London, Nov. 30: Human excreta could have a key role in securing future food security, helping prevent a sharp drop in yields of crops such as wheat due to a shortage of phosphorus inputs, a UK organic body said on Monday.
“It is estimated that only 10 per cent of the three million metric tonnes of phosphorus excreted by the global human population each year are returned to agricultural soils,” Britain’s largest organic certification body, the Soil Association, said.
An adequate supply of phosphorous is essential for seed formation, root development and maturing of crops. “We are completely unprepared to deal with the shortage of phosphorus inputs, the drop in production and the hike in food prices that will follow,” the Soil Association said in its report Heavy Metals
Historically in Europe, phosphorus was returned to land through the application of animal manure and human excreta but from the mid-nineteenth century, it was replaced by phosphate mined in distant places.
“Heavy metal levels have declined in recent years and are now low enough for the organic movement to re-consider allowing treated sewage sludge to be used,” the report said. It also called for a reduction of the amount of meat in human diets to reduce demand for mined phosphorus.
“This is because the efficiency with which phosphorus inputs are converted into dietary phosphorus is much higher in vegetable-based products than livestock products,” it said.