Researchers in Finland grew beets as an experiment using sustainable fertilizer -- human urine, Scientific American reported on Friday. Surendra Pradhan and Helvi Heinonen-Tanski, environmental scientists at the University of Kuopio used a combination of urine and wood ash, which they found worked just as good as traditional mineral fertilizer. "It is totally possible to use human urine as a fertilizer instead of industrial fertilizer," said Heinonen-Tanski, whose group used urine to also grow cucumbers, cabbage and tomatoes. Urine contains nitrogen, potassium and phosphorus, which are nutrients plants need to thrive. There is, of course, a steady supply of this man-made plant food: an adult on a typical diet urinates enough in a year to full three standard bathtubs. Despite a small group of organic gardeners in the U.S. and Europe already fertilizing with urine at home, using it to fertilize in large-scale farming may never happen because it would involve drastically remodeling sewage systems in order to collect and transport liquid waste.

(Scientific American, July 23, 2010)

(http://www.scientificamerican.com/…)