Soil respiration responses to soil physiochemical properties in urban different green-lands: A case study in Hefei, China

Soil respiration (RS) is an important carbon budget in urban ecosystem. In order to better understand the limiting factors affecting urban soil respiration, we measured RS, soil temperature, soil moisture content, soil organic carbon (SOC), nitrogen (N), C/N, dissolved organic carbon (DOC), microbial biomass carbon (MBC), NO3−-N, NH4+-N, P and fine root biomass from twelve sites of four green-land types (campus green-land, park green-land, residential green-land and factory green-land) for two years in built-up areas of Hefei, China. The results showed that average annual RS was significantly lower in the residential green-land (1.35 μmol m−2 s−1) than in the campus (2.64 μmol m−2 s−1) and park (2.51 μmol m−2 s−1) green-lands. RS positively increased with soil temperature at the range of 2.01–31.26 °C, and Q10 values ranged from 1.48 to 1.65 in the four types of green-lands. Soil moisture (18–25%) showed significantly positive correlation with soil respiration (P<0.01). When precipitation occurred frequently in wet summer, soil moisture served as the dominant control on RS variations. RS was positively related with SOC, NO3−-N, P and fine root biomass (diameter <2 mm), while negatively correlated with DOC at 0–10 cm depth. Our results indicate that decreasing RS may be an optional way to increase carbon sequestration potential for urban ecosystem, and this can be achieved by regulating green-land types and applying appropriate soil nutrients maintenance practices.