Amazon forest Soil metagenome (nifH gene amplicon sequencing)

This project investigated the diazotrophic community (nitrogen fixing microorganisms) response to change in the land use of tropical forests and recovery in the secondary forests. We have applied a nested sampling approach that covered from few cm to 10 km distance of each of the three land use systems (primary forest, pasture, and secondary forests) and sequenced nifH genes using high-throughput sequencing. Soil samples were collected from the state of Rondônia, Brazil, in 2010. This site was selected because it went under extensive deforestation from 1996 to 2005. Primary forest was cleared by removing large trees for timber and burning the remaining vegetation to create pasture lands that have been vegetated with two fast growing grasses (Urochloa brizantha and Panicum maximum). Once pastures became unproductive, they are abandoned, allowing secondary vegetation to grow. These secondary forests have much lower plant diversity as compared to the primary forests.