A case study on the influence of soil amendment on ginger oil’s physicochemical properties, mineral contents, microbial load, and HPLC determination of its vitamin level

Abstract This study thoroughly examined the effects of soil treatments on the soil geotechnical properties and ginger rhizome oil quality. Ginger was cultivated in soil subjected to four different treatment plans: one with organic manure (ORG 1), another with combination of organic manure and seaweed extract (ORG 2), a third with the NPK 15:15:15 fertilizer (CONV 1), and the last one with a blend of fertilizer and seaweed extract (CONV 2). The rhizomes were harvested at peak maturity, and their oil content was chemically analyzed using standard procedures. Additionally, the soil’s properties were evaluated during the experimental period. It was observed that the oil extracted from ginger rhizomes cultivated with organic treatments (ORG 1 and ORG 2) had higher vitamin and iodine levels but lower levels of minerals, acid content, density, specific gravity, refractive index, and peroxide values compared to the oil produced from conventionally cultivated ginger plants. Regarding the microbial pollution of the oil samples, all the ginger oil samples had 0 cfu/mL after incubation. The results depict that a substantial relationship exists between soil treatment and the oil quality. Furthermore, the results indicate that the organic treatments remediated the soil better than the inorganic treatments. Correlating soil properties with the crop performance is vital for identifying optimal soil conditions for producing high-quality oils.