|"Green" Space? Hard-packed soil, scant cover of grass..|
Why a bug? Because it doesn’t really care about the politics and lobbying of man-made creations such as lawn-mowers or golf courses, both of whom have had a hand in the studies on the net carbon impact of turf. Some studies (Sahu 2008) show that lawns capture more CO2 than they produce, with the footnote that this doesn’t account for the fertilizer and water. It is worth noting that this study was funded by the Outdoor Power Equipment Institute. (hmm). Not surprising, other reviews take this to task and show a potential for a net increase in carbon. Without getting into the kerfuffle, the lessons learned are pretty straightforward. The biggest reduction can be achieved by eliminating the carbon footprint of fertilizers and lawn mowers. How?
The bug will tell you to take a closer look at the condition of the soil. Improving the soil organic
matter improves nearly all soil properties (e.g. moisture retention, soil
structure, drainage, nutrient storage) and provides all the necessary support
for the grasses. And soil organic matter is approximately 50
percent carbon. So as we build soil organic matter, we increase the ability of
the soil to act as a sink for carbon. Over the past 150 years, more than a third of
the CO2 we have added to the atmosphere has come from changes in land use and
poor land management, not from burning fossil fuels. It is estimated that we have lost 50-80
percent of our topsoil worldwide. To
look at it from the turfwar perspective, soils (normalized global scale) contain about three
times carbon as much as vegetation. So it makes sense both from the perspective of
carbon and from turf management to improve the soil.
|Compacted soil under a turflawn|
Improving soil organic matter is best achieved with organic materials! (Imagine that). For example, using mulching lawnmowers to add grass clippings, or spreading a layer of compost on the lawn just as they go dormant, prior to the snowfall. Compost can be sourced from municipal landfills, from compost bins, or even by inserting a handful of worm into the middle of leaf bags. It need not be expensive. And even though we have an obsession with monoculture grass in our lawns, it is much healthier and sustainable to have a meadow-type lawn, with a mix of grasses and small flowers. Even park spaces meant for regular use can benefit from a mix of grass varieties.
There is just as much debate at the feasibility and scientific basis for reducing carbon through soil improvement, as there is over the carbon sink potential of turf. But there is never any real doubt about the benefit of improving the soil, and the synergy of improving the biodiversity of both plant life and bug life. It is all part of an interwoven eco-system.
So take the time today to lay down on the lawn. Do you see lots of insects moving about? Can you poke a stick easily into the soil? How many species can you count? This is the perspective of a bug on our eco-system, the same one that supports our own human species.