Maximizing Essential Oil Yield and Quality in Menthol Mint (Mentha arvensis L.) by Reducing Water Requirement through Deficit Irrigation Practices

Menthol mint (Mentha arvensis L.) is an aromatic and medicinal plant worldwide cultivated for high-value essential oil.  It comes under angiospermic plant and belongs to family Lamiaceae commonly known as Japanese mint. The high-value essential oil is obtained from the stem and leaf of plant by the process of hydro-distillation through which major ingredient L-menthol is obtained that is used in aroma and pharmaceutical industries. This investigation aimed to reduce water requirements which can enhance its productivity for sustaining menthol mint cultivation in India. The present investigation has been undertaken as treatment combination which includes two varieties viz. i) Kosi and CIM-Kranti; three depths of soil moisture viz. i) ۳ cm, ii) ۶ cm and iii) ۹ cm along with three moisture regimes, i.e., i) ۲۰±۵%, ii) ۴۰±۵%, and ۶۰±۵% available soil moisture (ASM) were tested in split-split plot design during ۲۰۱۸ and ۲۰۱۹ (from February to June). Results from the present study revealed that the maximum oil yield was recorded ۱۱۶.۷۸ kg ha-۱in cv. Kosi and ۱۰۷.۲۳ kg ha-۱ in cv. for CIM-Kranti, whereas menthol yield was recorded ۸۹.۲۳ kg ha-۱in cv. Kosi and ۸۵.۱۳ kg ha-۱in cv. CIM-Kranti under ۶ cm depth of irrigation when applied irrigation at ۴۰±۵% available soil moisture (ASM) in menthol mint. However, the lowest water requirement was recorded ۱۱۸ mm in cv. Kosi and ۱۴۸ mm in cv. CIM-Kranti. The highest water use efficiency was recorded ۰.۶۱ in cv. Kosi and ۰.۵۱ kg oil ha-۱ mm-۱ in cv. CIM- Kranti under ۳ cm depth of irrigation and when irrigations were applied at ۲۰±۵ % ASM. The highest net returns of ۱۱۴۰.۹۱ ha-۱ and ۹۸۹.۷۰ ha-۱ have been recorded in Kosi and CIM-Kranti, respectively were computed at ۶ cm depth of irrigation and when irrigations were applied at ۴۰±۵% available soil moisture as compared with other treatments. The irrigation depth (۶ cm) applied at ۴۰±۵% ASM was found to be a perfect combination for obtaining maximum oil yield, water use efficiency, net returns, and benefit-cost ratio.

Keywords:

Available soil moisture , depth of irrigation , Economics , menthol mint , Water Requirement , Water use efficiency