Productivity of menthol mint (Mentha arvensis) and wheat (Triticum aestivum) as relay and sequential cropping system under different irrigation scheduling

A field experiment was conducted at Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India during 2014–15 and 2015–16 to assess the impact of irrigation schedules (IW: CPE 0.6, 0.8, 1.0 and 1.2) on mentha (Mentha arvensis L.) growth, productivity, profitability and irrigation water productivity under variable cropping systems (sole mint, wheat + mentha relay cropping and wheat-transplanted mint). Sole mint recorded the maximum values of all the growth parameters, with an exception in leaf: stem. It also produced the maximum fresh herbage (22, 170 kg/ha) as well as the oil yields (196.6 kg/ha). The maximum oil content (0.96%) was obtained with transplanted mint crop. Relay cropping of mint with wheat in 2: 1 row pattern recorded the maximum mentha oil equivalent yield (MOEY), net return (143.5 × 10³ /ha)) and benefit: cost ratio (2.08). Irrigation water productivity was found maximum (5.35 kg oil/ha-cm) with sole planting of mentha. Irrigating the crop at 1.2 irrigation water (IW) to cumulative pan evaporation (CPE) ratio registered significantly highest plant height, leaf area index, lateral spread, dry matter accumulation, fresh herbage and oil yields. Oil content and leaf: stem expressed a declining trend with increasing the irrigation frequency under wider IW: CPE. Irrigation at IW: CPE 1.2 gave the maximum MOEY (233.4 kg/ha), net return (134.4 × 10³ /ha) and benefit: cost ratio (1.93). However, the maximum irrigation water productivity was realized at 0.6 IW: CPE. Wheat + mentha relay cropping (2: 1) at IW: CPE 1.2 was better option than others with respect to MOEY and economics.