Multi-dimensional analysis of fertilizer-treated Satureja hortensis L. ecotypes: growth dynamics, biomass production, and phytochemical fingerprints

This study investigated how ecotype-specific fertilization affects growth, pigment accumulation, and essential oil (EO) composition in Satureja hortensis . We tested the hypothesis that organic manure and NPK nutrient inputs differentially regulate vegetative and reproductive traits across ecotypes. Soil at the experimental site was slightly alkaline (pH 7.5) and had low organic carbon, nitrogen, and available phosphorus. These conditions indicated a nutrient-limited environment that was likely responsive to fertilization. Three ecotypes, Mashhad, Shiraz, and Karaj, were evaluated under five fertilization regimes: control, organic manure at 25 and 50 t ha⁻¹, and NPK at 50 and 100 kg ha⁻¹. The experiment was arranged as a factorial randomized complete block design with three replicates. Key morphological, physiological, and phytochemical traits were analyzed using ANOVA, PCA, and SEM. The results showed significant effects of ecotype and fertilization. Significant ecotype × fertilizer interactions were observed for reproductive and pigment-related traits. Shiraz × O50 showed the greatest vegetative growth, leaf biomass, and chlorophyll a content. In contrast, Karaj × CH100 showed a higher number of flowers and anthocyanin content, while CH100 was associated with higher EO percentage. These responses suggest distinct allocation patterns between biomass-related traits and EO-related traits rather than a uniform response to fertilization. PCA identified coordinated growth–biomass and metabolite-related modules. SEM further indicated positive associations between physiological, phytochemical, and EO-related traits, whereas phenology was negatively associated with EO percentage. Under the tested field conditions, fertilization responses varied among ecotypes, indicating the potential value of ecotype-specific nutrient management. Organic manure mainly favored biomass production and pigment accumulation, whereas high-rate NPK favored EO percentage and reproductive traits. These findings provide insights into ecotype-dependent responses to fertilization under the evaluated conditions. However, the results are based on a single location and growing season. Further multi-location and multi-season studies are needed to clarify the mechanisms underlying fertilizer-induced changes in EO composition. Not applicable.