SHUTTLE - nutrientS Hotmoments dUe To exTreme hydroLogic Events

Abstract:

Risultati attesi: 

The application of nitrogen (N) and phosphorus (P) fertilizers has substantially increased global food production but has unintentionally impacted the chemical and biological quality of inland and coastal waters. Despite the implementation of several European and national regulations, dramatic contamination is reported for European waters, with hotspots in Denmark, Belgium, the Netherlands, and northern Italy. Such contamination results in human and animal health problems, loss of recreational attractiveness, biodiversity, and ecosystem services, and increases depuration costs. This issue is increasingly complex in the context of climate change, which affects the timing and intensity of nutrient export, due to extreme rainfall events or prolonged drought, affecting water management and irrigation strategies.
The SHUTTLE project (nutrientS Hot moments dUe To exTreme hydroLogic Events) explored the drivers and dynamics governing N and P displacement from arable land to surface and groundwater along the land-aquatic continuum. The research was conducted in two intensively cultivated, farmed, and irrigated watersheds, the Chiese and Volano rivers, located in the Po River Basin, both affected by hydroclimatic extremes but differing in livestock density, fertilizers practices, soil permeability and pollution vulnerability.
SHUTTLE characterized and classified the two basins through the calculation of the N and P soil budgets at both watershed and municipal scales, based on detailed inventories of nutrient inputs and outputs across the agricultural land. Erosion risk was also assessed to support identification of zones with heightened vulnerability to diffuse pollution. These analyses allowed for the spatial identification of hotspots where the water contamination risk is higher. Monthly monitoring of N and P riverine loads was conducted at multiple stations to evaluate how much of the soil nutrient surplus is effectively displaced to the hydrosphere. These samplings were coupled with high-frequency, intensive samplings carried out during hydrological extremes via the use of automatic samplers, to reveal and quantify the contribution of hotmoments in N and P mobility. Mesoscale experiments on irrigated fields and secondary drainage canals, together with laboratory incubations, provided insights into N and P mobilization, soil accumulation and removal processes under both field and controlled conditions.The collected data enables a comprehensive assessment of the mechanisms controlling nutrient fluxes across the soil-water continuum under variable climatic conditions. The outcomes contribute to a scientific basis for delineating future guidelines for sustainable nutrient and water management in agricultural landscapes.