Effect of nitrogen and phosphorus levels on plant growth and yield attributes of clary sage (Salvia sclarea L.)

A field study was conducted in the temperate climate (Western Himalayan region of Kumau) of India to study the effects of different nitrogen and phosphorus levels (0, 50, 100, 150 kg ha-1 of nitrogen and 40, 60, 80 kg ha-1 of phosphorus) on growth, herb yield, spike yield, oil yield, essential oil quality, and output per unit of fertilizer on clary sage (Salvia sclarea L.). Efforts were made to elucidate the economics of N application through marginal analysis. Observations revealed that growth, and yield attributes increased with increasing levels of N and P fertilizers. The marginal profit earned per dollar invested on N fertilizer application varied with treatments, and at N100 kg ha-1 plus P60 kg ha–1 earned maximum profit $ 1.33. The quality of essential oil was not influenced by fertilizer application and acceptable in aroma industry. It is suggested that further research should be done under different environmental conditions.