For nearly two decades, researchers in the soil science community have studied and estimated the potential of sequestering carbon in soil organic matter. As a result, about 10,000 years of cultivated agriculture has reduced global soil carbon to an amount equivalent to more than a decade of the present rates of industrial emissions. Furthermore, through changing agricultural techniques, it is proposed much of this carbon can be restored to domesticated soils and thus serve as a powerful tool to mitigate climate change, providing a broader timeframe for society to decarbonize. Soil carbon sequestration is, therefore, a critical method to consider.
Sequestering carbon in Soil organic carbon or SOC has been suggested as one way to mitigate climate change by reducing atmospheric carbon dioxide. The argument is that small increases in SOC over vast areas in agricultural and pastoral lands will significantly reduce atmospheric carbon dioxide. However, for the reduction to be long-lasting, the organic matter must be in the more stable or resistant fractions.
Understanding Soil Carbon Sequestration
In simple terms, soil carbon sequestration occurs when plants capture and store atmospheric carbon dioxide (CO2) in the soil layer, increasing the quantity of carbon in soil stocks. As a result, decaying plant matter and its carbon become part of the soil for a while before it is disintegrated by microbes, releasing the carbon back into the atmosphere.
The duration carbon stays in the soil before going back to the atmosphere varies significantly depending on various factors. For example, changing the soil structure by converting grasslands and forests to farmland can quickly release much of the carbon back into the atmosphere.
Some Facts to Ponder
It is estimated that the past thousands of years of agricultural practice have released almost 133 billion metric tons of CO2 from the soil into the atmosphere. It is more than three times the carbon as all human activities emitted in 2019. Cultivated soils have lost up to 70% of their original organic carbon in some places. Changing how we farm can restore some of that carbon to the soil.
How does Carbon Sequestration in Soil Work?
In agricultural ecosystems, soil carbon sequestration is also known as carbon farming which includes the adoption of farmland management practices and activities that facilitate either the absorption of more carbon by the soil or the increased retention of carbon already existing in the farmlands.
The addition of carbon into the soil occurs in two different ways and in two other forms. The first one is the more common process involving converting CO2 from the air into Soil Organic Carbon (SOC) in the soil. Plants make food in the presence of sunlight and atmospheric CO2. The food thus produced is converted into sugars (made up of carbon) stored in the plant’s tissues. Forests trap carbon in this form for decades or even centuries. However, short-lived farmland crops free carbon into the soil after they die and decay.
Despite increasing opportunities for agricultural practitioners to receive payments for sequestering carbon in their soils, several questions and challenges still need to be solved. Therefore, we seek to address some common questions farmers raise about soil carbon sequestration. Visit www.soiloptix.com to know more.