Abstract:

To enhance the utilization rate of climatic resources during the growth season of early rice in Zhejiang Province and to achieve sustained and increased yields, daily average temperature, precipitation, and sunlight data from 66 national meteorological stations in Zhejiang Province spanning from 1971 to 2022 were analyzed in this study. Utilizing methods such as linear trend analysis and Mann-Kendall (M-K) test, the spatial-temporal variation characteristics of heat, precipitation, and light resources during the early rice growing period and growing season over the past 52 years were examined. The results indicate that the average temperature during the early rice growing period and growing season exhibits a distribution pattern characterized by higher values in the southwest and lower values in the northeast. The climate tendency rate fluctuates with increase of 0.34℃/10a and 0.38℃/10a for average temperature for heat accumulation, with a significant increase point observed in 2002. The annual accumulated temperature above10℃ for early rice ranges between 2719.1 to 3286.4℃·d, also displaying a southwest-high/northeast-low gradient with an increasing climate trend of 75.8°C·d/10a; notably, northeastern regions exhibit a faster increase compared to southwestern areas, leading to a reduction in spatial disparities regarding thermal resources. Interannual variability is significant for precipitation resources; their spatial distribution decreases progressively from southwest to northeast with marked differences observed across regions. The climate trends for precipitation during both the early rice growing period and overall growth season show slow increases at rates of approximately 12.2mm/10a and 14.1mm/10a respectively; these trends follow a staircase-like distribution where northeastern areas are wetter than southwestern ones. Light resource availability demonstrates considerable interannual fluctuations as well, and sunshine resources also exhibit large interannual variations with average sunshine hours being 698.9h and 771.9h, respectively, both showing declines at rates of -11.2h/10a and -8.9h/10a.The research findings provide meteorological evidence and support for enhancing the utilization of climate resources, mitigating meteorological disasters, and implementing scientifically informed varietal distribution, and help to achieve a sustained increase in early rice production in the Zhejiang region.

Key words: agricultural climate resources, early rice growing season, Zhejiang, precipitation, sunshine hours, climate warming, planting system, spatiotemporal analysis