Urban soils are one of the most important components of urban ecosystem, which provides significant ecosystem services.The surface hardening resulted from rapid urbanization and industrialization changes the material and energy exchanges between the soil and the atmosphere, changes the physical and chemical properties of soils, changes the richness and diversity of species, leads to the deterioration of urban communities environment, and affect the urban environment and ecosystem services.Soil respiration intensity, as one of the most important indicators of soil fertility, soil texture and soil permeability, is one of the key factors of the carbon cycle in terrestrial ecosystems.The supply capacity of soil nutrients is not only reflected by the level of soil respiration, but also affected by the local ecosystem primary productivity.Therefore, the study of impacts of different land covers on soil respiration rate is important for carbon cycle in urban areas.In this paper, the surface hardening is divided into full and part built-up lands, and the soft-cover land with grass is chosen as the contrast.Combining on-site sampling method with field experiments, the response mechanism of ecophysiology of soil respiration in urban areas with different surface hardening is investigated.This research aims to explore the service and stress response mechanism between soil respiration and urban environment, clarify the response mechanism and its difference under different surface hardening types, and reveal the coupling relationship and effecting mechanism between soil respiration and environmental factors.This study can provide scientific experimental parameters for improvement of ecological benefits of urban plants and optimization of urban land structure for ecosystem services, which has important theoretical and practical significance to urban ecosystems.
The rapid development of urbanization makes the urban land use types changed in much degree.The original natural landscape is replaced by so many artificial buildings.Soil respiration in urban areas is one part of the terrestrial carbon flux, which is very of importance to ecosystems.Therefore, study spatial and temporal variability of soil respiration on different surface covers in urban areas and its effects on urban environment and ecosystem services is of great significance.In this article, using Licor-6400-09 soil chamber system to measure soil respiration and its main regulating factors on the three different types of urban surface covers (totally impervious cover(TIC), partially impervious cover(PIC)) and turf surface cover(TC) in Beijing, China.The results indicated that: (1) The mean annual soil respiration rate in TIC, PIC, and TC was 7.928, 5.592 and 2.625 μmol·m^-2·s^-1, respectively.The maximum of 14.785, 10.296, and 5.143 μmol·m^-2·s^-1in Summer, and the minimum of 0.490, 0.319, and 0.239 μmol·m^-2·s^-1 in Winter, respectively.(2) The mean soil respiration rate was significantly different among the three different land covers (P<0.05).The order of the mean soil respiration rate was: TC< PIC< TIC.(3) Soil respiration was significantly correlated to soil temperature on the three different types of urban surface covers, The order of Q₁₀ value was: TC< PIC< TIC.(4) Soil respiration was significantly correlated to soil moisture and soil conductivity, but it is very complicated, which needs to be further studied in the future.