Agronomic and environmental assessment of a new fertilization strategy using pelleted organo-mineral fertilizers for wheat production in mediterranean agricultural soils

The use of compost in extensive cropping systems is not economically viable due to the high application rates required to meet nutrient requirements. However, compost pelleting increases nutrient concentration while reducing storage, distribution, and application costs. This study evaluated the effects of compost pellets fertilization compared to conventional management on agronomic efficiency and environmental impact in wheat production. Eleven treatments were applied in triplicate to 24 m² plots during the 2022-2023 wheat cycle, combining high phosphorus pellets at sowing (50 kg P ha^-¹) and high-nitrogen pellets at tillering (150 kg N ha^-¹). Fertilizers included (i) organic pellets (OF) enriched with agri-food by-products, (ii) organic-mineral pellets (OMF), and (iii) synthetic fertilizers (IN). Soil nutrient availability (P_ext, N-NH₄⁺, N-NO₃^-) and physico-chemical properties were assessed at day 0 and after harvest (210 days). Yield, grain quality, and greenhouse gas emissions (GHG) were monitored to evaluate the environmental impact of these fertilizers. The results showed that compost pellets combined with inorganic fertilizers achieved wheat yields comparable to conventional fertilization, maintaining grain quality while reducing GHG emissions in the OMF treatments. Therefore, organo-mineral pellet fertilizers represent a promising strategy for nutrient cycling in agroecosystems, reducing reliance on inorganic fertilizers and maintaining wheat productivity under Mediterranean conditions without increasing GHG emissions.