M. Zilio, A. Pigoli, B. Rizzi, F. Tambone, F. Adani

M. Zilio*, A. Pigoli, B. Rizzi, F. Tambone, F. Adani

Ricicla Group - Department of Agricultural and Agronomical Sciences - Production, Landscape,

Agroenergy, Università degli Studi di Milano, Milan, Italy

The production and use of mineral fertilizers represent a growing problem on a global scale. Compared to 1960, the amount of mineral nitrogen fertilizers consumed globally every year has increased by 840% 1 . A valid alternative is represented by renewable fertilizers, which allow to recover nutrients from biowaste, avoiding the need to produce mineral fertilizers 2 .

On the other hand, misuses of biowaste or derivatives as fertilizers can lead to pollution problems, such as the release of ammonia into the atmosphere 3 . Ammonia is responsible for water eutrophication, acid deposition, but above all for secondary particulate formation 4 . The presence of particulates has been recently reported to be a direct cause of lung cancer and chronic diseases of the respiratory system 5 . In addition, another issue not to be underestimated are odorous emissions, which can cause disturbance in nearby areas, and drive people to refuse the use of renewable fertilizers 6 .

In this work, which is part of the EU H2020 SYSTEMIC project, we used digestate obtained as by-product from biogas production as fertilizer in a three-year open-field experiment. The ammonia and odour emissions after injection of digestate into the soil were monitored and compared with those derived from the use of urea.

The results showed that ammonia and odour emissions measured with the use of digestate and urea are very similar. However, the environmental conditions at the time of spreading could have a different impact on the amount of ammonia emitted by the two fertilizers.

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