You must have heard human waste to be used as soil fertility boosters. But scientists suggest, it could be the next big weapon in the fight against climate change.
Research indicates that human waste can not only boost fertility and organic structure of soil but can also increase carbon retention in the soil. Bio-solids contain the major nutrients nitrogen and phosphorus, but also micro-nutrients and trace minerals.
“Our research shows that if applied to agricultural soils or re-vegetation projects, bio-solids – as well as increasing soil fertility and boosting plant growth – can lock up carbon,” Professor Nanthi Bolan from the University of South Australia said.
He further added, “Biosolids contain nitrogen and other nutrients for crop growth, organic matter to improve soil structure, and non-degradable forms of carbon that will stay in the soil for a long time.”
Scientists believe that the big issue with bio-solids is the cost of transporting them to where they will be used and spreading them on the soil.
Bolan said that the research indicates this can be offset not only by the boost to fertility and soil organic structure but also by its ability to increase carbon retention in the soil.
“In other words you could earn carbon credits by using treated human waste as a soil improver – which would pay for part of the cost of transporting and distributing it,” said Bolan.
The amount of carbon that can be locked up depends on several variables . These variables range from how the bio-solids were stabilized at the sewage works, the type of crop they fertilize, and the levels of iron and aluminium in the soils, which combine with, and consequently lock up, the carbon in bio-solids.