Characteristics of industrialized hydrothermal cracking solid organic fertilizer and its effects on fresh corn growth

Traditional methods of producing organic fertilizers result in significant nutrient loss and greenhouse gas emissions, making it challenging to align with sustainable development and the achievement of net-zero emissions goals. Hydrothermal cracking, as a novel clean technology for the utilization of organic waste into fertilizer, has been extensively studied and refined in laboratory settings, but its large-scale industrial evaluation remains limited. This study investigates the properties and field application of hydrothermal cracking solid organic fertilizer (HCSOF) produced at a pilot scale with an annual output of 10,000 tons. The results indicate that the organic matter content and total nutrient content (TN + P₂O₅ + K₂O) of HCSOF reached 50.6 % and 5.46 %, respectively, which are 20.6 % and 1.46 % higher than the standards for organic fertilizers in China. Additionally, contaminants such as pathogens and antibiotics in the product were completely eliminated. Elemental analysis and pore size distribution highlighted the unique adsorptive attributes of HCSOF, which showed significant effect in reducing soil ammonium nitrogen. Results from field trials indicate that the complete substitution of chemical fertilizers with HCSOF did not reduce corn yield, which remained at 9.03 t/ha. Particularly, compared to the exclusive use of chemical fertilizers, HCSOF treatments resulted in a 7.03 % and 4.70 % decrease in fresh corn lodging and disease incidence, respectively. Antibacterial tests further confirmed its ability to counter pathogens. This study provides robust evidence for scaling up hydrothermal cracking fertilizer production from laboratory to industrial levels. Future research should focus on multi-batch sampling and extended field experiments.