Contact/s:
Lorena Giglio (CRPA)
l.giglio@crpa.it
Soil Health and Nitrogen Efficiency: Precision Top-Dressed Slurry Application Cuts Synthetic Fertilizer Use and Ammonia Losses
Europe
All
1. Organic matter
2. Nutrient cycling
3. Effluent disposal
Thematic Areas
Production System/s
Summary for Practicioners on the Main Finding(s)/Innovative solution(s)
The intensification of crop and livestock production has increased the volume of livestock manure requiring management. Areas suited to livestock farming may face nutrient surpluses, while crop-producing areas can have a growing demand for mineral fertilisers.
Within Climate Farm Demo, carbon audits and Adaptation and Mitigation Plans (AMPs) help identify nutrient-management challenges and suitable climate-smart measures at farm level. CRPA technical guidance can support the interpretation and implementation of measures related to the management and redistribution of livestock effluents and digestate.
The distribution of nutrients from livestock effluent and digestate can present operational challenges linked to soil and climatic conditions. Top-dress application allows nutrients to be used by growing crops, potentially replacing part of the mineral fertiliser requirement and enabling application at appropriate times and doses using suitable machinery.
Top-dressing can increase the efficiency of nitrogen use by crops and extend the period during which effluents can be applied. It may also support the redistribution of nutrients to areas poorer in organic matter.
Existing application techniques perform differently depending on the context. Before implementation, farmers and advisors should assess soil conditions, crop type, machinery and effluent characteristics. Some systems, such as Pivot or Ranger, may require suitable effluent pre-treatment, while other techniques, such as trailing shoes, may affect crop performance under specific soil and crop conditions.
In terms of implementation, these measures should be considered as options rather than universally applicable solutions. Their suitability depends on the farm system, soil and climatic conditions, available resources and the farmer’s objectives. Carbon-audit results and AMPs can help farmers and advisors assess whether these techniques are appropriate for a specific farm.
Summary for Practicioners in Native Language
L’intensificazione delle produzioni agricole e zootecniche ha portato all’aumento dei quantitativi di effluenti zootecnici da trattare. In particolare, nelle zone vocate alla zootecnia si osserva un elevato surplus di nutrienti, mentre nelle aree vocate alle produzioni vegetali si registra una crescente richiesta di concimi chimici.
La distribuzione dei nutrienti presenti negli effluenti e nei digestati zootecnici può presentare difficoltà operative legate alle condizioni pedoclimatiche del territorio. L’impiego in copertura permette di valorizzare i surplus nutritivi territoriali sostituendo i fertilizzanti minerali e permette di distribuire, tramite mezzi agricoli idonei, il nutrimento nel momento e nelle dosi corrette a seconda della coltura di riferimento.
L’applicazione in copertura permette all’azienda agricola di distribuire su colture in atto, incrementando l’efficienza di utilizzo dell’azoto da parte della vegetazione con una maggiore resa produttiva e un minor impatto ambientale. Inoltre, in questo modo si amplia la finestra temporale di spandimento degli effluenti, grazie alla possibilità di distribuire anche quando le condizioni pedoclimatiche non sono ottimali. Infine, permette di delocalizzare i nutrimenti in aree più povere di sostanza organica.
Le tecniche distributive esistenti hanno prestazioni differenti a seconda del contesto ed è importante valutare alcuni aspetti prima di applicarle a livello aziendale. In alcuni casi, ad esempio, è necessario adottare opportuni sistemi di pretrattamento degli effluenti (Pivot o Ranger), mentre altre tecniche, in alcune condizioni di terreno e su determinate colture, potrebbero influire sulle rese (trailing shoes).
In termini applicativi, si raccomanda di considerare le misure proposte nel progetto come spunti e non soluzioni universalmente valide, poiché la reale idoneità dipende dal sistema aziendale, dalle condizioni climatiche, dalle risorse e dagli obiettivi dell’agricoltore.
Additional Information
There are various types of agricultural machines used for the surface application of manure.
For example, with Pivot or Ranger, it is possible to apply microfiltered digestate as a fertilizer, which is mixed with water and applied via fertigation. This system requires a series of operational steps prior to field application, such as the solid-liquid separation of the slurry, resulting in the production of a clarified fraction intended for the subsequent microfiltration stage.
The optimal agronomic use of the microfiltered fraction is therefore its application to growing crops, to maximise nutrient use efficiency and reduce the need for synthetic fertilisers.
There are also band-spreading and trailing-shoe systems, comprising low-pressure distribution bars that allow the effluent to be applied in surface bands directly onto the soil (band spreading) or in bands with slight incorporation by trailing shoes. This localised application reduces both the soiling of vegetation and ammonia emissions into the atmosphere, as the area affected by the spreading is limited. These bar distribution systems can be fitted directly to tractors and supplied via a hose, mounted at the rear of tank trailers, or installed on self-propelled tankers.
The system known as the ‘mole’ is a self-propelled injector fitted with a tank for distributing livestock effluent and digestate during periods of maximum nutrient uptake by the plants; it is capable of operating in the field even when the crop has grown to over one and a half metres in height without damaging it and is therefore ideal for distributing effluent by burial between the rows of crops such as maize and sorghum.
Choosing the most suitable method is crucial to achieving positive results within the enterprise, and the role of an adviser is precisely to build the best strategy for the enterprise.