If we stopped releasing carbon from the soil into the atmosphere and captured it instead, then the serious problem of global warming could be solved.
International soil scientist John Baker says, in relation to soil, there’s more “carbon going out than coming in” and the world has reached a stage where the process must be reversed. When it is, there won’t be a problem with climate change.
Baker points out we recycle bottles and plastics but not carbon, and the time to start recycling carbon is long overdue.
“There’s more carbon dioxide in the atmosphere and less in the soil than ever before,” he says. “While the first crucial step is to grow more plants, it’s even more important to ensure the carbon that existing plants absorb from the atmosphere through photosynthesis remains in the soil.”
At the moment carbon is squandered. About 50% is lost when food is harvested, but Baker says that’s acceptable because it’s why we grow food in the first place.
But as much carbon remains as straw, stubble and roots after harvest, and if this is removed, burnt or incorporated, then most of it gets back into the atmosphere where it contributes to global warming.
“Instead, we must retain the crop residue after harvest and offer the carbon to the soil microbes. They decompose it and earthworms and other fauna take it into the soil, which enriches it,” he says.
“The future of mankind depends on harnessing the biology in the soil and making it work for us. The impact would be massive if the uneaten carbon that food crops gather globally was transferred into the soil and stayed there.”
Baker explains that only 4% of the world’s surface can grow crops. The rest is water, mountains, highways and the ever increasing urban sprawl, so it’s important to maximize the land that’s available.
“New Zealand is very effective in growing crops, but ineffective in recycling the carbon that the crops gather,” he says. “By releasing it back into the atmosphere through tillage or burning we contribute to climate change and destroy the nutrients.
“What we have to do is stop ploughing and burning and instead use low-disturbance no-tillage. It’s a no-brainer, especially when we already have the best low-disturbance, no-tillage machines in the world.”
The United Nations Food and Agriculture Organization (FAO) predicts there are only 60 harvests left in the world. After that there’ll be widespread famine with insufficient food to feed a population that will increase by 50% within 40 years.
“In fact, the lack of carbon in the soil is more scary than its presence in the atmosphere. If carbon-out continues to exceed carbon-in, some people are eventually going to starve,” Baker says.
To resolve this issue, Baker has researched, tested and built a low-disturbance no-till drill that penetrates through residue and vegetation on top of the soil to create seed slots beneath it. They sow the seed and fertilizer in separate bands at the same time. The process traps the humidity, preserves the microorganisms and soil life, and prevents the carbon from escaping.
“What we’re doing is swapping the balance so there’s more carbon-in than carbon-out. The method confronts climate change and increases the amount of food that the world produces at the same time,” he says. “It’s a win-win if ever there was one.
“The side benefit will be food that’s less expensive and land that is more sustainable. Good quality soil can produce food indefinitely because we’re recycling the carbon and enriching the soil.”