Evaluation of N 2 O and NH 3 emissions from the use of digestate as fertilizer on silage maize

Transcription

1 20th N workshop - Rennes, 26 June 2018 Evaluation of N 2 O and NH 3 emissions from the use of digestate as fertilizer on silage maize Verdi L. 1, Kuikman P.J. 2, Orlandini S. 1, Mancini M. 1, Napoli M. 1, Dalla Marta A. 1 1 Department of Agrifood Production and Environmental Sciences (DISPAA), University of Florence, Piazzale delle Cascine Firenze, Italy 2 Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands Intervento realizzato con il cofinanziamento FEASR del Programma di Sviluppo Rurale della Regione Toscana sottomisura 16.2 progetto GrANT

2 Introduction Emissions from Italian agricultural sector accounts for: 11% of CO 2 50% of CH 4 (GWP = 28-36) 68% of total N 2 O (GWP = ) 94% of NH 3 Main sources are represented by fertilization, intense livestock systems and fuels Nowadays, low-impact agricultural management strategies are a hot topic Digestate is by-product of biogas production process and represents an alternative to mineral fertilizers due to the high N-easily available for crops (NH 4+ )

3 Aim Evaluation of different fertilization strategies and their role on the reduction of environmental impacts from agriculture Nitrous oxide and Ammonia emissions from fertilization Yields, N Mass Balance and NUE

4 Materials and Methods 4 replicates 3 treatments: Control (no fertilization) Liquid fraction of digestate MineralFertilizer (Urea) 12 tanks (volume 1 m -3 ) Fertilization rate 150 Kg N ha -1 crop: SilageMaize (var. Ronaldinio) Unit Liquid fraction of digestate N (Kj) g Kg NH + 4 g Kg NO 3 - g Kg P g Kg K g Kg

5 Materials and Methods Parkin and Venterea, 2010

6 OECD and EUROSTAT, Gross Nitrogen Balance, HANDBOOK Giardini L., Agronomia Generale Ambientale e Aziendale Materials and methods N surplus = N fertilizer + N deposition N harvest NUE = (N output (uptake) fertilized plot N output (uptake) control plot ) / N input fertilized plot Nitrogen inputs: A Fertilizers N deposition Others (seeds, planting matherials and crop residues) FARM UNIT Nitrogen outputs: B A B NITROGEN SURPLUS Emissions (volatilization, denitrification) Leaching Marketed crops Fodder crops and grass

7 Results First fertilization kg N 11days -1 ha -1 Second fertilization kg N 11days -1 ha -1 Cumulative losses kg N 25days -1 ha -1 Treatment N 2 O-N NH 3 -N N 2 O-N NH 3 -N N 2 O-N NH 3 -N N Digestate Urea Control Digestate NH 3 emissions reduced by 66,32% Cumulative N emissionlosses reduced by 23,73% Urea N 2 O emissions reduced by 22,63%

8 Results t DM/ha N kg ha -1 Digestate Urea Control digestate urea control Yield t DM ha -1 Digestate Urea Control 9.12 N kg/ha digestate urea control

9 Nitrogen Surplus // NUE Unit Control Digestate Urea N fert Kg ha N dep Kg ha N harv Kg ha N surplus/deficit Kg ha NUE

10 Conclusions Digestate allows the reduction of N cumulative emission losses Crop uptake represents the most relevant N output factor Digestate represent an alternative to urea to reduce environmental impact of agriculture and ensure sustainable yields N Mass Balance is a useful tool for the evaluation of environmental impact of agricultural management strategies Specific consideration are needed regarding sustainability of the process of each fertilizers

11 Thanks for your attention Leonardo Verdi PhD Skype: leonardo.verdi88