Modelling soil erosion and related organic carbon transport
According to present knowledge the study area is subjected to severe soil erosion causing substantial economic and environmental problems. Taking account of ongoing deforestation and regional climate change it is to be expected that future erosion rates may increase significantly. Continuous erosion leads to a massive loss of topsoils including the loss of organic carbon, which causes a progressive decrease of natural soil fertility. Consequently the ability of soils to accumulate organic carbon is reduced proportionately to the drop in soil productivity. Transported sediments and organic carbon will partly be accumulated in or enter surface water bodies and might be deposited in the riparian zones of the drainage system. All in all we can conclude that erosion induced losses of organic carbon will not pass over into atmosphere for the most part. But soil erosion limits substantially the potential of soils to sequester atmospheric CO2 by generating humus.
In order to control soil degradation and organic carbon losses in the Southern Amazonia region effectively a Decision-Support-System (DSS) should be developed and implemented. As an integral component of the DSS this part of the project aims to adopt and validate an advanced soil erosion and deposition model EROSION 3D for the southern Amazonia region. Using the model it will be possible to:
(1) identify the hotspots of soil loss or deposition on plot and regional scale under present and future climate and socio-economic conditions
(2) estimate the related nutrient and organic carbon losses/yields
(3) locate the pass over points at which eroded sediments, particle-bound nutrients and particulate organic matter enter surface water bodies
The study will put emphasis on further evaluation of optional tillage practices in terms of soil erosion control. Another focus will be put on the assessment of passive control measures like buffer strips, grassed and forested waterways etc.
Prof. Dr. J. Schmidt
Technical University Freiberg (Soil and water conservation unit)
Dr. Marcus Schindewolf