Carbon capture in soil: A bridge to the future
The bill for shifting food production in a more soil-friendly direction cannot be sent only to farmers, says the renowned soil researcher Rattan Lal. He suggests paying farmers to build soil health.
Hege Sundet, NLR Østafjells
- Life in the soil, the formation of soil, and life above ground are all interconnected. A teaspoon of soil can contain more species than the entire Amazon, says Rattan Lal. He is a professor of soil science and director of the Carbon Management and Sequestration Center at Ohio State University in the USA. For many decades, Lal has been researching soil and estimating the global loss of topsoil. He visited Norway in 2019 with an invitation from the Soil Association in Ås and gave an inspiring presentation about “Managing Soil Carbon for Food and Climate”.
The great paradox
With its natural functions intact, soil helps maintain water, climate, and nutrient cycles. It is the foundation for all terrestrial life. The great paradox is that our existence and everything we do depends upon ecosystem services from soil, but at the same time, our way of life threatens the soil on a global scale. The professor is clear:
- Without soil there is no life, and without life – no soil.
The negative spiral
The global depletion of soil begins with a method of agriculture in which crops are harvested, but little or nothing is given back to the soil. The resulting loss of organic material, nutrients, and organisms leads to weakening of the soil’s structure. Structure is essential to the proper functioning of soil. Loss of structure leads to increased erosion and widespread compaction. When the physical environment no longer functions as a habitat, functional groups of organisms disappear. Key processes in the soil come to a halt. Among other things, this can result in the soil having reduced capacity to hold water or allow precipitation to flow through the soil profile. In areas where the soil is severely damaged, this in turn leads to poverty, hunger, refugees and war.
- The deterioration of soil is as great a threat to world peace as nuclear weapons, says Rattan Lal.
Carbon farming is the way forward
Lal estimates that it is technically possible to sequester 2.5 gigatons of carbon in the soil each year. Atmospheric CO2 can be transferred into the soil by plants, either as plant remains or in the form of organic substances. The captured carbon can then be stored long-term as a component of the soil. This is referred to as ‘carbon sequestration’. With regards to the physical, chemical, and biological aspects of soil, organic matter content is fundamentally important for self-regulation of soil.
The way we approach agriculture is critical to soil health, according to Rattan Lal. Agronomic measures that protect soil and ensure greater carbon capture are important. When the soil’s organic carbon content is built up and soil life thrives, soil health is also improved. Continuous cover, minimal disturbance of the soil, diverse crop rotations and organic fertilization are the ways to go, claims Lal.
Not the farmer’s bill
The value and cost of soil-friendly management must be built into every fruit and vegetable eaten, into the bread, into each cup of water that is used, into the air we breath, and into the cultural landscapes, Lal points out.
There is a cost to changing practices, and that bill cannot be paid by the farmer. One possible solution is to pay the farmer to build soil health. Whether this is in prices on goods, as part of a business model or subsidy can vary.
Soil welfare is compatible with food security
Lal cites a proverb; “When diet is wrong, medicine is of no use; when diet is correct, medicine is of no need.” In other words, we must address the root of the problem. This means that taking care of organic matter and soil life, along with facilitating carbon sequestration in soil, is the only viable way forward. We cannot continue the current path.
The main argument for continuing intensification of agriculture is the increasing world population and the corresponding demand for more food. Lal points out that at least one third of the food currently produced is simply thrown away. The solution to sustainably meeting the nutritional needs of ten billion people by 2050 is organic intensification of agriculture and methods that rebuild soil health, not cultivation of more land, says Lal.
Knowledge and education are the keys
Education and training will enable us to change course, explains Lal. This is why it is very important to incorporate knowledge of soil health and wider perspectives into education at the universities, high schools, natural resource management schools, agricultural extension services and for the public in general. The key to overcoming the challenges we are facing today is to incorporate this knowledge into the farmers practice, and that the farmers will be rewarded for their efforts, says Lal.
His professional research interests include soil carbon sequestration for food and climate security, conservation agriculture, principles and practices of soil erosion control, soil structure and carbon dynamics, eco-intensification of agroecosystems, soil restoration, fate of soil carbon transported and redistributed over the land scape, and sustainable management of world soil resources.