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| Author(s): |
Fabiana de Souza Cannavan
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB) |
| Defense date: | 2012-02-03 |
| Examining board members: |
Tsai Siu Mui;
Fernando Dini Andreote;
Dilmar Baretta;
Beata Emoke Madari;
Valéria Maia de Oliveira
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| Advisor: | Tsai Siu Mui |
| Abstract | |
Amazonian Dark Earth (ADE), also known as Terra Preta de Índio, present tropical A horizon, high pH, important nutrients for plant growth, high pyrogenic charcoal levels and intense biological activity when compared to its soil of origin. Soil microbial community is essential for ecosystem function, which is involved in fundamental processes such as the decomposition of organic matter, availability of nutrients to plants and the nutrient cycling. The objective of this study was to assess the structure and composition of bacterial and archaeal communities in fragments of pyrogenic charcoal (from ADE), ADE and adjacent soil (ADJ) using molecular techniques. The soils were collected in four archaeological sites (Balbina, Barro Branco, Costa do Açutuba and Hatahara), located in the central Amazon. In general, ADE presented high values of pH, P and Ca agreeing with previous results in ADE. ADE samples in Balbina, Barro Branco and Hatahara sites presented higher bacterial 16S rRNA gene copy number in comparison with ADJ soil samples. The results obtained with the fingerprinting techniques (Terminal Restriction Length Polymorphism, T-RFLP and Denaturing Gradient Gel Electrophoresis, DGGE) using the bacterial and archaeal 16S rRNA genes revealed that bacterial community structure in charcoal fragments differed significantly when compared to the ADJ soils. Using the pyrosequencing technique, the phyla Proteobacteria, Actinobacteria and Crenarchaeota were predominant in charcoal fragments. It was also observed that microorganisms from charcoal fragments may be directly related to the N and C cycles. Furthermore, the presence of these microorganisms in charcoal fragments may favor the soil microbiota and, consequently, its quality. In this context, pyrogenic charcoal can serve as an element to recover degraded areas acting as soil conditioner and a promising alternative to the management of agricultural soils. (AU) | |