The dynamic evaluation of cropland resource reserves in Mid-inner Zhejiang under urban network development

During market-oriented economic development over more than 40 years in China, construction land expansion of the Urban Cluster in Mid-inner Zhejiang has occurred primarily at the expense of cropland, forestland and water, with cropland accounting for the largest proportion. To guarantee space for grain production, the control of cropland inflow and outflow should be standardized. Based on the reserve analysis of cropland resources in Mid-inner Zhejiang, the cropland characteristics of inflow and outflow were discussed according to three types: undisturbed, reclaimed and abandoned croplands. Moreover, by elevating the analysis to the “production-living-ecological” space dimension, the greenness index (fractional vegetation cover, Fc) was adopted as a representative to evaluate spatial quality, with the aim of supporting the protective construction of cropland resources and territorial spaces in Mid-inner Zhejiang. The cropland area was maintained in the range of 3.00–3.50 × 10³ km², with a proportion of 0.200–0.350, while the decrease was 550.487 km² in the past 30 years, with a proportional decrease of 0.041. Specifically, the cropland resource reserves of the Urban Cluster in Mid-inner Zhejiang were distributed mainly in Lanxi, Longyou and Wucheng, with an area of 400.00–600.00 km². Pan'an, Wuyi and Jinyun possessed significant potential for the development of cropland resource reserves, with a growth rate of 0.15%–0.50%. While the undisturbed cropland exhibited a continuous downward trend, reclamation mainly occurred at the junction of hills and basins (Wuyi), and abandonment occurred along the development axis of the Urban Cluster in Mid-inner Zhejiang, which is centered around Dongyang-Yiwu and Wucheng-Lanxi.