WATER REQUIREMENT AND PRODUCTIVITY OF PALMAROSA ON SANDY LOAM SOIL UNDER A SUBTROPICAL CLIMATE

Water requirement, productivity and water use efficiency of a perennia l aromatic grass, palmarosa (Cymbopogon martinii stapf cv motia), were studied under different levels of irrigation (0.1, 0.3, 0.5, 0.7, 0.9 , 1.1, 1.3 and 1.5 IW:CPE ratio) for three years (July-June) during 19 90 to 1993, on sandy loam soils under subtropical climate of Lucknow. Growth, herb and essential oil yield increased significantly up to 0.5 IW:CPE ratio. At 0.5 IW:CPE ratio palmarosa produced 47.3 tons of fre sh herb and 227.3 kg of essential oil ha(-1) yr(-1). Further increase in irrigation levels caused an adverse effect on growth and yield of p almarosa. Irrigation levels did not affect the quality of oil in terms of its geraniol and geranyl acetate contents. Water requirement of pa lmarosa was worked out to be 89.1 cm. The highest water use efficiency of 2.97 kg oil ha(-1) cm(-1) was recorded at 0.1 IW:CPE ratio, at 0.5 IW:CPE ratio (optimum) it was 2.55 kg oil ha(-1) cm(-1). Irrigation s cheduled at 0.5 IW:CPE ratio gave the highest net return of Rs 51 963 ha(-1) yr(-1). (C) 1997 Elsevier Science B.V.