Evolution of agricultural planting structure in the Northern Hebei Plateau

The Northern Hebei Plateau, a pivotal agricultural region in Hebei Province, serves as a crucial ecological buffer for the Beijing-Tianjin-Hebei Region. Analyzing the spatiotemporal patterns of crop planting structures in this area and elucidating the evolution of crop planting structures across the Beijing-Tianjin-Hebei are essential for addressing regional water scarcity, sustaining agricultural development, and preserving ecological equilibrium. Previous studies on the crop planting structure of the Northern Hebei Plateau have primarily relied on statistical findings, lacking comprehensive exploration of spatial distribution changes influenced by policy and economic factors, facilitated by remote sensing technology. Leveraging MODIS NDVI remote sensing image data, a 30 m land use dataset, and statistical yearbooks, this study classified and delineated the cultivation areas of major crops such as spring wheat, naked oats, flax, vegetables, and potatoes in 2000, 2010, and 2020. The analysis focused on understanding the spatiotemporal dynamics of crop cultivation patterns in the region. The findings revealed several key insights: 1) Remote sensing monitoring results demonstrated strong correlation with agricultural statistics, R² is 0.61 and consistency index is 0.96. The validation using the Kappa coefficient yielded 0.84, with an overall classification accuracy of 87.65%. 2) Between 2000 and 2020, influenced by economic and policy factors, the total arable land area in the Northern Hebei Plateau exhibited a declining trend. While spring wheat and naked oats continued to dominate, traditional crops (spring wheat, naked oats, and flax) areas decreased by 50.7%, whereas economic crops (potatoes and vegetables) area increased by 211.4%. 3) In 2020, nearly 51% of the planting area of spring wheat and naked oats concentrated in the northern part of Kangbao County. The area devoted to flax declined by 57.0%, shifting towards the northern part of Shangyi County, while vegetable cultivation expanded by 19 877 hm², indicating a trend towards decentralization. The potato cultivation area also expanded, particularly in the northern part of Shangyi County, northern part of Guyuan County and northwest Zhangbei County. 4) There were notable differences in agricultural land changes among the four counties. Kangbao County experienced the smallest decrease in spring wheat and naked oats planting area, whereas Shangyi County witnessed a 129.2% increase in flax planting and a sixteen-fold increase in potato cultivation area. Changes in vegetable planting area were relatively minor across the counties. 5) The “Two Zones” of the capital city construction policy, market orientation, and economic incentives for crops emerged as critical factors shaping the agricultural planting structure of the Northern Hebei Plateau. This study provides empirical data supporting adjustments in planting structure and rational allocation of water resources in the region.