Seed germination index of the product of kitchen waste biochemical equipment and its influencing factors

Objective  To determine the relationships between maturity, Na⁺, small molecular organic acids of product of kitchen waste biochemical equipment and germination index (GI), promote the resource utilization and popularization of the product of kitchen waste biochemical equipment, and at the same time, exploit the new technological way of carbon neutrality through soil carbon sequestration.

Method  The GI of product of kitchen waste biochemical equipment was determined using radish (Raphanus sativus) seeds, and the effects of Na⁺ and small molecular organic acid solutions on GI were analyzed by mimic experiments.

Result  The GI of the kitchen waste biochemical equipment product was 1.53%, which did not reach the standard of basic maturity of compost (GI ≥ 50%). When the extract of kitchen waste biochemical equipment product was diluted for 10 times, the Na⁺ content in the solution was 75.25 mg/L, and the GI value was 43.73%. With the increase of sodium concentration, the GI value showed a downward trend. When the Na⁺ concentration was 1 200 mg/L, the GI value was 52.86%. With the increase of the concentration of small molecular organic acids, the GI value showed a downward trend. When the concentrations of acetic acid and lactic acid were higher than 100 mg/L, and while the concentrations of propionic acid and butyric acid were higher than 50 mg/L, the GI value was less than 50%. The inhibiting effect of propionic acid and butyric acid on GI was stronger than that of acetic acid and lactic acid.

Conclusion  The GI of product of kitchen waste biochemical equipment did not reach the maturity standard of composting, and the main restriction factor was the small molecular organic acids produced by the degradation of kitchen waste, rather than its salt content.