How do tillage practices influence soil's carbon sequestration?

Tillage practices influence soil's carbon sequestration by affecting the amount of organic matter in the soil.

Tillage is the agricultural practice of preparing the soil for planting by mechanical agitation, such as digging, stirring, and overturning. This practice can have a significant impact on the soil's ability to sequester, or store, carbon. The process of carbon sequestration involves the capture and long-term storage of atmospheric carbon dioxide, a key greenhouse gas. Soils, particularly those rich in organic matter, play a crucial role in this process.

When tillage is carried out, it often leads to the breakdown of soil aggregates, exposing the organic matter within them to decomposition by soil microbes. This can result in the release of stored carbon back into the atmosphere as carbon dioxide. Therefore, conventional tillage practices can lead to a decrease in soil carbon sequestration.

On the other hand, conservation tillage practices, such as no-till or reduced-till farming, can enhance soil carbon sequestration. These practices minimise soil disturbance and maintain a protective cover of crop residues on the soil surface. This not only reduces the exposure of organic matter to decomposition but also promotes the incorporation of organic residues into the soil, thereby increasing its carbon content.

Furthermore, tillage practices can also influence the physical properties of the soil, such as its structure and porosity, which in turn affect its capacity to sequester carbon. For instance, well-structured soils with good porosity facilitate the movement of carbon dioxide out of the soil and the diffusion of oxygen into it, thereby promoting the biological processes that lead to carbon sequestration.

In conclusion, tillage practices play a significant role in determining the soil's ability to sequester carbon. By choosing appropriate tillage methods, farmers can contribute to the mitigation of climate change by enhancing the soil's capacity to store carbon.