The future of the ecologically fragile areas on the Qinghai-Tibet Plateau (QTP) is a matter of concern. With the implementation of the Western Development Strategy, the Lanzhou-Xining Urban Agglomeration (LXUA) has encountered conflicts and compromises between urban expansion, ecological protection, and farmland protection policies in the rapid development of the past 2 decades. These deeply affect the land use layout, making the ecological sustainable development of the ecologically fragile areas of the QTP a complex and urgent issue. Exploring the impact of different policy-led land use patterns on regional ecosystem services is of great significance for the sustainable development of ecologically fragile areas and the formulation of relevant policies. Following the logical main line of “history-present-future”, the Patch-level Land Use Simulation (PLUS) model, which explores potential factors of historical land use, and the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model were used to construct three future scenarios for the modernization stage in 2031 dominated by different land use policies in this study. These scenarios include the Business-as-Usual Scenario (BS), the Cropland Protection Scenario (CP), and the Ecological Protection Scenario (EP). The study analyzed and predicted land use changes in the LXUA from 2001 to 2031 and assessed carbon storage, habitat quality at different time points, and water yield in 2021. The results indicated that land use changes from 2001 to 2021 reflect the impacts and conflicts among the Western Development Strategy, ecological protection policies, and cropland preservation policies. In 2031, construction land continues to increase under all three scenarios, expanding northwards around Lanzhou, consistent with the actual “northward expansion” trend of Lanzhou City. Changes in other land uses are in line with the directions guided by land use policy. By 2031, carbon storage and habitat quality decline under all scenarios, with the highest values observed in the EP scenario, the lowest carbon storage in the BS scenario, and the lowest habitat quality in the CP scenario. Regarding water yield, the LXUA primarily relies on alpine snowmelt, with construction land overlapping high evapotranspiration areas. Based on the assessment of ecosystem services, urban expansion, delineation of ecological red lines, and improvement of cropland quality in the LXUA were proposed. These findings and recommendations can provide a scientific basis for policy makers and planning managers in the future.

Carbon emissions from crop farming are a critical component of carbon emissions from land use. This study focuses on crop farming in the Yangtze River Economic Belt. The carbon emission coefficient method, the LMDI model, the Tapio decoupling model, and the GM(1,1) gray forecasting model were employed to systematically analyze the spatiotemporal evolution, driving mechanisms, decoupling effects, and future trends of carbon emissions from crop farming in the Yangtze River Economic Belt, based on panel data from 11 provinces (municipalities) covering the period 2013–2024. The results show that the total carbon emissions from crop farming in the Yangtze River Economic Belt exhibit an inverted “U”-shaped pattern, rising initially and then declining, while carbon emission intensity continues to decrease. In terms of emission sources, methane emissions from paddy fields account for the highest proportion, emissions from agricultural inputs show a steady decline, and emissions from soil use continue to rise. Regarding driving factors, crop farming efficiency is the most significant negative driver, while regional economic development serves as the primary positive driver; the decoupling pattern has gradually transitioned from “weak decoupling” to a predominantly “strong decoupling” pattern; projection results indicate that both carbon emissions and emission intensity from crop farming in the Yangtze River Economic Belt will generally decline in the future, though regional pressure for emission reductions remains significant; agricultural industrial structures should be optimized and adjusted, with efforts focused on promoting the standardized and scaled development of organic and ecological agriculture to facilitate the green and low-carbon transformation of agriculture.