Highly fertile, anthropogenic soils in the Amazon (Terra Preta; Amazonian Dark Earth) challenge conventional theories on environmental limitation in the Amazonian basin. These improved soils (and their co-evolved crops) offer a major inspiration for (re-)creating soils for sustainable agriculture and climate change mitigation through carbon sequestration.
Lowland Amazonia is threatened by high rates of environmental degradation, caused by deforestation for agricultural expansion. Large (cattle) and small-scale practices (poverty-driven slash-and-burn agriculture) threaten Amazonian ecosystems. Both kinds of practices are intimately connected. This impact on tropical forests demonstrates the need for sustainable agricultural practices, as current practices are often not sustainable, The low productivity of the system forces agriculturalists to move to new sites. Low productivity is related to the inherent low fertility of most Amazonian soils.
Knowledge about how to transform poor soils into fertile, productive soils existed among the peoples of the Amazon. These anthropogenic soils, recognised by abundant presence of charcoal resulting in their dark colour, high amounts of phosphorus and calcium, and signs of human influence, are known as Amazonian Dark Earth (ADE) or Terra Preta do Indio (TP). These soils are remnants of ancient, pre-Columbian societies and were generally created between 3000 and 500 years BP. Today productivity of Terra Preta is still higher than the surrounding soils. Terra Preta has therefore been described as a model for sustainable and productive agriculture in the humid tropics. Ultimately this could allow (semi-)permanent agriculture and reduce poverty-driven deforestation that is rampant in the Amazon.
This INREF-funded programme aims to:
- understand conditions under which Terra Preta originated, both from the biophysical and socio-economic side;
- understand the institutional and policy dimensions related to actual use and potential future use of such fertile soils, including the creation of new soils;
- link actual perception and use of these soils for various agricultural purposes, ranging from annual and biannual cropping systems to agroforestry, to biophysical properties and socio-economic conditions (markets);
- contribute to the creation of soils that allow sustainable and productive agriculture in the Amazon, using the functioning of Terra Preta as a source of inspiration, while simultaneously contributing to climate change mitigation through carbon sequestration;
- contribute to and maintain the functioning of a network of Latin American Terra Preta researchers;
- use the conceptualisation of Terra Preta as socially constructed soils to reflect on (and change) actual scientific discourses and practices, both in research and education. Research will take place in three countries: Bolivia, Brazil, and Colombia.
The Terra Preta programme is an interdisciplinary programme that takes a diachronic approach (origin, present use, and future creation of those soils) from a perspective that recognises the hybrid nature of several major categories in the natural and social sciences.
The programme was officially launched in 2010 with the appointment of a post-doc, dr Marielos Peña Claros. In January, 2011 6 PhD students from Colombia and Brazil arrived. Early 2011 three further PhD students will join the programme. A first paper on the carbon and nutrient flows in Terra Preta soils, based on element stoichiometry and feedback processes was published by Van Hofwegen et al. (2009).
The PhD students returned to Bolivia, Brazil and Colombia in the summer of 2011 to start field work. Field work has been executed in close collaboration with Embrapa, and the site at Caldeirão. An international workshop has taken place in May 2011, and will be repeatedly annually.