Impact of Eucalyptus plantations on pasture land on soil properties and carbon sequestration in Brazil
Soil organic carbon (SOC) stocks and fluxes in forest ecosystems are influenced by natural and human disturbances. In the tropical regions the highest impacts on disturbance in forest C cycles are related to human activities such as conversion of natural lands to cropland and pasture areas and to fo...
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| Formato: | Second cycle, A1E |
| Lenguaje: | sueco Inglés |
| Publicado: |
2014
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| Acceso en línea: | https://stud.epsilon.slu.se/6394/ |
| Sumario: | Soil organic carbon (SOC) stocks and fluxes in forest ecosystems are influenced by natural and human disturbances. In the tropical regions the highest impacts on disturbance in forest C cycles are related to human activities such as conversion of natural lands to cropland and pasture areas and to forest plantations. The disturbances in the forest C cycles will release CO2 emissions to the atmosphere triggering global warming. In this study the focus was set in subtropical soils in Brazil, south extreme region of Bahia. The aim of the study was to investigate whether reforestation of Eucalyptus plantations under former pasture areas will help mitigate climate change through carbon sequestration. Field measurements were made on the total SOC and nitrogen amount, along with soil physical and chemical attributes, between different land use systems , also to analyze if there will be any positive effect on soil chemical and physical properties with the reforestation. The study areas included the intact rainforest Mata Atlântica called Native Forest, as a reference, pasture areas, which have been settled in the past from deforestation of Mata Atlântica, and Eucalyptus plantations recently reforested under former pasture areas aimed for paper and pulp production. With the field measurements and simulated amounts of SOC using the CO-Fix V.3.2 programme it could be compared the effects on SOC sequestration in short and long term ( max. 50 years) under the Eucalyptus reforestation. Our results show significant differences with lower SOC, higher pH and soil compaction under pasture areas after deforestation of the rain forest. Meanwhile reforestation with eucalypt plantations on former pasture areas did not lead to any significant total nitrogen and total SOC accumulations in short term. However, the simulated results showed that Eucalyptus reforestation will play a role on carbon sequestration in soils with time. After 20 years of production the Eucalyptus forests will gain higher SOC accumulations than in pasture systems. After 50 years the simulated SOC accumulation showed closer values to the amounts measured on field under the Native Forest areas. These results indicate that the Eucalyptus plantations are efficient at sequester carbon in the soil in the long term. However, the comparison with the Native Forest field measurements should be carefully interpret since the measurements on field were made within a certain depth while the program shows the total amount with no limited soil depth. For a complete comparison it remains to take deeper soil samples in the field measurements. |
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