Opinion | Capturing carbon in soil
Covid-19 has been terrible to this world. But there is something worse we could face: a full-blown climate crisis. If you want to understand the kind of damages that climate change will impose, as Bill Gates puts it, look at Covid-19 and spread the pain out over a much longer period of time. The loss of life and economic misery caused by this pandemic would be much less compared to the damages wrought by carbon emissions.
The world did not do enough to prepare for the pandemic. We can avoid making the same mistake with climate change. There is no single silver bullet to stop climate change but increased soil organic carbon (SOC) has been recognized as one of the best, most cost-effective, and environment-friendly options for climate change adaptation and mitigation, as well as for combating food insecurity, desertification, and land degradation.
SOC is a complex mixture of carbon compounds, consisting of decomposing plant and animal tissue, microbes (protozoa, nematodes, fungi, and bacteria), and carbon associated with soil minerals. Carbon can remain stored in soils for millennia, or be quickly released back into the atmosphere. Climatic conditions, natural vegetation, soil texture, and drainage all affect the amount and length of time carbon gets stored.
Through the process of photosynthesis, plants assimilate carbon and return some of it to the atmosphere through respiration. The carbon that remains as plant tissue is then consumed by animals or added to the soil as litter when plants die and decompose. The primary way that carbon is stored in the soil is as SOC.
The degradation of one-third of the world's soils has already released up to 78 gigatons of carbon into the atmosphere. Conventional farming or highly mechanized agriculture with a monoculture of crops and extensive use of chemical fertilizers, herbicides, fungicides, nematodes to promote plant growth has resulted in the degradation of more than 30 percent of the world's soil, according to the UN Food and Agriculture Organization.
Also read: Opinion | The story behind my roti-maker
If degradation of soil and business-as-usual agricultural practices continues, it is likely that more carbon will be lost to the atmosphere than can be sequestered into the soil. Carbon dioxide is the principal greenhouse gas contributing to global climate change so it must be sequestered.
Carbon sequestration is the long-term storage of carbon in oceans, soil, vegetation (especially forests), and geological formation. It includes the removal of carbon dioxide from the atmosphere in the form of SOC.
Regenerative agriculture or traditional agricultural practices help to enhance carbon matter in the soil. Some recommended management practices (RMP) that leads to soil organic carbon sequestration are mulch farming, conservation tillage, agroforestry, diverse cropping systems, cover crops, and integrated nutrient management, including the use of manure, biosolid, improved grazing and forest management.
Improved soil organic carbon is the best for plant growth and increased food production: it is a win-win for both world food security and global climate change.
We thus see a close relationship between soil carbon sequestration and world food security, which can neither be overemphasized nor ignored.
It is said that the soil carbon pool is 3.3 times the size of the atmospheric carbon pool and 4.5 times what animals and plants can store. Also, the soil has the potential to offset 5-15 percent of global fuel emissions.
There is an urgent need to transform our present land management practices and conventional agriculture to sustainable land management and regenerative organic agricultural practices so that our soil becomes fertile and healthy.
Healthy and fertile soil can store the maximum amount of carbon and can contribute to climate change adaptation and mitigation. Soil scientist and winner of World Food Price (2020) Rattan Lal says carbon in soil is like water in a cup. If we drink some of it, we can again fill up the cup.
The author is a student at the Institute of Forestry, Pokhara Campus
