Study on the spatial structure of cultivated land in Beijing based on the spectrum and fractal characteristics

The spatial structures of five types of cultivated land with various economic attributes in Beijing are analyzed in this paper based on natural attributes in the context of harmonious development of urban and rural functions.The spectrum analysis shows that the layout of different types cultivated land has different periodicity,and that they together form the spatial structure of macroscopic suburban agriculture,about 23-44 km(suburban plain),44-66 km(exurb plain),66-126 km(mountain) from Tian'anmen.Based on this analysis,the paper calculates the spatial dimension and Hurst index of four cultivated land types,and argues that the cultivated lands of landscape greening area,beautified farmland area and the 22-47 km circle of suburban mountainous areas do not have fractal characteristics.The development of scale farmland area is affected by distance,and landscape corridor belt is impacted by urban development,and the 48-126 km circle of central suburbs and mountainous areas is affected by natural conditions.The fractal characteristics of the cultivated lands of the three are obvious.On the whole,cultivated land in Beijing is in a discrete-continuous and commensurability-incommensurability integration status.