Italian Nitrogen Network (INN)
Cross comparison of nitrogen sources, sinks and transport within river
basins
Nitrogen deficit or excess within ecosystems imply different problems. The
shortage of this key nutrient strongly affects agricultural productions while its
abundance determines water eutrophication and associated setbacks (“too much of
a good thing”, European Nitrogen Assessment, 2011). At the beginning of 2014, a our group launched a national initiative to researchers dealing with nitrogen, including
limnologists, ecologists, biologists, agronomists and hydrogeologists. The
initiative (INN, Italian Nitrogen Network) consists in sharing a common
methodology to evaluate the nitrogen budget at the watershed level in Italian
rivers.
Specific meetings were organized to share and discuss a common method for data collection and budget calculation. Most necessary data (e.g. arable land, crop production, fertilization practices, livestock and population density) are available from national statistical databases with a resolution of single municipality. All input data are converted into nitrogen units by means of site-specific, appropriate coefficients. An inventory of input (livestock manure, synthetic fertilizers, atmospheric deposition, and biological fixation) and output terms (crop uptake, ammonia volatilization, and denitrification in soils) is produced and a net budget is calculated across the agricultural lands.
As for most Italian rivers water flows and hydrochemical data at the closing sections are available, N export from each basin can be computed and compared to the budget. This, together with detailed knowledge of accessory information (e.g. hydrological regime, irrigation practices, presence of aquatic environments, land use, slopes, soil permeability) allows inferring about the system capacity to metabolize N loads and its relevance in planning appropriate management actions. At present some budgets are already available (Oglio, Mincio, Volano, Agogna, Parma, Secchia, Trebbia, Enza, Crostolo, Adda, Panaro, Adige, Laguna di Venezia), while others are in progress.
The initiative was officially presented in September in Ferrara at the annual congress of the Italian Ecological Society (SiTE).
Specific meetings were organized to share and discuss a common method for data collection and budget calculation. Most necessary data (e.g. arable land, crop production, fertilization practices, livestock and population density) are available from national statistical databases with a resolution of single municipality. All input data are converted into nitrogen units by means of site-specific, appropriate coefficients. An inventory of input (livestock manure, synthetic fertilizers, atmospheric deposition, and biological fixation) and output terms (crop uptake, ammonia volatilization, and denitrification in soils) is produced and a net budget is calculated across the agricultural lands.
As for most Italian rivers water flows and hydrochemical data at the closing sections are available, N export from each basin can be computed and compared to the budget. This, together with detailed knowledge of accessory information (e.g. hydrological regime, irrigation practices, presence of aquatic environments, land use, slopes, soil permeability) allows inferring about the system capacity to metabolize N loads and its relevance in planning appropriate management actions. At present some budgets are already available (Oglio, Mincio, Volano, Agogna, Parma, Secchia, Trebbia, Enza, Crostolo, Adda, Panaro, Adige, Laguna di Venezia), while others are in progress.
The initiative was officially presented in September in Ferrara at the annual congress of the Italian Ecological Society (SiTE).