关键词: 植茶年限, 土壤团聚体, 碳、氮、磷, 生态化学计量学

Abstract: Based on the Landsat TM/OLI remote sensing images and social statistical data of Xi’an in 1984, 1996, 2006 and 2016, the construction land information in the main urban area of Xi’an City was extracted through the ArcGIS 10.5. The spatiotemporal expansion characteristics of Xi’an City were analyzed using expansion intensity, fractal dimension, and elasticity coefficient. The driving forces and the urban sprawl trend of Xi’an were also studied. The results showed that the construction land increased by 478.62 km² from 1984 to 2016, being 3.27 times larger than that in 1984. The average annual expansion intensity was 6.88% with a growth rate of 14.50 km²·a^-1. The Barycenter of Xi’an City moved toward the northwest by 1.53 km. There were two types of urban expansion pattern including filling and expansion. The urban spatial expansion was unbalance. The city was expanded from center areas (Lianhu district, Xincheng district, Beilin district) to periphery suburb (Baqiao district, Yanta district, Weiyang district and Chang’an district). In general, the coordination relationship between the urban expansion and population growth was weak, with faster urban expansion than the population growth. Under the scenarios of the restriction of land space planning and the delimitation of urban boundary line, the core construction of Xi’an City should focus on protecting the historical culture. The development of population, environment, and economy should be coordinated and population distribution should be rationally planned, with the aim to build a unique national modern central city.

Key words: tea plantation age, soil aggregate, carbon, nitrogen, phosphorus, ecological stoichiometry.