Effect of mitigation techniques on ammonia emissions and nutrients recovery: The role of fertigation with digestate

Digestate is an important source of nutrients for crops but if not properly managed its use can cause environmental problems, mainly caused by nitrogen losses. Appropriate techniques are required for its field application in order to reduce nitrogen losses and increase the nitrogen use efficiency (NUE). Under the ARIMEDA project (LIFE16 ENV/ES/000400), two different fertigation techniques (drip and pivot irrigation systems) were assessed on maize by using the digestate liquid fraction. A two-year field test was carried out in Lombardy, testing fertigation with pivot or drip systems compared to reference fields irrigated using the same systems and fertilized with digestate applied at base dressing with broadcast spreader. Both pivot and drip irrigation systems were suitable for fertigation of maize with digestate. The obtained results reveal the feasibility and the positive effect on nitrogen use efficiency and nitrogen emissions of this technique, if digestate is properly managed, adequately filtered according to the fertigation technique and combined with appropriate spreading technique in pre-sowing fertilisation.