摘要：An assessment of C and N balance in urban soil compared to
the natural environment was carried out to evaluate the influence of
biological processes along with human-induced forcing. Soil C and N
stocks were quantified on the samples (n=18) collected at 5 - 10 cm depth
from dominated green areas and arable lands in the city of Wroclaw
(Poland) and the relatively natural grassland located ca. 36 km south-west.
Higher soil carbon and nitrogen levels (C/N ratio = 11.8) and greater
microbial biomass C and N values (MBC = 95.3, MBN = 14.4 mg N kg-1)
were measured in natural grassland compared with the citywide lawn sites
(C/N ratio = 15.17, MBC = 84.3 mg C kg-1, MBN = 11.9 mg N kg-1),
respectively. In contrast to the natural areas, the higher C and N
concentration was measured in urban grass dominated soils (C = 2.7 % and
N = 0.18 % of dry mass), which can be explained mainly due to the high
soil bulk density and water holding capacity (13.8 % clay content). The
limited availability of soil C and N content was seen under the arable soil
(C = 1.23 %, N = 0.13 %) than in the studied grasslands. In fact, the
significantly increased C/N ratios in urban grasslands are largely
associated with land conversion and demonstrate that urban soils have the
potential to be an important reservoir of C.
其他摘要：An assessment of C and N balance in urban soil compared to the natural environment was carried out to evaluate the influence of biological processes along with human-induced forcing. Soil C and N stocks were quantified on the samples (n=18) collected at 5 - 10 cm depth from dominated green areas and arable lands in the city of Wroclaw (Poland) and the relatively natural grassland located ca. 36 km south-west. Higher soil carbon and nitrogen levels (C/N ratio = 11.8) and greater microbial biomass C and N values (MBC = 95.3, MBN = 14.4 mg N kg-1) were measured in natural grassland compared with the citywide lawn sites (C/N ratio = 15.17, MBC = 84.3 mg C kg-1, MBN = 11.9 mg N kg-1), respectively. In contrast to the natural areas, the higher C and N concentration was measured in urban grass dominated soils (C = 2.7 % and N = 0.18 % of dry mass), which can be explained mainly due to the high soil bulk density and water holding capacity (13.8 % clay content). The limited availability of soil C and N content was seen under the arable soil (C = 1.23 %, N = 0.13 %) than in the studied grasslands. In fact, the significantly increased C/N ratios in urban grasslands are largely associated with land conversion and demonstrate that urban soils have the potential to be an important reservoir of C.
