Carbon sequestration – The Green Tau

Counting on … day 75

27th March 2024

Agroforestry offers another approach to farming that enables the long term increased sequestration of carbon dioxide. Agroforestry has two main forms:

“Silvo-pastoral agroforestry: which means the grazing of animals under trees. The animals enrich the soil while the trees provide shelter and fodder for the animals.

Silvo-arable agroforestry: where crops are grown beneath trees, often in rows which are large enough for a tractor to tend to the crops without damaging the trees. This is farming in 3D, the trees and the crops occupy different levels above ground, and also below ground where the tree roots will reach down deeper than the crops.”(1)

The additions of trees in the farm enhances the amount of carbon dioxide that is being . At the same time the practice also benefits the condition of the soil. “Tree roots reach deep into the ground, releasing much-needed carbon into the soil. They cycle nutrients and bind the soil together, preventing it from being eroded by the wind or the rain.”(1)

(1) https://www.soilassociation.org/causes-campaigns/agroforestry/what-is-agroforestry/

Counting on … day 74

26th March 2024

Regenerative farming is one way in which carbon dioxide levels can be reduced. Regenerative farming aims both to increase the amount of carbon stored in the soil and the plants it sustains, and by lowering livestock numbers, reducing emissions. Livestock account for about 14% of greenhouse gas emissions.

For further reading – https://greentau.org/2023/12/15/windows-of-opportunity-16/

Counting on … day 72

22nd March 2024

Carbon sequestration is a formal name given to the processes by which carbon is captured from the atmosphere and stored on a long-term basis. Such long-term storage might include peat bogs, forests, kelp beds etc and may be referred to as ‘carbon sinks’.

Carbon sequestration can be used as a means of mitigating the effects of climate change. This can be biologically by, for example, planting more forests, restoring peat bogs and wetlands, and re-establishing kelp meadows. This natural sequestration can be enhanced, in the case of forests, by using felled timber to make items such as buildings, furniture etc and keeping those items for hundreds of years. However growing trees for timber needs to be carefully managed to a) maximise the carbon captured by the growing tree, and b) to maximise the flourishing of biodiversity.

Carbon can also be sequestered geologically if the CO2 can be captured eg from a cement factory. Then the CO2 “can be compressed to ≈100 bar into a supercritical fluid. In this form, the CO2 could be transported via pipeline … and injected deep underground, typically around 1 km, where it would be stable for hundreds to millions of years.” (https://en.wikipedia.org/wiki/Carbon_sequestration)

Turning your garden into a carbon sink

As well as minimising the amount of carbon we emit/ consume/ use we need also to do all we can to keep as much carbon locked away undisturbed in the ground. Our gardens can be made into carbon sinks ie net absorbers of carbon.

Don’t buy or use peat. The UK’s peatlands are an important carbon sink (1 hectare of peatland can absorb up to 2000 tonnes of CO2 per year). Digging up and removing the peat seriously damages these fragile habitats.
Don’t buy plastic plant pots whether with or without plants (plastic is made from oil). Instead use pots made from plant fibres, paper or clay. The Hairy Plant Pot Company grows plants for sale in coir pots. The whole pot with plant goes straight into the solid where the coir will decompose over time.
Don’t use artificial fertilisers, pesticides or herbicides. These have a high carbon footprint and are damaging to natural ecosystem.
Make a compost bin and fill it with garden waste and plant based kitchen waste. Once well rotted, the bin’s contents will provide soil enriching natural compost that locks the carbon into the soil. Compost bins can be made from wood (eg recycled pallets), wire mesh or you could buy a plastic bin made from recycled plastic.
Plant trees and shrubs as these will, by their size, be able to absorb more carbon as they grew.
Opt for perennial plants over annuals. The perennial plant both develops a larger root mass and has a longer growing season enabling it to absorb more carbon. Interestingly you can opt for perennial varieties of vegetables rather than growing them each year from seed: spinach, watercress, kale, perennial leeks and onions, cabbage etc.
Choose plants that will be happy in the micro environment that your garden offers. You can waste time, energy and carbon, trying to make plants grow where the conditions are unsuitable. Grow together plants that form a natural ecosystem so that they help each other.
Avoid over digging the soil as this can release carbon locked into the soil.
Avoid leaving the earth bare as carbon from the soil can easily be lost into,the atmosphere. Instead cover the earth with a mulch or with a cover crop.
Let your lawn grow. Frequent cutting of the grass requires the input of water and fertilisers to keep it green and the lack of depth of cover makes it susceptible to drying out during periods of drought. Instead let the grass grow longer – you can still run over it, sit on it and play on it.
Transform your lawn into a meadow by introducing a greater variety of plants, especially flowering ones. These extra plants will tend to have longer root systems enabling more carbon to be absorbed by the soil.
Avoid or replace hard surfaces, especially concrete ones. (Concrete has a particularly high carbon footprint). Hard surfaces leave the soils underneath compacted and bereft of mini beasts and micro organisms that absorb carbon. Use gravel and bark in preference to paving stones, or even bricks set in sand.
Build a pergola so that you can grow climbing plants to provide shade in the summer. Consider adapting any garden sheds so that you can plant them with a green roof. The more we plant, the more carbon our garden can absorb.