Today I was curious to better understand the contribution of lawns to carbon sequestration. I have obsessively weeded dandelions from the yard we have. I let the grass grow pretty long and mow it every two to three weeks and leave the clippings on the grass. Now I am questioning if the dandelions are actually really healthy given the tap roots and should I just allow the lawn to go bigger with dandelions and not obsess on weeding. The green lush grass is nice to see out the window but I am not sure if that is from decades of society pushing green grass. As I am fuelling my curiosity on carbon sequestration and also related I believe absorbing more water I want to know if I should rethink my approach.
Here are the results of a bit of research I did to address my above curiosity.
- Carbon Sequestration in Lawns:
- Grass, like other plants, absorbs carbon dioxide during photosynthesis and stores it in the soil.
- The effectiveness of lawns as carbon sinks varies depending on factors such as grass species, soil type, lawn health, and maintenance practices.
- A lawn, measuring 50 x 100 feet, translates to approximately 464.52 square meters. While I need to find out the type of grass I have, based on the estimated range of carbon sequestration rates for well-maintained turfgrass, your lawn could potentially sequester between:
- 46.45 kilograms of carbon per year (using the lower estimate of 100 grams of carbon per square meter per year).
- 209.03 kilograms of carbon per year (using the higher estimate of 450 grams of carbon per square meter per year).
- Dandelions and Biodiversity:
- Contrary to being mere weeds, dandelions are beneficial for lawns and the environment. I have found that sheep like to eat the dandelion flowers as well. Some more info on dandelion here.
- Their deep taproots bring up nutrients from deeper soil layers, benefiting other plants.
- Dandelions also improve soil aeration and attract beneficial insects, thus contributing to biodiversity.
- Lawn Mowing Practices:
- Allowing grass to grow longer and reducing mowing frequency can enhance carbon sequestration.
- Longer grass enables more effective photosynthesis and develops deeper roots, thus increasing carbon storage in the soil.
- Leaving grass clippings on the lawn returns nutrients and carbon to the soil.
- Water Absorption:
- A diverse lawn, including “weeds” like dandelions, improves soil structure and health.
- This diversity enhances the lawn’s ability to absorb and retain water, reducing runoff and the need for additional watering.
- Environmental Impact of Lawn Maintenance:
- It’s important to consider the environmental impact of lawn maintenance practices.
- For instance, frequent mowing with gasoline-powered mowers emits greenhouse gases. I do have a gasoline mower so will need to think about that. I have done some research on the robot lawn rowers and I can intrigued. I do not mow very frequently.
- The use of fertilisers and pesticides also poses negative environmental impacts. I don’t using any fertiliser in the lawn.
References to carbon sequestration in turf grass. These might be the beginning of a lead into my other calculations I am looking for on carbon sequestration.
- “Carbon Sequestration in Turfgrass-Soil Systems”
- Authors: Ruying Wang, Clint M Mattox, Claire L Phillips, Alec R Kowalewski
- Published in: PubMed
- Abstract: This study reviews recent carbon sequestration research in turfgrass and compares turfgrass systems to other plant systems. It highlights that turfgrass systems can be carbon-neutral or carbon sinks, with the effectiveness depending on management practices and turfgrass species. The study emphasizes the importance of choosing appropriate turfgrass species and management practices to enhance carbon sequestration.
- “High soil carbon sequestration rates persist several decades in turfgrass systems: A meta-analysis”
- Authors: Claire L Phillips, Ruying Wang, Clint Mattox, Tara L E Trammell, Joseph Young, Alec Kowalewski
- Published in: PubMed
- Abstract: This meta-analysis of 63 studies, primarily in the U.S., evaluated soil carbon sequestration rates in turfgrass over time. It found that newly established turfgrass had high carbon sequestration rates, with an average soil carbon sequestration rate of 5.3 Mg CO2 ha^-1 yr^-1. However, the study observed that these rates decline over time, reaching a mean rate not significantly different from zero at 50 years. The study also discusses the impact of management practices, including mowing and fertilizer use, on carbon sequestration.