The significant rate of deforestation in the Amazon region has become a global concern. This process consists substantially in the conversion from forest to agricultural systems, which is the activity that drives the local economy. This new ecosystem formed requires studies that elucidate its operation, seeking to understand how this region interacts with the atmosphere. To investigate the behavior of energy balance components in a grassland ecosystem, a study was conducted at Fazenda Nossa Senhora (FNS), in Ouro Preto do Oeste, Rondônia. This study examined net radiation and sensible, latent and soil heat fluxes patterns, in the periods: wet, wet-dry, dry and dry-wet from 2000 to 2005. Measurements of sensible and latent heat fluxes were performed using the eddy covariance method. The results of these analyses showed that the partitioning of energy in the grassland were 77.8, 69.6, 50.6 and 75.2%, respectively in the wet, wet-dry, dry and dry-wet periods, for the latent heat flux and 22.5, 31.2, 46.7 and 24.7% for the sensible heat flux, indicating a higher vulnerability of grassland to seasonal changes.
grassland; energy fluxes; eddy correlation
