Growth, biomass and petroleum convertible hydrocarbonsʹ yield of Grindelia camporum planted on an alluvial soil (Entisol) of North India and its response to sulphur fertilization

Four-week-old seedlings of Grindelia camporum Greene were planted in a mild calcareous alluvial soil collected from Mahibullapur, in Lucknow district (26° 30′ N latitude–80° 30′ E longitude) in pot culture. The soil, rated sulphur deficient on the basis of available soil sulphur, was fertilized with calcium sulphate to provide sulphur at the rate of 10, 25, 50, and 100 mg kg−1 soil. Observations on growth (height, branching, leaf area) were recorded periodically. Plants were harvested 26 weeks after transplantation (wat) and measured for biomass and biocrude yields. After harvest, the pot soil was measured for available sulphur using three extractants: 0.15% CaCl2, 0.5 M NaHCO3, pH 8.5, and Morganʹs extract. tive soil (control) is rated deficient in available sulphur; and availability of sulphur increased with increasing levels of sulphur fertilization. The vegetative growth of plants reached the maximum in response to sulphur amendment at the rate of 50 mg kg−1 soil 14 weeks after transplantation to pots. At the time of harvest, 26 weeks after transplantation, plants showed best growth and maximum number of capitula and weight, in response to sulphur amendment at the rate of 100 mg kg−1 soil. Thus, G. camporum showed a higher requirement of sulphur during the reproductive phase than for its vegetative growth and biomass yield. Maximum biocrude yield, both the total and ethyl acetate and methanol extractable fractions, was also obtained when sulphur was applied at the rate of 100 mg kg−1 soil.