Abstract:

Based on the long-term monthly temperature archives data of Suolon Meteorological Station in the past 68 years (1958-2025), this study systematically reveals the temporal evolution characteristics of agricultural thermal resources in the southern foothills of the Greater Khingan Mountains and their driving mechanisms on cropping systems. The results indicated that over the past 68 years, agricultural thermal resources in Suolun had shown a significant optimization trend, with a climate warming rate of 0.3℃ per decade (P<0.01) during the growing season (May-September), an accumulated active temperature increase of 150-200℃·d, and a warming rate significantly higher than global and national averages. The thermal resource evolution exhibited distinct three-phase characteristics: a slight decline (-0.1℃ per decade) from 1958-1985 (baseline period), a rapid warming surge (1.1℃ per decade) from 1986-2005 (transition period), and a recent high-fluctuation phase (0.1℃ per decade) from 2006-2025, with the mid-late 1990s serving as a critical turning point (sliding t-test t=5.314, P<0.01) that fundamentally transformed cropping systems. Seasonal differences were pronounced, with the highest warming rate in spring (0.481℃ per decade), directly influencing earlier sowing dates and seedling growth. Agricultural climate potential had significantly improved, with accumulated active temperatures rising from the "relatively suitable" range (2240.5-2562.7℃·d) in 1958-1985 to the "suitable" range (2365.1-2790.7℃·d) in 1986-2005, and further approaching the threshold for mid-late maturing varieties (≥2750℃·d) in 2006-2025. Agricultural suitability zones had shifted significantly northward, with corn planting proportions increasing from less than 20% before 1985 to over 50% in the 1990s, and cropping systems transitioning from wheat-dominated to corn-dominated. Recommendations include advancing the sowing period from the traditional early May to late April, establishing a dynamic zoning mechanism updated every five years, enhancing meteorological archive digitization, and fully leveraging the strategic support value of long-term meteorological records in smart agriculture and rural revitalization.

Key words: meteorological archives, agro-climatic resources, growing season accumulated temperature, climate tendency rate, cropping system