Commercial Cultivation of Lemongrass (Cymbopogon flexuous) for oil production
Lemongrass crop - Lemongrass information
Lemongrass was originally used for flavoring food in Asia, and crushed leaves were used as a hair wash. Systematic cultivation and distillation of Lemongrass started in the late 1880s in Kerala, India. The oil is used in scenting soaps, detergents, and a variety of products with lemon-like odor.
The following two species are mainly used for lemongrass oil:
- Cymbopogon citratus (DC.) Stapf. produces West Indian lemongrass oil. It is mainly grown in Argentina, Honduras, Brazil, Guatemala, Haiti, Indonesia, Malaysia, Sri Lanka, and Vietnam, and to some extent in the Philippines, China, India, Myanmar, Bangladesh, and northwestern Australia (1).
- Cymbopogon flexuosus (Steud.) Wats., which produces East Indian lemongrass oil. It was mainly cultivated in southern India, especially in Kerala, and is currently cultivated in many other states. It is also cultivated in Indonesia and Madagascar (1).
The main constituent of lemongrass oil is citral which is above 75% and is used in synthesis of ionones which are used in production of several aromatic compounds.
Lemongrass is a perennial grass that can be cultivated and harvested for over five years. It can grow up to 3 m in height with stiff stems. However, it is harvested much before the stems stiffen since they do not contain oil at that phase.
Agro-climatic requirements of Lemongrass
Lemongrass is a versatile crop that can be cultivated in various soil and climatic conditions. But it prefers humid, sunny, warm, and high rainfall conditions. Sandy loam soils are preferred, though it can grow in lateritic soils. Since it is hardy, lemongrass is usually cultivated in marginal soils where other crops do not grow well. A wide range of soil pH conditions support a good crop of lemongrass, with 5.5-7.5 pH being the most optimum and commonly preferred. Using suitable soil management methods, lemongrass can also be grown in saline and alkaline soils.
Sowing/transplanting of Lemongrass
Lemongrass is usually propagated by slips and sometimes by seeds. The slips are planted in the field (pic) at a spacing of 45x45 cm on ridges or raised beds. Nearly 50,000 slips are required for planting 1 ha. Either the planting is done on a rainy day or a light irrigation is given soon after planting. It is essential to maintain plant population. If and when necessary, gap-filling should be done.
Preparation of lemongrass slips
Planting of lemongrass slips in the field
Nutrient Requirements of Lemongrass- How to Fertilize Lemongrass
It is important to test the soil for its nutrient status and apply the necessary amounts of fertilizer and manure according to an agronomist's recommendation.
In soils of medium fertility, a lemongrass farmer can apply:
- 10 tons of farmyard manure per hectare per year
- 150 kg N/ha/year in the form of urea or other sources,
- 40 kg P2O5 in the form of single superphosphate or other sources and
- 40 kg K2O in the form of Muriate of Potash (MOP) or other sources
- secondary and micro-nutrients, as per the advice of an agronomist (and the soil analysis results)
Generally, all farmyard manure, P, K, and 1/3 of N are applied at the time of planting. The rest of N is applied at two-monthly six equal splits. It is essential to address deficiencies of secondary and micronutrients to derive good yields and quality lemongrass.
Integrated nutrient management (a combination of organic and inorganic fertilizers) improves lemongrass's growth and yield. If organic cultivation of lemongrass is followed, the use of vermicompost along with bio-inoculants helps to derive good yields.
Weeding in Lemongrass - lemongrass weed management
The field should be kept free of weeds till a complete cover of the crop is obtained. Earthing up the plants after about four months and again after every harvest is beneficial.
Irrigation of Lemongrass - lemongrass water needs
A light irrigation is required soon after planting. In non-rainy periods, irrigation by surface, sprinkler, or drip methods is given at 10-day intervals (1 inch or 25.40 mm).
Intercropping with Lemongrass
In the initial stages of Lemongrass, when its growth is slow, short-lived legumes such as black gram and green gram can be intercropped (Pic.) and can be co-cultivated in the field. Such practice does not affect the yield of Lemongrass and, at the same time, gives extra income to the farmer.
Intercropping of legume in Lemongrass
Lemongrass harvesting
Lemongrass is a perennial crop and can sustain for more than seven years; however, the crop is maintained for 5 years for economical production. The crop is harvested by cutting 10-12 cm above ground level. Two harvests can be taken in the first year; 8 - 9 months after planting and 3 to 4 months after the first harvest. From second year onwards, three to four harvests can be taken per year at 3 to 4 months interval.
Harvesting of Lemongrass has to be synchronized with the accumulation of oil in the plant and citral in the leaves. It has been shown that optimum oil accumulation and citral synthesis takes place in two to five months depending on the season (2). During the winter season, citral accumulation is slow, and it is recommended that early harvest of Lemongrass be avoided.
Lemongrass yield
Lemongrass yields nearly 20 to 35 tons of fresh grass/ha/year. At an oil recovery of 0.8-1.0 %, lemongrass yields 160 to 200 kg oil/ha in the first year and, from the second year onwards, 200 - 240 kg oil/ha/year.
References
- Weiss, E. A. (1997). Essential Oil Crops. CAB International, Wallingford, UK, pp. 86-103.
- Prakasa Rao, E.V.S., K. Puttanna, R.S. Ganesha Rao and S. Ramesh (2005). Significance of harvest intervals on oil content and citral accumulation in variety Krishna of lemongrass (Cymbopogon flexuous). J. Medicinal and Aromatic plant Sciences, 27:1-3.
Further reading
Distillation of patchouli for essential oil – Patchouli essential oil extraction
Patchouli cultivation guide – How to grow Patchouli Commercially for oil
Distillation of Sweet Basil for Essential Oil
Commercial Cultivation of Sweet Basil (Ocimum basilicum) for oil production
The Role of Herbal Leys in Sustainable Agriculture: Boosting Yields and Soil Health
