Root system and its incluence on the flux of gases in forest / pasture succession in Brazilian Amazonia

• Grant number: 98/09642-3
• Support Opportunities: Regular Research Grants
• Start date: January 01, 1999
• End date: December 31, 2000
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Brigitte Josefine Feigl
• Grantee: Brigitte Josefine Feigl
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The introduction of pastures into Brazilian Amazonia, after the felling of the native forest, has provoked alterations in the cycling of carbon (C) and in the flux of carbon dioxide (CO2) into the atmosphere. It is known that the quantity of CO2 evolved from the soil is derived principally from the organic matter in the soil (SOM) and from the respiration of the roots. Considering that, for this region, little or nothing is known about the distribution of roots and their interactionwith the attributes of the soil (soil-root interfaces),the present study has the main objectives of ascertaining the existing relationships between the root system of pastures and of native forest and some attributes of the soil, such as the density and porosity, the stock of C and consequently the flux of CO2 into the atmosphere. Admitting that, for these studies, the methodology for the evaluation of the roots is identified as the main limiting factor and that an adequate evaluation of the root system may require the application of different methodologies, producing discrepant results with significant variability, in this work we will use the methods of monolith, needle board and the method assisted by the processing of digital images. Thus,we have additional specific objectives of ascertaining the existing correlations between the respective results for the different methods and to analyze the effects of spatial and temporal variability associated with these results. As fundamental complement, this study also intends to use the technique of computerized tomography for the evaluation of the roots and of the soil-root interface. (AU)