Effect of nitrogen, irrigation and season of planting on herbage, oil yield and quality of South American marigold (Tagetes minuta L.) grown on alfisol

Summary

Field experiments during 1998–1999 and 1999–2000 on red sandy loam soil (alfisol) in the semi-arid tropical climate of South India, studied the effect of nitrogen application, irrigation and season of planting on herbage and oil yield of South American marigold (Tagetes minuta L.). The application of nitrogen at 200 kg ha^–1, irrigation at 0.5 IW: CPE ratio (irrigation water: cumulative pan evaporation) and autumn planting produced significantly higher herbage and oil yields. Oil content was not infiuenced by nitrogen, irrigation or by season of planting. The composition of tagetes oils from main and ratoon crops differed. Cis-β-ocimene and cis-tagetenone concentrations were higher in the main crop and concentrations of limonene, dihydrotagetenone and cis-tagetenone were higher in the ratoon crop.