Weed composition and cover after three years of soil fertility management in the central Brazilian Amazon: Compost, fertilizer, manure and charcoal applications
JULIE MAJOR,1 * CHRISTOPH STEINER,2 ANTONIO DITOMMASO,1 NEWTON P.S. FALC
Mollisols are known to contain stable, black humus components which originate from
charred or coal-derived particles. As such black carbon (BC) significantly affects soil
fertility and interferes with models on soil organic matter dynamics, an accurate prediction of BC input into soils and an elucidation of the mechanisms of BC turnover
is essential. The main aims of this study were (i) to identify the sources of BC in the
Mitteilungen der Deutschen Bodenkundlichen Gesellschaft (1997) 85: 237 - 240
Black carbon (BC) is formed during incomplete combustion of biomass. Being highly resistant to microbial and chemical oxidation, it is considered to be a significant sink in the global carbon cycle. Most likely, it is also a source of stable aromatic carbon in soils.
Terra Preta (do indio) is a black earth-like anthropogenic soil with enhanced fertility due to high levels of soil organic matter (SOM) and nutrients such as nitrogen, phosphorus, potassium, and calcium embedded in a landscape of infertile soils (see soil profiles below). Terra Preta soils occur in small patches averaging 20 ha, but 350 ha sites have also been reported. These partly over 2000 years old man made soils occur in the Brazilian Amazon basin and other regions of South America such as Ecuador and Peru but also in Western Africa (Benin, Liberia) and in the savannas of South Africa. Terra Preta soils are very popularby the local farmers and are used especially to produce cash crops such as papaya and mango, which grow about three times as rapid as on surrounding infertile soils.