Effects of applications of N fertilizers and nitrification inhibitors on dry matter and essential oil yields of Java citronella (Cymbopogon winterianus Jowitt.)

A field experiment was conducted for 2 years (1993-95) at Central Institute of Medicinal and Aromatic Plants, Field Station, Bangalore, India to evalu ate the nitrification inhibitors, benzotriazole, o-nitrophenol, m-nitroanil ine and dicyandiamide in a perennial aromatic grass, Java citronella. Citro nella responded to applications of high doses of nitrogen (300 kg N/ha/year ). The interaction between N doses and nitrification inhibitors was signifi cant. Nitrification inhibitors performed better at the highest N dose (450 kg N/ha/year) and the increase in the essential oil yields was to an extent of 27.3 to 34.6 % when compared with 'N alone' treatment. The nitrificatio n inhibitors also increased the apparent N recoveries by citronella conside rably. The oil content in the herb and its quality were not affected by the treatments. The nitrification inhibitors increased citronella yields and i mproved N economy.