TY - JOUR

T1 - The 'Terra Preta' phenomenon:

T2 - A model for sustainable agriculture in the humid tropics

AU - Glaser, Bruno

AU - Haumaier, Ludwig

AU - Guggenberger, Georg

AU - Zech, Wolfgang

N1 - Funding information: We are indebted to Wenceslau Teixeira for assistance with field work, Petra Gros for black carbon analysis, four anonymous reviewers for critical comments on the manuscript, and the German Research Foundation for financial support (DFG Gu 406–1/1,2). The experiments comply with the current laws of Brazil and Germany where the experiments were performed.

PY - 2001/1/24

Y1 - 2001/1/24

N2 - Many soils of the lowland humid tropics are thought to be too infertile to support sustainable agriculture. However, there is strong evidence that permanent or semi-permanent agriculture can itself create sustainably fertile soils known as 'Terra Preta' soils. These soils not only contain higher concentrations of nutrients such as nitrogen, phosphorus, potassium and calcium, but also greater amounts of stable soil organic matter. Frequent findings of charcoal and highly aromatic humic substances suggest that residues of incomplete combustion of organic material (black carbon) are a key factor in the persistence of soil organic matter in these soils. Our investigations showed that 'Terra Preta' soils contained up to 70 times more black carbon than the surrounding soils. Due to its polycyclic aromatic structure, black carbon is chemically and microbially stable and persists in the environment over centuries. Oxidation during this time produces carboxylic groups on the edges of the aromatic backbone, which increases its nutrient-holding capacity. We conclude that black carbon can act as a significant carbon sink and is a key factor for sustainable and fertile soils, especially in the humid tropics. In the lowland humid tropics, highly weathered soils of low fertility and sustainability predominate (Tiessen et al. 1994). Numerous studies have been conducted to investigate the relationship between soil fertility and land-use practices (e.g. Guggenberger et al. 1994; Tiessen et al. 1994; Kleinman et al. 1996; Westerhof 1998; Thomas and Ayarza 1999). One of the major problems of sustainable agriculture in the humid tropics is the rapid decomposition of organic matter (Zech et al. 1990) due to the high temperatures, large amounts of precipitation, and the lack of stabilizing minerals. Mean residence times of less than 4 years have been calculated for particulate organic matter in undisturbed soils of the Venezuelan rain forest (Tiessen et al. 1994). Inorganic fertilizers are often too expensive for the indigenous population to use and their effect is only short-lived due to the low nutrient-holding capacity of the poor soils.

AB - Many soils of the lowland humid tropics are thought to be too infertile to support sustainable agriculture. However, there is strong evidence that permanent or semi-permanent agriculture can itself create sustainably fertile soils known as 'Terra Preta' soils. These soils not only contain higher concentrations of nutrients such as nitrogen, phosphorus, potassium and calcium, but also greater amounts of stable soil organic matter. Frequent findings of charcoal and highly aromatic humic substances suggest that residues of incomplete combustion of organic material (black carbon) are a key factor in the persistence of soil organic matter in these soils. Our investigations showed that 'Terra Preta' soils contained up to 70 times more black carbon than the surrounding soils. Due to its polycyclic aromatic structure, black carbon is chemically and microbially stable and persists in the environment over centuries. Oxidation during this time produces carboxylic groups on the edges of the aromatic backbone, which increases its nutrient-holding capacity. We conclude that black carbon can act as a significant carbon sink and is a key factor for sustainable and fertile soils, especially in the humid tropics. In the lowland humid tropics, highly weathered soils of low fertility and sustainability predominate (Tiessen et al. 1994). Numerous studies have been conducted to investigate the relationship between soil fertility and land-use practices (e.g. Guggenberger et al. 1994; Tiessen et al. 1994; Kleinman et al. 1996; Westerhof 1998; Thomas and Ayarza 1999). One of the major problems of sustainable agriculture in the humid tropics is the rapid decomposition of organic matter (Zech et al. 1990) due to the high temperatures, large amounts of precipitation, and the lack of stabilizing minerals. Mean residence times of less than 4 years have been calculated for particulate organic matter in undisturbed soils of the Venezuelan rain forest (Tiessen et al. 1994). Inorganic fertilizers are often too expensive for the indigenous population to use and their effect is only short-lived due to the low nutrient-holding capacity of the poor soils.

UR - http://www.scopus.com/inward/record.url?scp=0035076148&partnerID=8YFLogxK

U2 - 10.1007/s001140000193

DO - 10.1007/s001140000193

M3 - Article

C2 - 11302125

AN - SCOPUS:0035076148

VL - 88

SP - 37

EP - 41

JO - NATURWISSENSCHAFTEN

JF - NATURWISSENSCHAFTEN

SN - 0028-1042

IS - 1

ER -