Impact of urban soil surface treatments on soil water and thermal regimes in Haplic Chernozem

Although it is known that land cover affects soil water and thermal regimes, the influence of different land covers on soil water content and temperature in urban areas is rarely explored. Five soil surface treatments were selected in this study: bare soil, concrete paving, bark mulch, mown grass, and unmown grass. Soil water contents and temperatures were measured at five depths (5, 10, 25, 50, and 80 cm) over one year. The highest water contents were recorded under mulching. Under grass, water contents were lower and showed greater oscillations due to precipitation and evapotranspiration, while under mown grass, values were higher than under unmown grass. Similarly, near-surface bare soil water contents also fluctuated. The water content under the concrete remained almost constant. While the soil under concrete paving, bare surfaces and even mown grass warmed up considerably during the day because of the absorption of solar radiation and cooled down at night due to the emission of stored heat, the soil under bark mulch and unmown grass cover showed smaller temperature fluctuations, mainly due to the low thermal conductivity of the surface layer and surface shading. The effects revealed throughout the entire soil profiles decreased with depth.