agronomy Article Fertigation of Maize with Digestate Using Drip Irrigation and Pivot Systems Viviana Guido 1,*, Alberto Finzi 1 , Omar Ferrari 1, Elisabetta Riva 1, Dolores Quílez 2 , Eva Herrero 2 and Giorgio Provolo 1 1 Department of Agricultural and Environmental Sciences, University of Milan, Via Celoria 2, 20133 Milano, Italy; alberto.fi
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[email protected] (G.P.) 2 Department of Soil and Irrigation, Agrifood Research and Technology Centre of Aragon (CITA), Avda. Montañana 930, 50059 Zaragoza, Spain;
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[email protected] Received: 22 August 2020; Accepted: 21 September 2020; Published: 23 September 2020 Abstract: Digestate is a nutrient-rich fertilizer and appropriate techniques are required for its application during the maize season to reduce losses and increase the nitrogen use efficiency (NUE). The performance of two different fertigation techniques (drip irrigation and pivot) were assessed using the digestate liquid fraction. A two-year field test was carried out at two different sites in Lombardy, northern Italy. At each site, fertigation with pivot (P-F, site 1) or drip (D-F, site 2) systems was compared to reference fields where the same irrigation techniques without addition of digestate were used. During the two seasons, the performance of the fertigation systems, amount of fertilizers used, soil nitrogen content, yields, and nitrogen content of the harvested plants were monitored. The digestate application averaged 5 m3/ha per fertigation event with P-F and 4.9 m3/ha with D-F corresponding, respectively, to 28 and 23 kg N/ha.