Background Arable land serves multiple functions, including food security, ecological conservation, and social security. To explore the misalignment between these multiple functions and its extent, we constructed an evaluation index system that includes landscape ecological function, socioeconomic function, and production security function based on data from 277 county units in the mountainous agricultural region of Southwest China from 2010 to 2021.

Methods The entropy weight method was used to synthesize the functional indices of arable land. The spatial misalignment index (SMI) was used to quantify the degree of inconsistency between the multifunctional aspects of arable land. The obstacle degree model and geographic detector were used to analyze the driving mechanisms.

Results 1) In terms of temporal characteristics, from 2010 to 2021, the multifunctionality of arable land in the southwestern mountainous agricultural region was mainly positively misalignment, presenting a clustered pattern. The proportion of counties with positive misalignment increased from 89.531% (248 counties) in 2010 to 92.780% (257 counties). The number of counties with low positive misalignment showed an overall trend of first decreasing and then increasing, while the number of counties with moderate positive misalignment first increased and then decreased. The number of counties with high positive misalignment and low negative misalignment remained relatively stable, while the number of counties with moderate negative misalignment decreased overall. 2) In terms of spatial differences, the distribution of high positive misalignment zones highly correlated with the distribution of karst topography. In these areas, ecological function lag issues are significant due to terrain fragmentation and economic development pressure. Counties with negative misalignment were concentrated in the central and southern parts of the study area. Additionally, in terms of sub-regional differences, sub-region II has no counties in negative misalignment, and the number of counties in moderate positive misalignment has decreased by 38.889% (14 counties). Sub-region III and VI have no counties in high positive misalignment, and Sub-region VI has seen a decrease in moderate positive misalignment counties and an increase in low positive misalignment counties. The number of counties in Sub-region IV with positive moderate misalignment increased to 36, representing a 33.333% increase. 3) In terms of driving mechanisms, socio-economic functions are the primary internal driving factors of multifunctional spatial misalignment in arable land (0.174). The contribution rate of agricultural value added (28.849%) and grain yield ratio (23.198%) are key obstacle factors requiring attention, with the highest contribution levels observed in Sub-region II and Sub-region V. In terms of external driving factors, nighttime lighting data, sunshine hours, distance from prefecture-level cities, air temperature, and relative humidity are the primary driving factors of spatial misalignment, and there are nonlinear enhancement or two-factor enhancement interaction effects among these factors. The interaction between temperature and per capita public fiscal budget revenue exhibits the strongest driving effect.

Conclusions This paper reveals the evolving characteristics and driving factors of the unbalanced synergistic development of the “landscape ecology-socioeconomic-production security” functions in the southwestern mountainous region, and suggests implementing differentiated zoning management, strengthening agricultural intelligence and supply-side reforms to enhance comprehensive benefits, improve agricultural product quality, promote rural economic transformation and upgrading, and facilitate the multifunctional synergistic sustainable development of arable land.