Less intensive management of lawns promotes soil biodiversity

A study shows how less intensive management of lawns, especially of those surrounding homes, allows to support many below-ground species that contribute to the balance of the ecosystem

by Matteo Cavallito

Managed lawns, such as those in private gardens, public parks or sports fields, are known to be often under intensive care. These operations allow them to maximize their aesthetic impact. But at the same time, they risk damaging their underground biodiversity. This is claimed by a study from Cornell University, published in the journal Urban Forestry & Urban Greening. In contrast, the research explains, less intensive grassland management can increase the richness and diversity of soil organisms.

Over 160,000 km2 of turfgrass in the U.S.

“Turfgrass, an integral part of the built environment, covers a land area greater than 163,000 km2 in the United States,” the study explains. “Particularly prominent are lawns, which we define as turfgrasses which surround human habitations like homes, public parks, and businesses, which are regularly managed to simultaneously maximize recreational, cultural, and aesthetic goals.”

The authors, in particular, noted how less intensive management of lawns characterized, for example, by reduced pesticide use benefits certain organisms such as mesostigma mites. Which, says a Cornell statement, are among the major natural predators of agricultural pests such as nematodes. The mites, the researchers explain, play a controlling role in underground food webs. And thus contribute to soil ecosystem health.

The experiment

Conducted at Cornell AgriTech, an experimental center located in Geneva, New York State, the study looked at three different lawn management strategies: high intensity (with regular use of pesticides, fertilizer and herbicides), medium intensity (with two fertilizer applications and limited pesticide use) and low intensity (with only weekly mowing). The researchers took soil samples from each area over a two-year period.

This enabled them to assess the biodiversity of subterranean organisms, soil chemical and physical properties, microbial biomass and soil water content.

“Our results show that decreasing management intensity leads to increases in the abundance, richness, and diversity of soil fauna communities, with these changes being most apparent in certain taxa like predatory mites (e.g. Mesostigmata),” the study explains. In summary, low-intensity management was associated with the presence of as many as 87 different species of subterranean organisms. In contrast, high-intensity management had a negative impact on the diversity of them.

A balance between aesthetics and biodiversity of lawns

If managed properly, in short, lawns not only contribute to environmental health but can also support a wide range of understory species which play a crucial role in preserving the balance of the ecosystem. A reduction in pesticide and fertilizer use, the research notes, can improve soil health and biodiversity without unduly limiting the functionality and aesthetics of the landscape.

“Our study contributes to the growing body of literature advocating for ecologically minded turfgrass management,” the authors explain. “While the challenges of balancing aesthetic and ecological objectives in turfgrass lawns remain, our findings suggest that strategic implementation of low-input practices can mitigate some negative impacts of lawn management on belowground communities and processes.”