To mow or not to mow? Effect of mowing frequency of urban lawns on soil mesofauna feeding activity

Reducing the frequency of lawn mowing can be a nature-based solution for adapting to climate change in urban areas. Reducing mowing has many ecological benefits, but it is not clear how it affects soil mesofauna, an extremely important element of terrestrial ecosystems. This study is based on a field experiment conducted on the public grounds of a university campus in Poland. In the experiment, 64 experimental plots were established and paired into 32 adjacent plots, where one plot was mowed once a year and the other plot in the pair was mowed in a different regime, including one mowing every 2 years and mowing 4, 6 and 8 times a year (n=8). The effect of mowing on the feeding activity (FA) of the soil mesofauna was assessed during the 2-year experiment using the bait lamina test. The mean FA on individual plots was 2.95% (± 1.24%) per day and was not affected by mowing frequency, soil temperature, or soil moisture. However, more frequent mowing (4, 6, and 8 times per year) resulted in a steeper decline in FA with soil depth, and the effect was most significant for mowing 8 times per year, amounting to an additional 15% decline in FA along the vertical soil gradient sampled. Therefore, in temperate climates, the recommended frequency of mowing is the same as for other groups of organisms, including plants, i.e. once or twice a year. Reduced mowing frequency allows better functioning of the anthroposols for their naturalisation by activating the deeper soil horizons.