Logical correlation, realistic contradictions and path optimization for promoting grain production through cultivated land utilization under carbon emission constraints

Cultivated land is the most important carrier of grain production. Quantity, quality, and utilization rate can also determine the production capacity of grain for national grain security. Among them, agricultural carbon emission has been one of the important sources of greenhouse gases. There is a complex logical relationship among land use, land use carbon reduction, and grain production under the strategic context of climate change response to the overall layout of ecological civilization. In response to the growing demand for grain, agricultural production factors in the short term have caused ecological pollution and carbon emissions in cultivated land. The demand for diversified agricultural products has also intensified the excessive investment of production resources, further deteriorating the ecological environment of cultivated land and carbon emissions. Therefore, this study aims to explore the relationship between cultivated land utilization and grain production in the context of carbon emission constraints, in order to reveal the complex logical relationship among the three elements of "soil-carbon-grain". The challenges were also proposed to sustainably utilize the cultivated land under the goals of grain security and carbon emission reduction. Furthermore, the optimal paths were constructed to promote the green transformation and upgrading of cultivated land use for better grain production. The results showed that: (1) A complex "soil-carbon-grain" factor system was obtained to form the logical connection between cultivated land utilization and grain production under carbon emission constraints. (2) The carbon reduction was implemented to utilize the cultivated land under current agricultural production. There were uncertain impacts on national grain security. But the ever-increasing grain production still resulted in a large amount of carbon emissions. (3) There was a better balance between cultivated land utilization and grain production under carbon emission constraints. A coordinated optimal path was established for the "soil-carbon-grain" elements from three aspects: cultivated land protection, carbon reduction, and grain production. The cultivated land resources were allocated to construct a carbon trading market for the structure of grain production. According to the current agricultural production, it was still feasible to coordinate the "Carbon Peaking and Carbon Neutrality" goals with grain security goals, although there was a high degree of uncertainty on carbon emissions that were reduced from cultivated land utilization. The proportion and quantity of input were optimized from the factors of grain production, in order to implement the "Trinity" protection system for the cultivated land, differentiated carbon reduction for cultivated land use, and stable support of agricultural funding. A mature trading market of agricultural carbon was established to innovate the green technologies of agricultural production. The carbon emissions were reduced from the cultivated land use for the national grain security, the carbon sequestration emission reduction potential of cultivated land, and grain production. It is very necessary to plan the spatial patterns of cultivated land using various policy tools, in order to promote the sustainable and synergistic development of low-carbon and green utilization of cultivated land and national food security.