An in-depth exploration of the dynamics and existing problems in farmland morphology is crucial to formulate targeted protection policies. In this study, we constructed a morphological evaluation index system to identify the characteristics of farmland use transition in Sihong County of the Huang-Huai-Hai Plain, China. The dominant morphology in terms of area and landscape pattern and the recessive morphology focusing on function were considered in this work. Based on this information, the driving factors of farmland use transition were quantitatively analyzed via the mixed regression model. The following major findings were determined: (1) The area showed a U-shaped change trend during 2009–2018. The patch density (PD) showed an upward trend, and the mean patch size (MPS) showed a downward trend, indicating that the degree of farmland fragmentation increased. The implementation of land consolidation projects increased the area and aggregation of farmland, while urbanization and road construction occupied and divided the farmland, leading to a reduction in area and increase in the degree of fragmentation. (2) The crop production, living security, and eco-environmental function of farmland showed a trend of first decreasing and then increasing. Urbanization increased the demand for agricultural products and the degree of large-scale agricultural production and had a positive impact on the crop production and eco-environmental function of farmland. Our research highlights that increasing farmland fragmentation should be addressed in the farming area. Therefore, the government should formulate efficient policies to curb farmland occupation for urban and traffic utilization.

The sustainable utilization of regional cultivated land systems in the Yangtze River Delta (YRD) region over the past 40 years has been severely impacted by rapid urbanization processes. Improving the eco-efficiency of cultivated land use (ECLU) plays a significant role in achieving the sustainable utilization of farmland and high-quality development of agriculture and rural areas. In this study, the spatial–temporal features and influencing factors of the ECLU in the YRD are investigated by various methods, such as a super-efficient SBM model, hot spot analysis, Dagum Gini coefficient, and panel tobit model. The findings indicate the following: the ECLU showed an overall high level from 2000 to 2020; the ECLU varied significantly over time and space in the YRD. The ECLU presented obvious spatial agglomeration in the YRD: southern regions exhibited a concentration of cold spots, while hot spots were primarily found in the east and north of the YRD. The trend of regional differences in ECLU during the research period fluctuated upwards in the YRD, and the density difference super-variable was the main source of regional differences. Increases in urbanization level and GDP per capita contributed to ECLU enhancement in the YRD, and agricultural intensity levels and agricultural industrial structures played a negative role in ECLU improvement. Finally, we suggest that different regions should adapt to local conditions, scientifically and reasonably allocate cultivated land production resources, and promote the coordinated improvement of ECLU. This study could provide a reference for policymakers to formulate better decisions on cultivated land utilization and management.

Understanding the land use/cover changes associated with agricultural production is essential for food security in increasingly urbanizing areas. Such studies have been widely conducted in different regions of China; yet, its major grain-producing regions (MGPRs) remain less studied. To address this knowledge gap, we conducted analyses of the land use conversion matrix, spatial hot spots, decoupling, and index evaluation from a spatiotemporal perspective, to quantify the MGPRs’ farmland changes and its grain production efficiency and ecological security during 2000–2020. The results showed the following: (1) Farmland in the MGPRs experienced a net decline of 2.54 × 10⁴ km², with significant spatial heterogeneity in the area, extent, and speed of loss/gain. (2) Farmland gain came from mostly forest, grassland, and unused land, with hotspots in northeastern China, while farmland loss increasingly changed to construction lands, with hotspots covering east-central China and in the suburbs surrounding capital cities. (3) Grain production in the MGPRs increased by 1.6 times in the past 20 years, via its strong decoupling from farmland quantity in especially central-eastern China. (4) Land ecological security in the MGPRs was less secure but has been improving with non-homogeneous regional differences, while it demonstrated a spatial pattern of “higher security in the north–south and lower in the middle”. Our findings suggested that China’s MGPRs would continue to lose farmland and China’s food security should require a sustainable decoupling of grain production and farmland quantity while maintaining ecological security. This study has significant policy implications for farmland conservation in China’s MGPRs, as well as highlighting the landscape sustainability opportunities of urbanization-associated farmland loss in densely populated human–environment systems in general.