Abstract
The conventional planting of menthol mint (Mentha arvensis L.) is done in January-February with suckers that are placed 5-7.5 cm deep in rows 45-60 cm apart. The crop takes 120-125 days to reach maturity. The practice delays planting of the succeeding rainy-season crop, resulting in poor yield. A field experiment on depth of sucker planting (2.5 cm, 5 cm, 7.5 cm, and 10 cm) was conducted for three consecutive years from 1999-2001 (February-May) at the research farm of the Central Institute of Medicinal and Aromatic Plants, Lucknow, India, to explore the possibilities of minimizing the maturity period of the crop. Plant height, plant spread, and root + sucker:shoot ratio were decreased with increasing depth of planting suckers at all stages of crop development; whereas, leaf:stem ratio showed the reverse trend. Crop planted at 2.5 cm depth produced the maximum herb and oil yield in 105 days, and took 10 and 20 days less time than those planted at 5 cm and 7.5 cm deep, which took 115 and 125 days to maturity, respectively. The highest net return [Rs 28 600 ha-1 (U.S. $1.00 = Rs 42)] was obtained from crop planted at 2.5 cm depth and harvested at 105 days after planting (DAP) followed by Rs 27 005 ha-1 obtained from suckers planted at 5 cm depth and harvested at 115 DAP. The highest net return of Rs 272.6 and 272.4 ha-1 day-1 was obtained from 2.5-cm deep-planted suckers harvested at 95 and 105 DAP, respectively. Planting of suckers at 2.5-cm depth is suggested for ensuring earlier maturity of menthol mint by 10-20 days, and for getting maximum net return per unit area and time. This may enable growers to accommodate the main Kharif crops after two harvests of menthol mint.
