Abstract:

Under the backdrop of global climate change, in-depth investigation into the evolutionary characteristics of climatic resources during the growth period of A. argyi var. qiai is of great practical significance for promoting the scientific layout and sustainable development of its producing areas. Based on the daily meteorological observation data (including daily average temperature, daily maximum temperature, daily minimum temperature, daily precipitation, and sunshine duration) from 1965 to 2024 at Qichun National Basic Meteorological Station, combined with the key phenological periods (February-October) and different growth stages of A. argyi var. qiai, this study comprehensively adopted methods such as linear trend analysis, Mann-Kendall mutation test (combined with sliding T-test), Pearson correlation coefficient for trend testing, and the Miami model, to systematically explore the temporal variation and spatial differentiation characteristics of key climatic resources (i.e., light, heat, and water) during the growth period of A. argyi var. qiai, and evaluate the evolutionary characteristics of climatic potential productivity. The results indicated that:(1) during 1965-2024, the average temperature during the growth period of A. argyi var. qiai increased significantly with a climatic tendency rate of 0.38°C/10 a; the effective accumulated temperature ≥10°C also increased markedly, with a tendency rate of 104.36°C·d/10 a; (2) annual precipitation showed no significant linear trend, with a slight increasing tendency rate of 5.54 mm/10 a; the average annual number of precipitation days was 139.2 days, with no significant long-term trend (tendency rate 0.12 d/10 a), and interannual variability was the main characteristic of its evolution; (3) sunshine hours exhibited a significant decreasing trend overall, with a climate tendency rate of -25.23 h/10 a; (4) the average frost-free period was 257.3 days, showing a significant prolonging trend (tendency rate 6.366 d/10 a, with 91.66% of the years having a frost-free period ≥250 days, which could meet the demand for 2-3 harvests per year; (5) results of the Mann-Kendall trend test and sliding T-test revealed that the impact of climate evolution on the growth of A. argyi var. qiai presented an overall pattern of “significant heat gain and gradually emerging light constraints”; (6) climatic potential productivity increased with rising temperatures, but its exertion was unstable due to the combined constraints of uneven precipitation distribution and reduced sunshine; (7) based on the climatic requirements for the growth of A. argyi var. qiai, three core climatic factors—heat, moisture, and climate productivity—were selected. Five key indicators, namely, active accumulated temperature ≥10℃, precipitation during the growth period, sunshine duration during the growth period, frost-free period, and number of days with high temperature ≥ 35℃, were adopted to construct a comprehensive climatic suitability index (CSI) for the growth period of A. argyi var. qiai. The index was further classified into five grades. The climate suitability index showed that 96.6% of the years were at the “suitable” level, and only 3.4% of the years were “extremely unsuitable” due to extreme climate events (e.g., the drought in 1968). In conclusion, based on the quantitative characteristics of climate evolution during 1965-2024 in Qichun, through the three-dimensional coordination of “resource adaptation-risk prevention and control-potential improvement”, we should fully leverage the advantages of heat gain and frost-free period extension, alleviate the constraints of reduced sunshine and precipitation fluctuation, ensure the sustainable cultivation of genuine A. argyi var. qiai under the background of climate change, and enhance the climatic adaptability of the growth of A. argyi var. qiai.

Key words: long-term series, growth period of Artemisia argyi var. qiai, climatic resources, variation, characteristic analysis