To pee or not to pee: why urine's great for compost heaps | Life and style | guardian.co.uk:
"Have you heard of a 'pee bale'? It's the latest measure adopted at the National Trust property Wimpole Hall in Cambridgeshire to both save water and ensure efficient composting.
As the name suggests, a 3m-long series of straw bales has been installed alongside the compost heaps in the walled gardens so workers (well the male ones anyway) can relieve themselves. Urine has been long-established as a free compost 'activator' (aka 'liquid gold'), because it's full of nitrogen, but there are other benefits too. Tamzin Phillips, the NT's 'compost doctor' is quoted in the press release as saying: 'What's so great about the pee bale is that it's using a natural solution to help the garden while saving flushing the loo for only when it's really necessary.'"