Published online by Cambridge University Press: 01 September 1999
Two field experiments were conducted during 1996–98 at Bangalore, India to study the effect of soil moisture regimes (0·3, 0·6 and 0·9 IW:CPE ratios) irrigation water:cumulative pan evaporation (IW:CPE) ratios and three rates of nitrogen application (0, 100 and 200 kg/ha) and in another experiment, three soil moisture regimes (0·3, 0·6 and 0·9 IW: CPE ratios), two rates of nitrogen application (100 and 200 kg/ha) and modified urea materials [prilled urea (PU) and dicyandiamide coated urea (DCDCU)] on oil content, herbage, oil yield and quality of geranium grown on altisols. Soil moisture maintained at 0·6 IW:CPE ratio significantly increased the herbage and oil yields of geranium. Application of 200 kg N/ha gave the maximum herbage and oil yield compared with those obtained from 0 and 100 kg N/ha. DCDCU produced higher yield than PU. The concentration and quality of essential oil were not influenced either by soil-moisture regime, rates or carriers of N.