Effect of Soil Type on Grapefruit and Shaddock Essential Oils

Abstract

Grapefruit and shaddock essential oils (EOs) have remarkable biological activities. Soil types are characterized by various properties which affect the essential oils of grapefruit and shaddock. Many Citrus species are cultivated in the Nile Valley of Egypt, which is characterized by its clay soil, but there are no large areas cultivated with both grapefruit and shaddock. The reclaimed desert in Egypt which characterized by sand soil is expanded by planting many Citrus species, which produce different residues such as leaves, flowers, and peels rich in essential oil, which is used in the production of natural raw materials as a source for medicine and food. Thus, the variations of grapefruit and shaddock essential oils and their constituents were evaluated under sand and clay soils to find out the extent of the opportunities for expanding their cultivation in the new reclamation region as a natural source of EO. The leaves, flower, and peel EOs of grapefruit and shaddock were isolated by hydro-distillation and analyzed by gas chromatography and gas chromatography/mass spectrometry; data were statistically analyzed by one-way analysis of variance. Samples collected from trees grown in sand soil produced the greatest amounts of essential oil in both species whatever the organ from which this oil was extracted. Limonene was of the major compound in both peel and flower grapefruit essential oils, while sabinene was the predominant one in leaves EO (39.8% and 44.8%, in clay and sand soils respectively). E-phytol, linalool, and limonene were the predominant constituent in leaves, flower, and peel of shaddock essential oil, respectively. Various identified constituents in leaves, flowers, and peels noteworthy the presence of oxygenated diterpenes in percentage not less than 33% in leaves shaddock essential oil which was completely omitted in the other organs and in the grapefruit EOs. The monoterpene hydrocarbon was the major chemical class in various essential oils of grapefruit; oxygenated diterpenes, oxygenated monoterpenes, and monoterpene hydrocarbon were the main chemical classes of leaves, flower, and peel essential oils from shaddock, respectively. In the essential oil contents (%), most of the main constituents and major chemical groups were higher under sand soil than clay soil. This study serves as a reference for selection the suitable soil to produce the essential oil according to the components of interest; also, this trial recommends the cultivation of both species in reclaimed sand soil of Egypt.

Effect of foliar application of seaweed (organic fertilizer) on yield, essential oil and chemical composition of coriander

“…The high sand content in the soil caused an increase in the essential oil ratio and yield (location B) and these results are similar to other studies, which showed that soil stress conditions like high pH, drought, low nutrients, sand, and salinity caused an increase in essential oil ratios [ 42 – 44 ]. Likewise, Aboukhalid et al [ 45 ] reported that the quality of essential oils was affected by soil structure.…”

“…Aziz et al [ 46 ] and Said-Al Ahl et al [ 47 ] also observed that essential oil components ratio of Thymus vulgaris L. were higher when cultivated in loamy soil than in clayey soil. Khalid and Ahmed [ 44 ] had also similar results on citrus plants. In this study, it was also claimed that when the amount of sand increased, the essential oil ratio and yield also increased.…”

Chemical composition of the essential oils isolated from Phlomis olivieri Benth (Lamiaceae) in four western provinces in Iran

“…One of the factors that can be very involved in this field is the type of weather and region (Figueiredo et al, 2008;Mehalaine et al, 2021). Soil characteristics are influential in this field, and in rich soils, the number and variety of secondary compounds is greater (Khalid & Ahmed, 2021). These factors have significant effects on the quality and quantity of plant essential oils.…”