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Description:  The ND–03 Deegan/Victoria team is measuring soil processes and stream chemistry in two pairs of drainage basins in Rondônia. The study area is southeast of the town of Ariquemes (6.1.3.1) in an area called Fazenda Nova Vida, which is 220 km2 in area and the site of ongoing MBL–CENA cooperative research on soil biochemistry and trace gas fluxes. The paired basins are approximately 10 km2 and are on the Nova Vida property. The rivers formed by the confluence of the paired basins, Rio Quatro Cachoeiras and Rio Andirá, also serve as sampling sites. One drainage basin in each pair has had land use exclusively of native forest; the other exclusively cattle pasture. These basins contain permanently flowing second–order streams closely matched in area and discharge. Second–order forest streams in the region are typically one to four meters wide, with clear water and sandy bottoms, and have a pH of 5.5 to 6.8. The forested basins contain moist terra upland forest, and pastures surround two of the drainage basins that were created in 1989. Forest vegetation consists of open perennially evergreen broadleaf trees with a high number of palms (Pires and Prance, 1986), and pastures have been planted with the widely used grass Brachiaria brizantha. All of the basins occupy a gently rolling topography with soils that are typical of large areas of the western Amazon Basin. Soils are well drained Kandiudults and Paleudults (red–yellow podzolic Latosols in the Brazilian classification). Clay content in these Ultisols generally ranges from 10 to 40% (Moraes et al., 1996). Mean annual temperature is about 27° C and varies by less than 4° C between warmest and coldest months (Bastos and Diniz, 1982). The elevation is 200–500 m in the region, which is generally underlain by Pre–Cambrian granitic rock (Projeto Radambrasil, 1978). Central Rondônia gets 2.2 m of rainfall annually and has a 5–month dry season.

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