Artificial coverage of natural soil surface by constructed material usually affects soil-atmospheric ecological processes. The exchanges of energy, water and other masses between atmosphere and soil are often restricted or hampered, and increasing ecological influences are exerted on adjacent, non-covered natural areas. At present, monitoring of urban ecological effects such as heat island, grey haze caused by urban infrastructure constructions and urban citizens' consumption have been performed with effective ecosystem observation networks, but little specific research attentions are paid to ecological effects of urban constructed surfaces or bodies on urban green space, soil and atmosphere, which play crucial roles in offering urban ecosystem services.
In this study, two types of urban typical constructed bodies or patches (asphalt and concrete), most widely appeared in urban areas, are taken to investigate changes in temperature and moisture (VWC) in the soil of green space that is next to these two-types of urban structures. We introduce an ecological observational technique of the Human-Environmental Ecotonal Gradient Transect (HEEGT), that is, the boundary between urban structures and green space or exposed covers of soil or rocks is taken as an observational gradient transect, and observational points are arranged along with the Urban Structures-Green space (or exposed Soil) Ecotonal Gradient Transect as a category of HEEGTs on a straight line or a multi-zigzag course from the edge points of artificial structures to the central areas of green space or exposed soil. The research on horizontal effects of urban structures on the soil of adjacent green space were conducted, and the magnitudes and scopes of horizontal ecological impacts of different urban constructed bodies or patches on the temperature and moisture (VWC) in the soil of adjacent green space were further analyzed, considering their structural components, size, shape and other construction characteristics. Our study results have shown that: 1) in Summer and Autumn, in the HEEGT belt of the two types of observational sites (asphalt and concrete), there is always the highest temperature of soil in the point that is just next to the constructed patches (Point a), and the farther from the point a, the lower the soil temperature. On the contrary, Point a always has the lowest value of soil volumetric water content (VWC), and the farther from the point a, the higher the soil VWC. 2) Regarding diurnal variations of soil temperatures and VWC, the increases of soil temperature and VWC are statistically more significant at noon and night than that in the early morning in the HEEGT belts for the two types of observational sites. For seasonal variations from summer to winter, the soil temperature and VWC are statistically more significant at summer and autumn than that in the winter in the HEEGT belts. When atmospheric temperature is lower than a certain value (15℃ in Beijing city), the soil temperature variation in HEEGT belts statistically tends to be unchangeable. 3) In the HEEGT belts, there exist quantitative relationships of power function between the soil temperature or soil volumetric water content with the distance away from point a, that is, T = 0.7708(579.4957-0.9984D)^0.5843 for asphalt,W= 0.1970(0.0505+0.1347D)^0.2262 for asphalt; T = 0.7615(583.7027-1.0986D)^0.5746 for concrete, W= 0.2224(-0.6019+0.3473D)^0.0595 for concrete. 4) In the HEEGT belts for the two types of observational sites, the scopes of impacts for two types of urban constructed bodies on the temperature of soils of adjacent green space vary approximately within the numerical range of 0-100 cm, often altered by the components, texture, size, and patch distributional pattern of urban structures, and urban meteorological factors, artificial management as well as the compositions and structure of adjacent green space.