| Full text | |
| Author(s): |
Cenciani, Karina
[1]
;
Lambais, Marcio Rodrigues
[2]
;
Cerri, Carlos Clemente
[3]
;
Basilio de Azevedo, Lucas Carvalho
[4]
;
Feigl, Brigitte Josefine
Total Authors: 5
|
| Affiliation: | [1] USP, ESALQ, Programa Posgrad Microbiol Agr, BR-13418900 Piracicaba, SP - Brazil
[2] USP, ESALQ, Dept Solos & Nutr Mineral Plantas, BR-13418900 Piracicaba, SP - Brazil
[3] USP, Lab Biogeoquim Ambiental, CENA, BR-13400970 Piracicaba, SP - Brazil
[4] USP, ESALQ, Programa Posgrad Solos & Nutr Mineral Plantas, BR-13418900 Piracicaba, SP - Brazil
Total Affiliations: 4
|
| Document type: | Journal article |
| Source: | Revista Brasileira de Ciência do Solo; v. 33, n. 4, p. 907-916, JUL-AUG 2009. |
| Web of Science Citations: | 26 |
| Abstract | |
It is well-known that Amazon tropical forest soils contain high microbial biodiversity. However, anthropogenic actions of slash and burn, mainly for pasture establishment, induce profound changes in the well-balanced biogeochemical cycles. After a few years the grass yield usually declines, the pasture is abandoned and is transformed into a secondary vegetation called "capoeira" or fallow. The aim of this study was to examine how the clearing of Amazon rainforest for pasture affects: (1) the diversity of the Bacteria domain evaluated by Polymerase Chain Reaction and Denaturing Gradient Gel Electrophoresis (PCR-DGGE), (2) microbial biomass and some soil chemical properties (pH, moisture, P, K, Ca, Mg, Al, H + Al, and BS), and (3) the influence of environmental variables on the genetic structure of bacterial community. In the pasture soil, total carbon (C) was between 30 to 42 % higher than in the fallow, and almost 47 % higher than in the forest soil over a year. The same pattern was observed for N. Microbial biomass in the pasture was about 38 and 26 % higher than at fallow and forest sites, respectively, in the rainy season. DGGE profiling revealed a lower number of bands per area in the dry season, but differences in the structure of bacterial communities among sites were better defined than in the wet season. The bacterial DNA fingerprints in the forest were stronger related to Al content and the Cmic:Ctot and Nmic:Ntot ratios. For pasture and fallow sites, the structure of the Bacteria domain was more associated with pH, sum of bases, moisture, total C and N and the microbial biomass. In general microbial biomass in the soils was influenced by total C and N, which were associated with the Bacteria domain, since the bacterial community is a component and active fraction of the microbial biomass. Results show that the genetic composition of bacterial communities in Amazonian soils changed along the sequence forest-pasture-fallow. (AU) | |