Hi all,

After lurking some time, and enjoying the ng as a rich information source,
time for a little contribution.

'The Secret of El Dorado' BBC Two, Thursday 19 December, 9pm
text summary at:
http://www.bbc.co.uk/science/horizon...eldorado.shtml

"Bruno Glaser, from the University of Bayreuth, has found that terra preta
is rich in charcoal, incompletely burnt wood. He believes it acts to hold
the nutrients in the soil and sustain its fertility from year to year. This
is the great secret of the early Amazonians: how to nurture the soil towards
lasting productivity. In experimental plots, adding a combination of
charcoal and fertiliser into the rainforest soil boosted yields by 880%
compared with fertiliser alone."

regards,
Laurents