关键词: 杨树-苋菜间作系统, 地表径流量, 淋溶损失量, 氮素流失

Abstract: Taking the urban central area of Shunde District, Foshan City in Guangdong Province of South China as a case, and based on landscape accessibility analysis, the ecological service function grading ranges of urban green space system was estimated, and, in considering of block population density, the current service population and carrying capacity of urban green space system were also calculated. In the study area, the urban green space types and patch distribution were not homogeneous. Green space was mainly distributed in the middle and west, but less in the densely populated area of east and north. According to the differences in the ecological service function of different green space types, and by using cost weighted distance method, the green space service zone was divided into five grades, which comprehensively reflected the differences in spatial accessibility and the ecological service function of green space system.A majority of the current service population of urban green space system was mainly distributed in the areas of grades Ⅰto Ⅲ. The calculation of the appropriate population density of the study area based on the per capita green area standard showed that, compared with the service population of urban green space system, the current service population density of the urban green space system in the study area already exceeded the carrying capacity of the green space system.

Key words: poplar-amaranth intercropping system, soil surface runoff, leaching loss, nitrogen loss.