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Wasser- und Elementflüsse als Indikatoren für nachhaltige Landnutzungssysteme - Fallstudie Cerrado, Brasilien

DFG (ZE 154/36-3)

Von 01/2002 bis 12/2000

Projektleiter: Bernd Huwe

Water and nutrient fluxes as indicators for sustainable land use in the Cerrado region of Brazil (funded by German Research Foundation (DFG) - Ze 154/36-1, -2) Responsible:Julia Lilienfein, Wolfgang Wilcke Period: February 1997 - January 2000 Partners: Centro Internacional de la Agricultura Tropical (CIAT), Cali, Colombia Empresa Brasileira da Pesquisa Agropecuária (EMBRAPA) - Cerrados, Plantaltina-DF, Brazil Universidade Federal de Uberlândia, Uberlândia, Brazil For about 15 years, the Brazilian savannas, the so-called Cerrados are intensively logged and agriculturally used. The currently most important land-use systems are pastures (differing considerably in quality), Pinus plantations, and corn-soybean rotations under conventional tillage and no-till. Land-use practices include strong mechanization and a high input of agrochemicals. Thus, there is a considerable risk of damaging the sensitive savanna ecosystem and of a rapid loss of soil fertility at the agriculturally used sites. To improve the sustainability of the land use, knowledge on its impact on nutrient and water fluxes is necessary. In an international project we are studying the water- and nutrient fluxes in six land-use systems: native savanna, Pinus forestation, conventional and no-till cropping systems, degraded and productive pasture. Master theses (Diplomarbeiten) Dynamics of dissolved organic C and N (DOC and DON) in the soil solution of differently used savanna soils. Dissolved organic substances contribute to plant nutrition with N. Due to their water solubility there is a considerable risk for leaching of these species resulting in enhanced soil degradation. The dynamics of dissolved organic substances is influenced by the quantity and the quality of soil organic mater, the sorption characteristics of the soils and the microbial activity. All these parameters are modified by land use. In this work DOC and DON concentrations in the soil solution during one rainy season will be studied. Nutrient deposition into differently used systems. The ratio of input to output of a system determines if nutrients are accumulated or depleted. In this work, the above canopy deposition, the throughfall, the stemflow, the litter fall and inputs by fertilization will by quantified and compared for the different systems. Water and nutrient status of natural Cerrado and Pinus plantations. First results show that that soils under Pinus vegetation dry more rapidly and are more acid than under natural Cerrado. We assume that there is a considerable nutrient uptake by roots from the subsoil due to more favorable conditions for root growth. Within this work, precipitation, interception, transpiration, and root distribution in soil will be studied to test these hypotheses. The work can be started between January and March 1999. It requires a 2-3 months stay in Brazil to collect the samples and 4-6 months laboratory work. Applications of students of soil science, geoecology, biology, forestry, agriculture or related sciences with basic chemical laboratory experience are welcome. Water and nutrient fluxes as indicators for sustainable land use in the Cerrado region of Brazil (funded by German Research Foundation (DFG) - Ze 154/36-1, -2) Responsible:Julia Lilienfein, Wolfgang Wilcke Period: February 1997 - January 2000 Partners: Centro Internacional de la Agricultura Tropical (CIAT), Cali, Colombia Empresa Brasileira da Pesquisa Agropecuária (EMBRAPA) - Cerrados, Plantaltina-DF, Brazil Universidade Federal de Uberlândia, Uberlândia, Brazil For about 15 years, the Brazilian savannas, the so-called Cerrados are intensively logged and agriculturally used. The currently most important land-use systems are pastures (differing considerably in quality), Pinus plantations, and corn-soybean rotations under conventional tillage and no-till. Land-use practices include strong mechanization and a high input of agrochemicals. Thus, there is a considerable risk of damaging the sensitive savanna ecosystem and of a rapid loss of soil fertility at the agriculturally used sites. To improve the sustainability of the land use, knowledge on its impact on nutrient and water fluxes is necessary. In an international project we are studying the water- and nutrient fluxes in six land-use systems: native savanna, Pinus forestation, conventional and no-till cropping systems, degraded and productive pasture. Master theses (Diplomarbeiten) Dynamics of dissolved organic C and N (DOC and DON) in the soil solution of differently used savanna soils. Dissolved organic substances contribute to plant nutrition with N. Due to their water solubility there is a considerable risk for leaching of these species resulting in enhanced soil degradation. The dynamics of dissolved organic substances is influenced by the quantity and the quality of soil organic mater, the sorption characteristics of the soils and the microbial activity. All these parameters are modified by land use. In this work DOC and DON concentrations in the soil solution during one rainy season will be studied. Nutrient deposition into differently used systems. The ratio of input to output of a system determines if nutrients are accumulated or depleted. In this work, the above canopy deposition, the throughfall, the stemflow, the litter fall and inputs by fertilization will by quantified and compared for the different systems. Water and nutrient status of natural Cerrado and Pinus plantations. First results show that that soils under Pinus vegetation dry more rapidly and are more acid than under natural Cerrado. We assume that there is a considerable nutrient uptake by roots from the subsoil due to more favorable conditions for root growth. Within this work, precipitation, interception, transpiration, and root distribution in soil will be studied to test these hypotheses. The work can be started between January and March 1999. It requires a 2-3 months stay in Brazil to collect the samples and 4-6 months laboratory work. Applications of students of soil science, geoecology, biology, forestry, agriculture or related sciences with basic chemical laboratory experience are welcome.

Letzte Änderung 30.11.2005