Espinoza, A.L.F.; Raniro, H.R.; Leite, C.N.; Pavinato, P.S. Physico-Chemical Properties and Phosphorus Solubilization of Organomineral Fertilizers Derived from Sewage Sludge. Soil Syst.2023, 7, 100.
Espinoza, A.L.F.; Raniro, H.R.; Leite, C.N.; Pavinato, P.S. Physico-Chemical Properties and Phosphorus Solubilization of Organomineral Fertilizers Derived from Sewage Sludge. Soil Syst. 2023, 7, 100.
Espinoza, A.L.F.; Raniro, H.R.; Leite, C.N.; Pavinato, P.S. Physico-Chemical Properties and Phosphorus Solubilization of Organomineral Fertilizers Derived from Sewage Sludge. Soil Syst.2023, 7, 100.
Espinoza, A.L.F.; Raniro, H.R.; Leite, C.N.; Pavinato, P.S. Physico-Chemical Properties and Phosphorus Solubilization of Organomineral Fertilizers Derived from Sewage Sludge. Soil Syst. 2023, 7, 100.
Abstract
Sewage sludge is an organic waste generated in waste-water treatment plants with certain content of nutrients, what may potentially be used as a source of slow release fertilizer, especially as phosphorus (P) source, but it demands some pre-treatment and the content of P is much lower compared to soluble mineral fertilizers. For these reasons, composted sewage sludge was used to manufacture pelletized organomineral fertilizers, mixing it with the inorganic sources monoammonium phosphate (MAP) and AshDec® (ASD) (thermochemically incinerated sewage sludge). The fertilizers were physiochemically characterized and evaluated as to the dynamics of soil P solubilization, and the forms of P remaining according to its lability. The sources evaluated were: organic compost of sewage sludge powder (SSC), pelletized SSC (SCP), pelletized organominerals SSC+MAP (S+MAP) and SSC+ASD (S+ASD), ASD alone, all compared to a soluble mineral fertilizer (MAP), and a control without P fertilizer. A test was conducted in leaching columns with 50 g of soil (Oxisol), where the fertilizers were applied at a dose of 100 mg P/column, and 30 mL of water or 2% citric acid were added daily for 30 consecutive days. The collected leachates had pH measured and P content determined. Pelletizing process resulted in denser products and promoted more gradual P release. The organomineral S+MAP was the most water-soluble recycled source, solubilizing about 70% of the total P, while the others presented much lower solubilization (<20%). In contrast, all fertilizers showed high solubility in 2% citric acid (except for S+ASD). After leaching, the greatest amount of P remaining in the soil as labile and moderately labile. Composting and the AshDec process produced materials with slow P solubilization, which would be favoured to solubilize in acidic soils and acidic rhizosphere conditions. In turn, the organomineral mixture of SSC with a highly soluble mineral fertilizer (MAP) resulted in a promising product with intermediate nutrient solubility, better synchronized with crop demand, thus increasing efficiency in P use.
Keywords
P recycling, P bioavailability, organomineral, gradual release of P
Subject
Environmental and Earth Sciences, Waste Management and Disposal
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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