Terra preta are fascinating black soils found dotted across the Amazon forest. They only cover a small area, but have amazing fertility and are rich in organic compounds - they are often islands of fertility in a sea of general highly infertile and heavily leached tropical forest oxisols. The original terra preta soils are thought to have been created 1-2000 years by pre-Colombian Amazonians through low-heat, smouldering, domestic fires that were used for cooking and heating.
We have just published (in Plant Ecology and Diversity) the first comprehensive description of the carbon cycle on a terra preta, and compare with a nearby forest growing on infertile oxisols. The data were collected over the period 2005-2011, at the Caxiuana National Forest in collaboration with the University of Para (led by Antonio Lola da Costa) and the Museu Paraense Emilio Goeldi (led by the late Samuel Almeida).
We find that the forest growing on terra preta soil is a bit more productive (but not as much as we expected), and more efficient in turning photosynthate into biomass. Individual trees grow more rapidly, but there are fewer trees in the plot (possibly a legacy of the fact that this is an abandoned agroforest rather than a pristine old-growth forest).
The paper is part of a suite of papers we have published in a special issue of Plant Ecology and Diversity. The papers are slowly appearing online over the next few months. The terra preta site is part of our global intensive forest monitoring network, GEM.
Doughty C.E. , Metcalfe D.B. , da Costa M.C. , de Oliveira A.A.R , Neto G. F.C. , Silva J.A. , Aragão L.E.O.C , Almeida S.A. , Quesada C.A., Girardin C.A.J. , Halladay K. , da Costa A.C.L. & Malhi Y. (2013) The production, allocation and cycling of carbon in a forest on fertile terra preta soil in eastern Amazonia compared with a forest on adjacent infertile soil DOI: 10.1080/17550874.2013.798367
Yadvinder Malhi is an ecosytem ecologist and Professor of Ecosystem Science at Oxford University