东北典型黑土区耕地轮作休耕的空间重构

轮作休耕是保障黑土区耕地资源可持续利用的重要手段。科学合理确定粮食作物轮作休耕的耕地利用规模及空间分布,对实现黑土区耕地修养生息、提升地力和平衡粮食供求结构具有重要意义。以东北典型黑土区——克山县、拜泉县和依安县为研究区,运用作物种植空间适宜性评价模型、多目标优化（MOP）模型和智能体土地布局优化配置（AgentLA）模型,基于地块尺度构建耕地轮作和休耕布局,适度调整轮作休耕规模及分布。结果发现：（1）研究区主要作物种植适宜性高值和低值区存在明显空间差异。玉米和大豆种植适宜性高值区交汇于依安县北部和克山县西部,是玉米—大豆轮作优势区域。主要作物种植适宜性低值区交汇于依安县南部和拜泉县西南部,是休耕的重点区域。（2）基于种植结构优化的轮作规模实现了大豆种植比例增加和玉米种植比例减少,缓解了目前玉米阶段性供大于求、大豆供给不足的现实矛盾。通过设定多种粮食供求情景确定休耕规模有利于灵活应对粮食市场变动。（3）兼顾耕地空间适宜性和集聚性的轮作休耕布局有利于充分利用耕地资源禀赋比较优势、发展规模化经营,对提高耕地利用效率具有重要作用。研究通过科学重构黑土区耕地轮作和休耕空间布局,实现了耕地空间适宜性、空间集聚性、种植结构合理性和粮食供求稳定性的同步提升,为实现黑土区耕地资源合理可持续利用和粮食安全提供政策参考。

Spatial reconstruction of farmland rotation and fallow in the typical black soil region of Northeast China

Rotation and fallow are important means to ensure the sustainable utilization of cultivated land resources in black soil regions. Determining the scale and spatial distribution of cultivated land for crop rotation and fallow scientifically is of great significance for undertaking land reclamation, improving soil fertility, and balancing the structure of food supply and demand in the black soil regions. Taking the typical black soil regions in Northeast China: Keshan county, Baiquan county, and Yi'an county as the research area, this paper reconstructs the farmland rotation and fallow layout at the plot scale by using the crop planting suitability evaluation model, multi-objective optimization (MOP) model, and agent-based land layout optimization allocation (AgentLA) model. Findings show that: (1) There are obvious spatial differences between high-value and low-value areas of the planting suitability of main crops. The high-value areas of corn and soybean planting suitability intersect in the north of Yi'an and the west of Keshan, which are the dominant areas of corn-soybean rotation. And the low-value areas converge in the south of Yi'an and the southwest of Baiquan, which are the key areas for fallow farming. (2) The crop rotation scale based on the optimization of the planting structure has achieved an increase in the proportion of soybean planting and a decrease in corn planting, alleviating the contradiction between the current phased oversupply of corn and insufficient supply of soybeans. Determining the scale of fallow by setting a variety of food supply and demand scenarios is conducive to flexibly responding to changes in the food market. (3) A rotation and fallow layout that takes into account the planting suitability and agglomeration of cultivated land is conducive to making full use of the comparative advantages of cultivated land resource endowments, developing large-scale operations, and playing an important role in improving the efficiency of cultivated land use. This research has helped to realize the simultaneous improvement of the spatial suitability, spatial agglomeration, rationality of planting structure, and the stability of food supply and demand of cultivated land, by rationally reconstructing the farmland rotation and fallow space in the black soil region, which provides policy reference for realizing sustainable utilization of cultivated land resources and food security in black soil regions.