat damage on yield of single-season rice in Xuancheng, ensuring stable rice production in the region. Using meteorological data from seven meteorological stations (1961-2023) and rice yield data (2000-2023) in Xuancheng, the spatiotemporal distribution, variation patterns, and yield impacts of heat damage during the critical growth stages of single-season rice (booting to heading-flowering stages) were analyzed through yield modeling and wavelet analysis. The findings revealed that: (1) total heat damage events increased after the 1990s. After 2000, mild, severe, and extreme heat damage showed rising trends, while moderate damage declined gradually. Mild events were most frequent, followed by severe and moderate, with extreme events being the least common. (2) The spatial extent of heat damage followed the order: mild > severe > moderate > extreme. (3) Heat damage was more prevalent in the southwest and less frequent in the northeast. Ningguo experienced the highest frequency, while Guangde had the relatively lower frequency, with an overall increasing trend. (4) A 4-5 year inverse-phase resonance cycle existed between rice yields and heat damage in Xuancheng, becoming more pronounced after 2007. There was a significant positive correlation between the intensity of high temperature heat damage and the yield reduction of single-season rice. Recommendations include: promoting high-temperature-tolerant indica rice varieties paired with emergency measures like “deep-water irrigation + foliar salicylic acid application” in southern high-risk zones; optimizing sowing dates in northeastern low-risk zones to avoid critical flowering stages from late July to early September. The research results, combined with the above targeted measures, can provide scientific basis and technical support for the stable and high yield of local rice and the enhancement of climate resilience.

Key words: heat damage, single-season rice, wavelet analysis, relative meteorological yield, Xuancheng