Influence of Different Nitrogen Treatments on the Growth and Yield of Ocimum

A factorial randomised block designed experiment was conducted to evaluate the effect of different levels of nitrogen on growth, herb and seed yield of three species of Ocimum, namely O. sanctum (Holy Basil), O. basilicum (Sweet Basil) and O. amaricanum (Wild Basil or Black Tulsi) with the objective to select the better species under local conditions which ultimately improve the production of the crop. The treatments consisted of four levels of nitrogen, namely 0 (control), 50, 100 and 150 kg N/ha. A uniform basal dose of phosphorous and potassium fertilisers was given to the soil before transplanting at the rate of 20 kg P/ha and 30 kg K/ha, respectively. The sampling was done at 50, 70 and 90 days after transplanting (DAT). The different parameters such as plant height, number of branches per plant, fresh and dry herb yield per plant were investigated at different sampling stages, whereas the yield parameters like oil content in herb, seed and oil yield were measured at harvest (90 DAT). It is revealed from our results that N3 and S3 were found the best among all the tested treatments. However, the interaction (S3 × N3) excelled among all the interactions studied. Thus, the application of nitrogen at the rate of 150 kg N/ha could be recommended for maximising herb and oil yields of Ocimum plants under local agro-climatic condition.