关键词: 磷组分, 种植制度, 红壤, 磷有效性

Abstract: Based on the 1979, 1992, 2001 and 2006 satellite images, the spatial expansion information of Shenyang City was extracted by human-computer interactive method, and the temporal and spatial expansion characteristics of Shenyang City as well as their driving forces were analyzed from the aspects of growth intensity, center coordinates, compact index, fractal index, and elasticity coefficient, with the help of the statistic and analytic functions of GIS for the spatial data. The results showed that in 1979-2006, both the urban build-up area and its expansion rate in Shenyang were increased continuously, and reached the maximum in 2001-2006. The urban expansion showed obvious spatial heterogeneity, with the gravity shifted to the southwest. In the meantime, the compact index was decreasing while the fractal index was increasing, implying that the urban spatial configuration in Shenyang became more and more complex. Natural environmental factors, economic development, population growth, traffic infrastructure construction, and government policy and planning were the main driving forces of the urban expansion.

Key words: cropping system, red soil, phosphorus fractionation, phosphorus availability