Rising level of carbon dioxide in the air and worsening climate change are well recognised facts now. Apparently burning fossil fuels is the main reason but soil is actually another significant source of carbon emissions. Changing forests into agricultural lands, and misusing the lands by excessive tillage, fertilization as well as pesticide applications both speed up the oxidation of the carbon stored in soil, resulting in significant carbon emissions. Therefore, apart from reducing the use of fossil fuels, letting the carbon in the atmosphere go back to soil is also important.
The earth has 5 natural carbon pools, namely (ranging from the highest carbon storage to lowest): oceans, fossil, soil, atmosphere and terrestrial biomass. It is surprising that soil itself holds more carbon than the atmosphere and terrestrial biomass added together. Over half of the soil carbon is in organic form. Though massive soil carbon has been lost to the air in the past, soil could also be seen as a huge potential to take back the carbon, as long as the soil is taken care of in the right way.
Organic carbon in soil not only balance the amount of carbon in the air, it is also the foundation of all the functions that soil performs. Sufficient soil organic carbon ensures high quality of crops, high productivity, rich farmland biodiversity, high water and nutrient retention, reduced soil erosion, etcl. These are crucial to all lives including us.
There has been many initiatives and actions internationally that promote soil carbon sequestration. Food and Agriculture Organization of the United Nations (FAO) proposed “climate-smart agriculture” in 2013 to highlight the connections between agriculture and climate, and 2015 was designated as the International Year of Soil to further raise the awareness on soil; French government also announced the commencement of “4 per 1000” Initiative in Paris COP21, suggesting all farmlands increase their organic carbon content at 0.4% annually, which is now gaining momentum with growing support from different countries and organizations. Soil carbon sequestration is actionable now and here, not another false promise regarding the big climate issue.