Mowing changes the chemistry of urban lawns – new publication

What is the optimal mowing frequency for urban lawns? This question has long been debated by scientists, urban green space managers and city residents. Supporters of frequent mowing emphasise its aesthetic value, safety and the functionality of green areas, whereas advocates of less frequent mowing point to its positive effects on the taxonomic and structural diversity of vegetation, the amount of accumulated biomass and, consequently, on ecosystem services such as mitigating the urban heat island effect and improving air quality. Until now, however, one important aspect has largely been overlooked – the chemical composition of plant biomass. Mowing practices may alter it, thereby affecting herbivorous organisms and, ultimately, the functioning of urban food webs.

A new study published in Journal of Environmental Management provides evidence for a relationship between mowing frequency and the chemical composition of plant biomass. The research was conducted on roadside lawns in Kraków and Katowice, comparing sites mown once, three times or six times per year. The authors – a team of researchers from the W. Szafer Institute of Botany, Polish Academy of Sciences, the Jagiellonian University and the University of Silesia in Katowice, led by Dr Małgorzata Stanek (IB PAS) – demonstrated that frequent mowing significantly alters the elemental stoichiometry of aboveground plant tissues. It increases the concentrations of phosphorus, potassium, sodium, and magnesium while reducing the concentrations of several metals, including toxic lead as well as biologically important micronutrients such as iron, manganese, copper, and zinc. Importantly, some of these changes could not be explained by shifts in plant species composition and were instead a direct consequence of mowing itself.

The study does not determine whether urban lawns should be mown more or less frequently. It does, however, demonstrate that the elemental composition of plant biomass – alongside its quantity and diversity – should be considered when discussing urban green space management.

Original article:

Filipiak M., Filipiak Z.M, Kapusta P., Stefanowicz A.M., Banaś A., Biela M., Stanek M. 2026. Mowing reshapes the multielement stoichiometry of aboveground plant matter: A lesson from two cities for urban lawn management. Journal of Environmental Management 411: 130162. DOI

The research was carried out within the ToBeLawn project, "Towards better management of urban greenery – the impact of mowing on the roadside lawn ecosystem", funded by the Polish state budget under the Ministry of Education and Science programme "Science for Society" (2023–2025; project No. NdS/550099/2022/2023), led by Dr Małgorzata Stanek.

More about the study is available in an article published by Nauka w Polsce (Science in Poland) (Polish version only).