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Gewählte Master / Diploma Thesis:

Philipp Simon Ledesma (2021): Measuring Soil Gas Fluxes: Evaluation of a portable chamber approach to quantify carbon storage in ecological restoration projects, New Zealand.
Master / Diploma Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 69. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Soils play a critical role in global climate change as they can either act as source or sink of atmospheric greenhouse gases (GHGs). Adapted land management sequestering soil organic carbon (SOC) is an effective tool to mitigate net GHG emissions while strengthening food security by improving soil fertility. Thus, there is growing international interest in reliable monitoring of SOC stocks and stock changes. In-situ measurements of soil gas fluxes can deliver valuable information about C and N dynamics on a small scale, and improve GHG inventories and SOC models. Even though the accuracy of measurement devices improved significantly, specific expertise and appropriate planning are needed to derive meaningful outcomes. The present thesis aims to evaluate the usability of a portable chamber system for soil gas flux measurements on a farm scale. It assesses how the approach could be implemented into broader restoration projects. Therefore, a case study was conducted in an intensively used agricultural area within the Canterbury region, New Zealand, looking at the influence of vegetation complexity and the implementation of trees on soil gas fluxes. Primary outcomes revealed that vegetation composition significantly influenced CO2 release and that it was lowest under native vegetation dominated by kānuka trees. Furthermore, soil moisture was the most influential controlling factor under prevalent dry conditions, limiting CO2 effluxes even under high temperatures. N2O effluxes were generally at a low level. Due to methodological difficulties of N2O measurements under the low natural levels of microbial N2O production, its use in future projects was finally not recommended. Measurements of CO2 delivered a meaningful set of data with values comparable to the literature and could thus be effectively implemented in further studies. However, prospective users should pay special attention to a sophisticated experimental design accounting for spatial and temporal variations.

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