Question: How much carbon can a hectoar of ground take

Asaf Shnel answered on 2 Nov 2020:

I don’t have an exact number for you, but there are a few things that will affect how much carbon a soil can hold. More important is if a soil is absorbing or releasing carbon. Here are the main factors that will affect the carbon status in a soil.

1) Soil type and more specifically the amount of clay particles in the soil will influence the amount of carbon in a soil. This very small clay particles can bind to organic matter which is very rich in carbon. By binding to the organic matter which is the remains of dead animals and plants in the soil, the clay protects it from microorganisms that feed on the organic matter and when doing so release carbon dioxide which can escape to the atmosphere. So soils with a lot of clay can protect more of the organic matter in the soil from the activities of microorganisms.

2) Climate. Again will affect the rate of activity of microorganisms. Microorganisms are usually more active in warm and humid environments, They need water but also oxygen to be most active. But very wet soils reduce the flow of oxygen in the soil. So a wetland in a mild climate like Ireland can store a lot of carbon by inhibiting the activity of microorganisms due to the lack of oxygen in the soil but still allowing enough plant growth that captures carbon from the atmosphere. the dead plant material breaks down very slowly because of the low levels of oxygen in the soil.

3) Land management. When agricultural land is ploughed the soil is aerated which will increase the activity of microorganisms, and therefore the breakdown of organic matter, releasing carbon to the atmosphere. an arable field which is ploughed every year will lose more carbon compared to a pasture which could be absorbing carbon.