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Whereas many researchers still approach Terra Preta (TP) as a soil category, new evidence suggests that TP refers to a directional grading of soil property changes (i.e., color, pH, nutrients, etc.) within human-made soils, originating from human activities in pre-Columbian times. Currently, most TP research focuses on the Brazilian part of the Amazon basin, but only little information is available on TP soils in the Colombian Amazon. Here, we sampled four TP and surrounding soils in the Colombian Amazon region at different soil depths and analyzed them for (i) general soil properties such as color, pH and texture, (ii) soil organic carbon and black carbon (BC) contents, the latter using benzene polycarboxylic acids as molecular marker, (iii) phosphorus availability based on sequential fractionation, and (iv) microbial residue contents using amino sugars. Our data from Colombia’s middle Caquetá River and Leticia confirmed that SOC, BC, and total P were present in significantly higher concentrations in the TP areas than the surrounding soils, while pH values and microbial residue contents were unchanged. The enrichment of P forms comprised both easily extractable and stable P pools, which both dominated to a different degree, both in TP and adjacent soils. The different degree of SOC, BC and P enrichment suggests different amounts of waste disposal by the ancient populations at different TP sites, now warranting further research for reconstructing ancient population sizes from TP chemical analyses.
Juan Orozco-Ortiz; Clara Peña-Venegas; Sara Bauke; Christian Borgemeister; Ramona Mörchen; Eva Lehndorff; Wulf Amelung. Terra Preta Properties in Northwestern Amazonia (Colombia). Sustainability 2021, 13, 7088 .
AMA StyleJuan Orozco-Ortiz, Clara Peña-Venegas, Sara Bauke, Christian Borgemeister, Ramona Mörchen, Eva Lehndorff, Wulf Amelung. Terra Preta Properties in Northwestern Amazonia (Colombia). Sustainability. 2021; 13 (13):7088.
Chicago/Turabian StyleJuan Orozco-Ortiz; Clara Peña-Venegas; Sara Bauke; Christian Borgemeister; Ramona Mörchen; Eva Lehndorff; Wulf Amelung. 2021. "Terra Preta Properties in Northwestern Amazonia (Colombia)." Sustainability 13, no. 13: 7088.
Bioturbation involves the incorporation of residues from the surface soil into the subsoil; however, common small soil ‘bioengineers’, such as earthworms or termites, are unlikely to transport human artifacts to deeper soil horizons. However, such artifacts occur in the deeper soil horizons within Amazonian Anthrosols (Terra Preta). Here we test the assumption that such tasks could be carried out by fly larvae, which could thus play a crucial role in waste decomposition and associated soil mixing under tropical conditions. We performed two greenhouse experiments with sandy substrate covered with layers of organic waste, ceramic fragments, and black soldier fly larvae (BSFL) (Hermetia illucens (L.) (Dipt.: Stratiomyidae)). We used in-situ images to assess the rate of bioturbation by BSFL, and then designed our main study to observe waste dissipation (reduction of organic carbon and phosphorus contents from waste model trials with and without charcoal) as related to larval-induced changes in soil properties. We found that the bioturbation of macroinvertebrates like BSFL was able to bury even large (> 5 cm) ceramic fragments within hours, which coincided with high soil growth rates (0.5 cm h-1). The sandy soil was subsequently heavily enriched with organic matter and phosphorus originating from organic waste. We conclude that BSFL, and possibly other fly species, are important, previously overlooked soil ‘bioengineers’, which may even contribute to the burial of artifacts in Anthrosols and other terrestrial waste dumps.
Juan M. Orozco-Ortiz; Sara L. Bauke; Christian Borgemeister; Eva Lehndorff; Wulf Amelung. Bioturbation by black soldier fly larvae—Rapid soil formation with burial of ceramic artifacts. PLOS ONE 2021, 16, e0252032 .
AMA StyleJuan M. Orozco-Ortiz, Sara L. Bauke, Christian Borgemeister, Eva Lehndorff, Wulf Amelung. Bioturbation by black soldier fly larvae—Rapid soil formation with burial of ceramic artifacts. PLOS ONE. 2021; 16 (6):e0252032.
Chicago/Turabian StyleJuan M. Orozco-Ortiz; Sara L. Bauke; Christian Borgemeister; Eva Lehndorff; Wulf Amelung. 2021. "Bioturbation by black soldier fly larvae—Rapid soil formation with burial of ceramic artifacts." PLOS ONE 16, no. 6: e0252032.