Soils in Malta are alkaline and has a low content of organic matter (OM), not least because there over decades has been established a practice of dumping livestock manures to the nature and sea, partly via overburdened wastewater treatment plants, rather than exploiting it as valuable crop fertiliser and recycle the nurients in a legal way. The situation causes increased need for irrigation due to the low water binding capacity of the soils and higher and higher mineral fertiliser use since nutrients generally have lower availability outside optimal pH values. The declining soil health is like a vicious circle. The SYNECO project, which ended in September 2025, has piloted a value chain for responsible management of livestock slurries by processing this into digestates that are further used for production of bio-based fertilisers, in specific Ammonia Sulphate Solution (ASS) and Separation Solids that are planned to be made into manure granules later on. Besides that, there is also a Reject Water fraction.
Organe Institute has as part of the project produced a technical report that analyses some immediately expected agronomic and environmental impacts of the mentioned end and by-products.
The report concludes that the three end- and by-products of SYNECO's manure processing - Ammonia Sulphate Solution, Separation Solids of Digestates and Reject water - overall offers not only effective fertilisation, but in addition a soil healing effect. They have potential to reduce the high pH of Maltese soils and increase the low organic matter content. Recycling of the Reject Water would also make Maltese crop production less dependent on Maltas scarce irrigation water resources. The three bio-based fertilisers would however not as the only fertiliser types offer a well-balanced fertilisation in all situations, but in some cases give an undersupply of potassium and risks for oversupply with phosphorus and sulphur. Therefore, it would still be necessary to use other fertilisers to balance crop nutrient demand.
Download the technical report from here.