Last November (2022), the National Council of Scientific Research (CSIC)), one of the Spanish partners of CEOMED,  uploaded one scientific article to the Journal of Soil Science and Plant Nutrition that it is already available on the Springer Link website. The article is named: "Carbon and Nitrogen Mineralisation in Soils and Nutrient Efficiency of Digestates from Fruit and Vegetable Wastes". 

The scientific paper describes the experiments done to define the agronomic value of digestate from fruit and vegetable wastes using anaerobic digestion. They did the experiment on 2 types of crops: maize and cardoon.
Using this type of digestion allows appropriate management and helps to complete the cycle of the circular economy as it converts waste into resources: biogas, a renewable source of energy, and digestate, rich in nutrients of interest for agriculture. 
One of the most interesting results that has been demonstrated is that the quality of the digestates produced from fruit and vegetable residues was adequate for agricultural soil application, according to their concentrations of nutrients and their nutrient recovery efficiencies for the potential substitution of mineral fertilisers. 
However, the Na+ concentrations of the digestates could limit their use in soil, since prolonged digestate application may cause salt accumulation in soil, and so their use in salt-sensitive crops should be restricted.
 

You can read the full article here