Trace gas fluxes associated with land-cover and land-use changes in the Brazilian Amazon Basin

• Grant number: 97/00446-4
• Support Opportunities: Research Projects - Thematic Grants
• Start date: June 01, 1997
• End date: November 30, 2000
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Carlos Clemente Cerri
• Grantee: Carlos Clemente Cerri
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated scholarship(s): 99/03098-2 - Distribution and biogeochemistry of inorganic compounds associated with the conversion of forest into pasture in Rondônia, using multi-elemental analyses, BP.PD; 98/05557-1 - Appraisal of knowledge relative to the changes in land use in Amazonia and the consequences on the global carbon cycle, BE.PQ; 98/07445-6 - Alteration in the cycle of nitrogen, carbon and phosphorus resulting from changes in land use in the Brazilian Amazon basin, BP.IC; 97/13198-9 - Root system and its influence on the flux of gases in the forest-pasture succession in the Brazilian Amazon, BP.PD

Abstract

We propose to measure changes in key soil processes and the fluxes of Co2, N2O and no associated with the conversion of tropical rainforest to pasture in Rondônia, a state in the southwest Amazon that has experienced rapid deforestation, primarily for cattle ranching, since the late 1970s. in sum, these measurements are intended to provide a comprehensive quantitative picture of the nature of surface soil element stocks, C and nutrient dynamics, and trace gas fluxes between soils and the atmosphere during the entire sequence of land-use change from the initial cutting and burning of native forest, through planting and establishment of pasture grass and ending with very old continuously-pasture land. All of our work is done in cooperation with Brazilian scientists at the Centro de Energia Nuclear na Agricultura (CENA) through an extant official bi-lateral agreement between the marine biological laboratory and the University of São Paulo, CENA s parent institution. in this research we will : 1) make field measurements of P stocks and N2O and no fluxes along two sequences of forest and pastures established between 1989 and 1911 at a large ranch (Fazenda Nova Vida) that we have been studying for the past five years, 2) conduct field studies of C, N and P stocks and C and N cycling rates in soils, and fluxes of Co2, N2O and no between the soil and the atmosphere in a pasture that we created in 1994; 3) develop both response-function and process-based models to predict trace gas flux rates; 4) link these models with geographically-referenced information on rates of forest clearing for pasture to begin to predict how these changes affect trace gas flux rates for the entire Brazilian Amazon basin. (AU)