Misura e simulazione dei flussi di C in sistemi colturali erbacei nella provincia di Viterbo
Author(s)
Ponziani, Stefano
Date Issued
July 7, 2015
Type
Doctoral Thesis
Abstract
The international scientific community agrees that climate changes are caused by human activities. It is estimated that annually agriculture affects atmospheric emissions of greenhouse gases directly and indirectly, to a share between 9 ~ 12 Pg CO2 eq yr-1, approximately 24% of global emissions. In the agricultural sector the variability and uncertainty of how the biogeochemical cycles of the soil affect the fluxes of such emissions, are not well known and are currently under investigation, since GHG emissions are strongly influenced by the type of crop, climatic conditions and the local agricultural practices.
In the agricultural sector of the province of Viterbo, that covers an area of approximately 2.810 km2, characterized by a Mediterranean climate with dry summer, there have been a few studies taking into account the fluxes of carbon that are determined during the cultivation of field crops. In this context, in order to quantify and to contrast the fluxes responsible for climate change, the research carried out in these years of study, has measured and monitored carbon fluxes (Net Ecosystem Exchange) at the experimental site with the eddy covariance technique, defining the carbon balance, (NECB) for the agricultural years from 2009 until 2013.
At the regional level, the fluxes of NEE were estimated during the cultivation of durum wheat (Durum wheat Desf.) and crimson clover (Trifolium incarnatum L.), two characteristic crops of agricultural landscape of Viterbo. To determine the spatial fluxes of NEE, images from LANDSAT 2009 satellite and the DNDC 9.5 simulation model have been used. The information used as agricultural inputs in the model to simulate at the regional level was extracted from the database of crop management, assembled during this PhD research. This database contains information about agronomic practices characteristic for the Province of Viterbo, applied during the crops cultivation.
The results obtained at the site allowed us to understand how the fodder crop and grassland are sink of carbon, with a range that varies from -25.65 g C m-2 equivalent to -464.78 g C m-2 equivalent, because they can store more carbon in the agro ecosystem than they lose, while durum wheat has revealed a carbon source but with very low values 16.05 g C m-2 equivalent.
At the regional simulation the spatial distribution of the fluxes of NEE has allowed to understand how farming practices, associated with the management of the examined field crops, may affect these fluxes, partly by reducing the uncertainties due to the variables that become part in biogeochemical cycles of the soil, improving the understanding of the dynamics of the fluxes of greenhouse gases in the agricultural sector of the Province of Viterbo.
This research with further in-depth analysis could be a starting point for possible implementations of reduction strategies and mitigation in agriculture landscape in Central Italy.
Additional information
Dottorato di ricerca in Ortoflorofrutticoltura
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