Human Urine Safe, Productive Fertilizer

ByABC News
March 24, 2008, 1:33 AM

Mar. 23 -- MONDAY, Oct. 8 (HealthDay News) -- Cash-strapped farmers shouldn't look far for a source of free fertilizer, according to a new study that finds human urine to be a great source of nitrogen and other minerals.

The "yuck" factor aside, scientists who used urine to help raise a bumper crop of cabbages said the practice may not be a bad idea.

"Urine is a valuable fertilizer which poor people could use to increase yields and not contaminate their environment. It is a resource, not a pollutant, if correctly managed," said Helvi Heinonen-Tanski, leader of a research group at the University of Kuopio's Department of Environmental Sciences in Finland.

They decided to look into how human urine could be used to help farmers and at the same time save water and reduce the contamination of water resources, added Surendra K. Pradhan, a research student at the university and the study's lead author.

"It is important to areas which are not connected with wastewater treatment systems," he added.

The use of urine as fertilizer is uncommon, but it is increasing in some parts of Finland, the researchers said. It also has been used to fertilize barley and cucumbers, the study said. "We assume the nitrogen contents of human urine could be a good fertilizer for many other plants or crops," Pradhan said.

The researchers chose cabbage as a test crop, because it needs a lot of nitrogen, it is distributed worldwide, and it can be preserved as sauerkraut.

The cabbage fertilized with urine was compared with similar plots of cabbage that either went unfertilized or where commercial fertilizer was used.

At harvest, the cabbage enriched with the urine had several advantages: It was slightly larger, it grew to its maximum size more quickly, and, for most of the growth cycle, it suffered less bug damage than the commercially fertilized variety.

Cabbage from all three plots was made into sauerkraut and taste-tested by 20 panelists. Each type tasted different, but all were rated "good," the study said.