The top 30 centimeters of the world's soil contains three times as much carbon dioxide as all plants. However, if we also look at the layer from 30 cm to 1 meter deep, we find that the amount of carbon is stored there. According to Australian soil scientist Christine Jones, we often ignore this important carbon storage.
Jones argues that soil is the world's most important store of carbon. Paying attention to the top layer of soil is good, but she believes there is more to be gained by encouraging carbon storage, preferably in stable forms, in deeper soil layers. Carbon is stored there in the form of humus over many years, sometimes centuries.
In the climate agreements reached in Kyoto at the time, the focus was on storing carbon in the upper 30 cm layer. According to Jones, humus can play a more important role in deeper layers. She offers tips on strategy that can increase storage space in that tier.
First and foremost, Jones sees benefits in allowing more diversity in permanent grasslands. These grasslands last longer and ensure maximum biological activity in the soil with different root properties. According to Jones, this life plays a major role in storing carbon.
The second part of Jones' strategy is to apply more environmentally friendly fertilizers to the soil. By replacing nitrogen and phosphate fertilizers with organic ones, the farmer encourages plants to enter into symbiosis with soil life, especially with mycorrhizal fungi. Most plants intensify symbiosis with these fungi when only a few water-soluble sources of free nitrogen and phosphate are present.
Mycorrhizal roots constitute a significant mass of soil organic carbon. They are sensitive to too much salty fertilizer and to soil cultivation. Jones sees a sharp decline in organic matter in Australian soils since the advent of industrial agriculture. “That's why we have to rethink grass-rich grasslands versus one-sided grasslands,” she says.
The severe soil degradation in the drier parts of the world cannot be directly compared to the situation of Dutch soils. Jones notes that the side effects of having more organic carbon in deeper soil layers are important everywhere. During heavy rains and droughts, soil carbon contributes to plant growth and reduces the risk of crop failure, both by draining water better during heavy rains and returning it to the top in water shortages.
“Thinker. Coffeeaholic. Award-winning gamer. Web trailblazer. Pop culture scholar. Beer guru. Food specialist.”