Evaluation of Dicyandiamide Treated Urea in Java Citronella

Java citronella (Cymbopogon winterianus Jowitt), a perennial, aromatic grass, responds to heavy N applications as N recoveries by this crop are usually poor. The present study was made in a field experiment on a Paleustalf to evaluate the nitrification in hibitor, dicyandiamide (DCD) in this crop. At the highest N level (400 kg N ha⁻¹ a⁻¹), urea treated with 15 or 20% DCD increased significantly the herb and essential oil yields over ordinary urea by 28 to 32 per cent. In general, higher ammoniacal and lower nitrate-N in the soil (0.0–0.3m) and higher NH₃ volatilization losses were observed with DCD treated urea. At 400 kg N ha⁻¹ a⁻¹ level, DCD-treated urea increased the apparent N recoveries. DCD can be effectively used in Java citronella at high levels of N applications and during rainy season in light soils.