A Carbon-Fixing and Nitrogen-Retaining Bio-Organic Fertilizer and Its Preparation Method

A method for preparing a Carbon-Fixing and nitrogen-retaining bio-organic fertilizer, comprising the following steps:

• (1) crushed corn stalks and polyvinyl alcohol resin with a solution containing potassium carbonate and potassium hydroxide are mixed, dried and carbonized in a nitrogen atmosphere at 700-800° C. in a carbonization furnace, to obtain activated biochar;
• (2) The activated bio-charcoal is immersed in a mixture of H2O2 and Cobalt(II) Ethylenediaminetetraacetate (Co-EDTA);
• stir the mixture for 2-4 hours, grind it to obtain a hierarchical porous structure product;
• (3) The hierarchical porous product prepared by step 2 is mixed with a composite microbial consortium and stirred for 1-2 hours to yield modified biochar;
• the composite microbial consortium comprises Azotobacter chroococcum, Pantoea ananatis, and Aspergillus niger;
• (4) The modified bio-charcoal obtained by step 3 is immersed in a solution of tetraamminecopper(II) sulfate and Mo-EDTA complex, and stirred for 1-2 hours to obtain loaded biochar;
• (5) The loaded biochar is fully mixed with perilla biomass extract and animal manure, and stirred for 20-30 minutes, concentrated to obtain the final carbon-fixing and nitrogen-retaining bio-organic fertilizer;
• wherein the mass ratio of corn stalks to polyvinyl alcohol resin in step (1) is 100:(1-10), and the carbonization temperature is 700-800° C.;
• wherein the perilla biomass extract is prepared by mixing perilla with water (5-60 g/L), stirring for 10 minutes, and heat-treating the liquid at 80-120° C. for 2-3 hours.