The Northeast Farming-pastoral ecotone (NFPE) in China is crucial for farming and pastoralism. However, sustainable development of land resources faces several challenges from human activities and environmental degradation. Thus, assessing land resource-carrying capacity (LRCC) is crucial for effective land-use planning and management. This study proposes a comprehensive indicator system to evaluate LRCC in the NFPE. We integrate remote sensing, model simulation, and statistical data, employing Geographic Information System analysis and statistical techniques to assess spatiotemporal evolution characteristics of LRCC. Findings indicate increasing LRCC with spatial-temporal heterogeneity. The northern region exhibits relatively high and growing LRCC, while some eastern regions have low LRCC but a high growth trend. The southern region displays both low LRCC and growth. Balancing regional development and ecological protection requires considering spatial heterogeneity of LRCC in land-use planning and management decisions, facilitating differentiated land-use strategies for sustainable development.

As an important means of production and habitation, land is the core natural resource for people’s life and production. However, the escalating demand for land resources, along with population growth, has created a pressing challenge at the intersection of land, population, and grain. In this study, we used a combination of temporal and spatial perspectives, along with spatial analysis methods, to analyze the supply and demand of land resources in the Northeast Farming–Pastoral Ecotone (NFPE) based on the population–grain relationship. The results show that the carrying capacity of land resources in this region increased gradually and the number of people it can carry increased from 34.23 million (2000) to 127.96 million (2018). From 2000 to 2018, the land resource carrying index (LRCI) was greater than 1.125, showing a state of surplus in grain, and the LRCI increased by 0.23 per year. Most areas in this region are in a state of grain surplus, with 13 counties showing a population and grain balance, and 2 counties being overpopulated. However, the increasing trend of land resource carrying capacity of the overpopulated areas and the balanced population–grain areas are notable. The carrying capacity of land resources in the NFPE generally exhibits a positive trend with a surplus of grain; however, there are spatial variations. Areas in the south and northeast demonstrate lower change trends, while the north and southeast exhibit higher change trends. This research provides critical insights into the dynamic interplay between land, population, and grain, enabling informed decision making for sustainable development in the NFPE and offering valuable lessons for similar regions globally.