Impacts of climate change on the regionalization of spring wheat planting in agro-pastoral ecotone of Gansu Province, China

Climatic factors have posed a great challenge to grain growth in agricultural production, particularly in the arid areas. This study aims to investigate the impacts of climate change on the spring-wheat planning in the ecotone region of northern China. Air precipitation and temperature time series datasets were obtained from 30 meteorological stations in the study area over the past 50 years. The BP neural network was employed to interpolate the irregular and missing data in the time series data. Annual average temperature, annual average precipitation, and the accumulated temperature above 0℃ were selected as the agricultural zoning indicators for the regionalization of spring-wheat planting. The linear propensity rate method, cumulative anomaly method, and Mann-Kendall mutation test were employed to examine the temporal variation and mutation test of the three zoning indicators. Additionally, ArcGIS technology was utilized to perform the spatial analysis of the zoning indicators. The experimental results demonstrated that the annual average temperature was registered at 6.84 ℃, indicating a distinct warming trend characterized by an annual increase rate of approximately 0.56 ℃/10 a. Furthermore, a significant abrupt change was observed in 1998. The annual precipitation displayed a subtle upward trend of 6.10 mm/10 a, marked by a sudden shift in 1980. Lastly, the accumulated temperature above 0℃ manifested a significant warming trend at a rate of 155.41℃/10 a, without any abrupt changes. In spatial distribution, the accumulated temperature above 0 ℃ and the annual mean temperature showed a spatial pattern of low temperature in western regions and high temperature in the rest, while their tendency rate showed a gradually increasing trend from west to east and from north to south. The annual precipitation showed a decreasing spatial distribution pattern from south to north, while their tendency rate was an increasing trend from south to north. The cultivated area of spring wheat in the agropastoral ecotone increased by 565 m, as the climate changed. There was a notable expansion of the suitable planting area in the south and west. There was an increase in a total area of 1.66×10⁶ hm², and an increase of 8.10×10⁴ hm² since 1998, accounting for 5.06% of the total cultivated land. Notably, there was the most significant growth of the spring wheat in the most suitable area for planting, expanding by 24.44 percentage pints. Meanwhile, there were significant disparities in the regional distribution of spring wheat planting. The cultivated land area in the most suitable region for the spring wheat planting within the Gansu agropastoral ecotone expanded by 4.18×10⁵ hm² post-1998, while the suitable area contracted by 2.20×10⁵ hm², and the sub-suitable area diminished by 1.17×10⁵ hm². However, the unsuitable area has experienced a reduction of 6.80×10⁴ hm². The findings of this study can provide a scientific foundation for optimizing and adjusting the spring wheat planting structure in the agro-pastoral ecotone of Gansu province, considering the backdrop of climate change. Moreover, they contribute to regional decision-making and formulation of strategies for rational utilization of climatic resources, thereby promoting sustainable agricultural development as well as enhancing both yield and quality of spring wheat in the agro-pastoral ecotone of Gansu Province.