Agronomic Performance, Oil Yield and Hydrolate Quality of Patchouli Cultivated in Different Soil Covers

This study describes the evaluation of the effectiveness of different soil covers on the development, productivity, yield and metabolic content of patchouli oil (Pogostemon cablin) and its hydrolate. The agronomic experiments were carried out in the field, including four types of soil cover and six replications (4 x 6), using green cover (peanut), straw (crotalaria and millet straw), white plastic cover, and no mulch (weeding). After transplanting, the initial growth of seedlings was analyzed through weekly monitoring of plant height, stem diameter, and the number of leaves. At harvest time, the harvest yield (green mass) was performed. After drying the leaves, the oil and hydrolate were extracted by steam distillation and then the yield of patchouli oil was determined. Regarding the agronomic analyses, white plastic and straw coverage was superior to the other treatments, with higher plant heights, number of leaves, whereas the plastic and straw coverage was superior to the other treatments, with higher plant heights, number of leaves and green mass yield. The metabolic content was evaluated using High Resolution Mass Spectrometry (HRMS), and the chemical markers were identified through the analysis of the MS/MS fragmentation spectra and chemotaxonomic data. No significant differences were observed in the essential oils yields and their hydrolates and the intensities of the major ions found in the samples identified as chemical markers for the quality control of P. cablin.