This study reveals critical methodological and statistical flaws that undermine its validity. The response surface model includes non-significant interaction and quadratic terms (p > 0.05), likely inflating the adjusted R² (0.9637) without meaningful impact. Additionally, the lack of fit of the model has not been reported, making it difficult to assess the model’s validity. Key design details, such as randomization and replication, are missing, raising concerns about bias. Variability in AHA yields under identical conditions and the absence of error propagation analysis further question reproducibility. Moreover, the narrow experimental parameter ranges lack justification compared to broader studies, and comparisons with natural humic acids are inconsistent. These issues cast doubt on the reliability of the findings and their broader applicability.
