Meta-Analysis Of Soil Properties Influencing Curcumin Content In The Curcuma Genus: Statistical Evaluation

Abstract

Curcumin, the principal bioactive compound of Curcuma species, is widely recognized for its pharmacological importance, yet its accumulation is highly variable and influenced by environmental and soil factors. This study conducted a meta-analysis to evaluate how soil parameters like pH, nitrogen (N), phosphorus (P), potassium (K), organic carbon (OC), and the carbon-to-nitrogen (C:N) ratio affect curcumin content across species of the Curcuma genus. Relevant studies were retrieved from PubMed, Google Scholar, and specialized plant science journals following defined inclusion criteria. Statistical analyses, including Spearman correlation, linear regression, and one-way ANOVA, were employed to examine the relationships between soil properties and curcumin concentration. Results demonstrated that potassium (K) exhibited the strongest positive association with curcumin content (r = 0.772, p < 0.001; β = 1.9433), whereas N, P, pH, and organic carbon showed negligible or non-significant effects. The dataset was limited in sample size and largely concentrated in South Asian regions, particularly India, with notable gaps regarding Curcuma caesia Roxb., a species of emerging pharmacological interest. These findings highlight potassium as a key soil determinant of curcumin biosynthesis and provide practical insights for optimizing turmeric cultivation through targeted soil management strategies. However, further interdisciplinary research incorporating climatic, genetic, and microbiome factors is needed to validate and expand these conclusions. This meta-analysis contributes to the growing field of agro-pharmacology by consolidating fragmented evidence and identifying actionable soil parameters relevant to both agricultural productivity and medicinal value.