There is hardly a better place to test a fertiliser than a grass tennis court. A perfect lawn, grass-green, resistant and trimmed to the millimetre, needs the perfect food. Up until now, this food has been provided by artificial fertilisers. Now, the aquatic research institute Eawag, the spin-off Vuna and the operators of Switzerland's first public grass tennis court want to show that locally produced urine fertiliser can do the job. Today, the Urine Express is making a stopover in Biel in order to demonstrate the procedure. Artificial fertiliser has to be imported. Production and transport consume a lot of energy, and artificial fertilisers usually contain harmful substances such as the heavy metals cadmium or radioactive uranium, in addition to the useful ones. "Urine instead of uranium", says Bastian Etter, Managing Director of Vuna and former Eawag researcher who was instrumental in the development and certification of the urine fertiliser.

So, will the sacred lawn at Wimbledon soon be fertilised with fertiliser made from the pee of stadium spectators? "Who knows?", says Etter. Many things are possible, for after three weeks of use in Biel at http://www.tennis-champagne.ch the Urine Express will continue its journey to the next place of use and thus contribute to sustainable fertilisation not only of lawns, but also gardens, parks and even vegetables.