Terra preta nova - Where to from here?

Abstract

Terra preta de índio (also called Amazonian Dark Earths or ADE [a term introduced by Woods and McCann 1999]) is one of the most fascinating and intriguing re-discoveries in modern soil science. Its study led to a shift in our understanding about pre-Columbian civilizations (Neves et al. 2003) and provides a plausible explanation for a much greater carrying capacity of the highly weathered Amazonian soils than hitherto anticipated. ADE soils have sustained a high fertility (Lehmann et al. 2003b) as expressed in their elevated nutrient availability and organic matter contents for hundreds to thousands of years after they were abandoned by the populations that caused their appearance. Could it be that these soils were purposefully created by Amerindian populations to improve the productivity of the soil as suggested by some (Woods et al. 2000; Neves et al. 2003)? And, could the emergence of ADE even be the reason for the development of civilization in the Amazon with more numerous and more complex societies than was anticipated until recently (Heckenberger et al. 2003)? How did they do it? The answer to that question may also teach us valuable lessons for sustainable landuse management in our time. However, the lessons that ADE can teach us do not hinge upon the fact whether or not the Amazonian populations intentionally created these fertile soils for improving soil productivity for agriculture or whether they are an accidental byproduct of habitation. We can even draw the most important conclusions without ever knowing how ADE was actually created. These lessons can be gleaned from the properties of ADE today and the fact that these were in some way 'created' at a particular point in history a long time ago. As we can understand it today, the most important aspect of ADE is its high nutrient availability and high organic matter content. The goal of the recent efforts in ADE research has therefore been to find the answer to the question how it is possible that these favorable properties can still be observed after such a long period of time. What is unique about ADE that explains its sustainable productivity? Some of these lessons will be discussed in the first part of this chapter. In the second part, one of these lessons will be discussed in more detail with respect to the development of a new soil and biomass management approach: biochar agriculture for environmental management. © Springer Science + Business Media B.V. 2009.