In the present study, the groundwater quality for suitability in agriculture from Udham Singh Nagar district, Uttarakhand, has been evaluated. A total of 50 groundwater samples have been collected and analysed for pH, EC, TH, HCO₃⁻, CO₃²⁻, Cl⁻, SO₄²⁻, NO₃^–, Ca²⁺, Mg²⁺, Na⁺ and K⁺. To assess the groundwater quality for irrigation purpose, parameters like sodium adsorption ratio (SAR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), magnesium hazards (MHs), permeability index (PI), and chloroalkaline index (CAI) values have been calculated. In USSL diagram, most of the groundwater samples fall in the C2S1 category and were safe for irrigation purpose. Only seven groundwater samples fall in the C3S1 category, indicating medium to high salinity which is safe for irrigation purpose for all types of soils but with limited care of exchangeable sodium. On the basis of RSC, all groundwater samples were observed to be suitable for irrigation purpose. Piper diagram indicated that 50% of the groundwater samples belonged to the Mg²⁺-Ca²⁺-HCO₃⁻ type and 48% was classified as the Ca²⁺-Mg²⁺-Cl⁻ type. Durov diagram suggested possibilities of ion mixing and simple dissolution of ions from polluted soil.

The present study was aimed to investigate the effect of drying on the essential oil composition and oil content of Ocimum americanum L. For the study, the aerial parts of the plant were collected from Ranikhet, district Almora and dried using different drying methods until constant weight, i.e., sun-drying (26°C ± 5°C), shade-drying (20°C ± 5°C) and oven-drying (at 35°C, 45°C and 55°C). Fresh and dried samples were hydrodistilled using Clevenger apparatus and the essential oil obtained was analyzed by GC and GC/ MS. Essential oil content was found to be the highest for sun dried (0.7%) followed by oven dried at 55°C (0.3%), shade dried (0.2%), oven dried at 35°C (0.2%), oven dried at 45°C (0.1%) and fresh sample (0.1%). 1,8-Cineole (9.14-23.67%), methyl chavicol (5.70-16.34%), β-bisabolene (7.78-29.23%) and (Z)-α-bisabolene (2.32-17.49%) were the common major constituents of all the oils under different drying methods. The essential oil composition and oil yield were greatly affected by drying methods. Sun drying could be used as the most prominent drying method for O. americanum L. A significant amount of camphor (38.34%) and highest essential oil content was present exclusively in the essential oil of sun dried material.

Thymus serpyllum L., a well-known aromatic plant of the Himalayan region is often used in pharmaceutical, cosmetic, flavoring and fragrance industries because of its phenolic and non-phenolic constituents. The amount of these compounds varies with the origin, the climatic conditions and the developmental stage of harvesting time of the plant. Under different environmental conditions, plant specimen of the same species respond differently through production and accumulation of the primary and secondary metabolites. In the present work, T. serpyllum L. was collected from its natural habitat and grown at different agro-climatic zones, i.e., Auli (higher Himalayas; 2744 m asl), Pithoragarh (lower Himalayas; 1524 m asl) and Haldwani (foothill areas; 412 m asl). The essential oil from fresh aerial parts of cultivated plants at full blooming stage was obtained using Clevenger apparatus and analyzed by GC–FID and GC–MS. The amount of thymol was also quantified by HPTLC. The data were statistically analyzed using MS Excel and SPSS 16.0. The percentage yield of the essential oils varied from 0.20 to 0.84%. Thymol was the major compound found in all the three cultivations, being the highest for Haldwani (84.63%) followed by Auli (50.80%) and Pithoragarh (41.15%) cultivations. Camphor was the second major compound, only identified in Pithoragarh (36.34%) region. Alpha-thujene, p-cymene, alpha-terpineol, (E)-caryophyllene, beta-bisabolene, alpha-pinene and carvacrol were also identified in significant amounts. HPTLC quantification suggested the similar pattern of thymol percentage as obtained from GC–FID. The study revealed that there was a significant difference in the terpenoid constituents of the plant grown at different agro-climatic zones. Thymus serpyllum grown at lower altitude area (warm climatic zone) can be a potential source of thymol along with high essential oil yield.

The essential oils of ten wild growing Ocimum americanum L. of the family Lamiaceae collected from different locations in Uttarakhand, India, were analyzed by capillary gas chromatography (GC) and GC/mass spectrometry (GC/MS). On the basis of chemical composition and cluster analysis, O. americanum was classified into six groups. Group I was significantly rich in methyl chavicol, 1,8-cineole, (E)-γ-bisabolene, β-bisabolene and eugenol, while group II has (E)-γ-bisabolene, aliphatic hydrocarbons, eugenol, β-bisabolene and methyl chavicol as major constituents. Eugenol and (E)-caryophyllene were found in abundant quantity in group III and linalool with methyl chavicol in group IV. Group V contained aliphatic hydrocarbons, eugenol, camphor and 1,8-cineole in high content while camphor and aliphatic hydrocarbons were found in group VI. Linalool was positively correlated with methyl chavicol, while eugenol with (E)-α-bisabolene and β-bisabolene with (E)-γ-bisabolene. The essential oil composition of O. amercanum was found to be affected by variation in soil properties and microclimatic conditions.