The effect of urbanization on soil properties and soil organic carbon accumulation in topsoil of Pruszkow - a medium-sized city in the Warsaw Metropolitan Area, Poland

The objective of the study was to determine properties of soils located within a city, and to assess the effect of anthro-popressure on the accumulation of carbon and nitrogen in soils of Pruszkow - a medium sized town in central Poland. Surface soil layers (0 - 20 cm) were collected at 36 sites. A total of 12 samples from lawns, 11 from allotment gardens, 9 from fields and 4 from fallow lands were subject to analysis. Lawns and allotment gardens were treated as central zone I - under strong pressure of anthropogenic factors, fields and fallow lands were treated as zone II - with potentially low level of anthropogenic influence. The statistical analysis showed significantly higher (p=0.008) amount of organic carbon (Corg) in lawns (mean 20.5 g.kg(-1)) and allotment gardens (21.7 g.kg(-1)) - zone I, than on fallow lands (10.4 g.kg(-1)) and fields (1.27 g.kg(-1)) -zone II. The surface layer of soil from allotment gardens also contained significantly higher amount of total nitrogen (mean content 1.1 g.kg(-1)) than others. The amounts of Corg not depending on the soil texture and very high C/N ratio, suggests the anthropogenic origin of the carbon. The C/N ratio was the highest in the soils of lawns (mean value 26.2) and significantly differed (p=0.04) from C/N ratios in soils of fields and allotment gardens. This suggests low intensity of humus transformation. Other chemical characteristics as hydrolytic acidity (Ha), cation exchange capacity (CEC), exchangeable base cations (EBC) and EBC share in CEC were also higher in central part of Pruszk o w town (zone I), indicating the effect of urbanization on soil properties.