Ancient fertilizer technique could help poor farmers, store carbon

A Canadian researcher is hoping to improve the lives of rural farmers in developing nations by helping them tap into the growing carbon market and re-connect with a technology used to enrich soils in the Amazon thousands of years ago.

A Canadian researcher is hoping to improve the lives of rural farmers in developing nations by helping them tap into the growing carbon market and reconnect with a technology used to enrich soils in the Amazon thousands of years ago.

Marco Rondon, who works with the Rural Poverty and Environment program at the federal government's International Development Research Centre in Ottawa, is helping co-ordinate a meeting in July that would bring together companies, groups representing farmers and other stakeholders to develop a carbon trading scheme that will also reduce hunger and poverty.

Rondon said Wednesday that industry in the developed world has been aggressively pushing for the inclusion of biochar, a fertilizer made from the charcoal of partially combusted organic materials, in carbon trading.

What is biochar?

Biochar is charcoal made from the partial combustion of organic materials. It contains high levels of organic carbon and enriches soils by adding nutrients such as potassium and calcium and boosting the soil's ability to retain water and nutrients. It also helps neutralize acidic soils such as those found in the Amazon. The soil becomes a more welcoming environment for fungi and bacteria, which boost the amount of nitrogen and other nutrients available to plants. Carbon in the form of biochar remains stable within the soil for thousands of years. Studies show that the addition of biochar improves crop yields, especially in poor soils.

That is because the material keeps carbon in the ground for millennia, while regular decomposition of organic material releases the carbon back into the atmosphere within 20 or 30 years, Rondon said at a presentation in Ottawa Wednesday. Producing biochar has also become a way for companies in the developed world to profit from waste such as chicken dung and rice husks.

The total amount of carbon stored in soils is currently about twice the amount of carbon stored in the atmosphere, Rondon said.

"If we were able to increase the amount of carbon in soils by 100 per cent — double that amount — that will have a huge possibility to manoeuvre in reducing the carbon dioxide in the atmosphere."

He thinks the greatest potential of the technology, however, is not as a carbon sink, but to help farmers who work the poorest soil in the poorest countries in the world.

"There are millions of people who depend on those degraded lands for making a living," he said. "They are not having an easy life there."

Amazon soil acidic, nutrient-poor

Biochar was once used by ancient farmers in the Amazon, where the natural soil is acidic and nutrient poor, Rondon said. They produced plots of terra preta, fertile soils enriched with charcoal, fish bones and fruit husks. Some of the plots have been found to be 7,000 years old. The original terra preta is still sold in markets today for use in gardens.

Biochar is also still used to enrich soils all over the world, but is no longer within the reach of many rural farmers in the poorest parts of South America, Rondon said. That is because the soils there are too poor to produce the raw materials for biochar and they don't have the financial resources to bring the raw materials or biochar from other places. Poor soils are the ones that show the greatest increase in productivity once biochar is introduced.

But Rondon sees the push to include biochar in carbon markets as an opportunity for the farmers.

"The emerging and growing carbon trading could be potentially this source of income that is needed."

Rondon has been talking to companies in the hopes of getting them to invest up-front in the raw materials for biochar projects that may not yield carbon credits immediately. For example, he has approached Air Canada, which currently sells carbon credits to passengers who want to offset the greenhouse gas emissions they produce by flying.

He is hoping to start with some small pilot projects that the International Development Research Centre would monitor.

Currently, he said, there are about two billion hectares of degraded farming soils in the world and about one billion people depend on that land to survive.

"Restoring the quality of those soils … will have durable effects not only for people today but coming generations," he said.

However, he added that caution and further study are needed before the use of biochar can be applied to carbon storage on a large scale, as concerns remains as to whether removing plant residues for biochar production could have a negative impact on the soil and whether use on a worldwide scale could affect nutrient and water cycles and soil organisms.

In addition, he has some concerns that production of biomass for biochar could wind up displacing food production. In recent years, many farmers began raising crops to produce ethanol instead of food due to government incentives for biofuels, and that was blamed for a sharp increase in worldwide food prices.