Effects of organic ground covers on soil moisture content of urban green spaces in semi-humid areas of China

In urban green spaces, it is important to maintain a suitable soil moisture content, an important indicator of plant growth. The management of urban green spaces faces great challenges in semi-humid areas of China, which are featured by interannual changes in rainfall and the alternation between droughts and floods. This paper aims to select suitable Organic Ground Cover (OGC) materials for urban green spaces in such areas, as the OGC can effectively absorb water and suppress the evaporation of soil moisture. For this purpose, 16 OGC materials were selected for our experiments, and 33 identical holes were dug on a field of silty loam. Next, 16 holes were separately covered by a 5 cm-thick layer of the 16 materials, 16 holes were separately covered by a 10 cm-thick layer of the 16 materials, and 1 hole was taken as the control sample (CK). On this basis, the authors explored how the 16 materials in two different thicknesses affect the soil moisture contents in four different soil depths. The results show that: When the OGC layer was 5 cm thick and 10 cm thick, CK had the lowest soil moisture content at any soil depth. In most cases, the soil moisture content under the same OGC material changed insignificantly with the material thicknesses, except FPB2 and CP. The layer of OGC materials should be 5 cm, if the only purpose is to increase the soil moisture content and enhance the landscape effect, and 10 cm if rainwater absorption is also taken into account. The above results provide a reference for selecting the OGC materials suitable for urban greening.