Soil Denitrification, the Missing Piece in the Puzzle of Nitrogen Budget in Lowland Agricultural Basins

Abstract Denitrification is a key process buffering the environmental impacts of agricultural nitrate loads but, at present, remains least understood and poorly quantified sink in nitrogen budgets watershed scale. The present work deals with comprehensive detailed analysis sources sinks Burana–Volano–Navigabile basin, southernmost portion Po River valley (Northern Italy), an intensively cultivated (> 85% basin surface) low-lying landscape. Agricultural census data, extensive monitoring surface–groundwater interactions, laboratory experiments targeting N fluxes pools were combined to provide reliable estimates soil denitrification In soils inputs exceeded outputs by nearly 40% (~ 80 kg ha −1 year ), but this condition potential excess did not translate into widespread pollution. general scarcity inorganic species groundwater indicated limited leakage storage. Multiple pieces evidence supported that was needed be introduced budget explain fate missing nitrogen. likely boosted studied prone waterlogged conditions consequently oxygen-limited, owing peculiar features such as fine texture, low hydraulic conductivity, shallow water table. study highlighted substantial contribution balancing lowland basins, paramount ecosystem function preventing eutrophication phenomena.