|By Dr. Rabindra Pandey
Medical Officer, Department of Ayurveda
Nepal lies in the central sector of great Himalaya between latitude 26.22 – 30.27 N and longitudes 80.04-88.12 E. It occupies an area of 147181 sq. Km. it has an average length of 884 km at Kechakalan, Jhapa to 8848 m at Sagaramatha the highest peak of the world. The temperature varies from extreme hot in the tropical plains to arctic frost in the mountain regions. These variations of climate soil and altitude are responsible for the amazing range of natural vegetation of the country.
Nepal is rich in medicinal and aromatic plants because of the favorable climatic conditions and hence has been a major source for the herbal plants. These medicinal plants contribute to the local and national economy through the generation of employment and generation of income for local farmer's collectors, traders and processors.
The invaluable natural resources are depleting steadily due to over exploitation, poor collection methods non sustainable uses, early harvesting and lack of knowledge on the post harves technology. There area not scientific efforts to replenish these natural resources of medicinal plants in the Himalaya regions. Modern agricultural technology should be provided to the farmers of various Himalaya regions for sustainable production.
The Himalaya region lies in the northern part of the country stretches from the east to west of Nepal. This region compromises sub alpine and alpine ecological zones. The lower parts has summer grazing pasture land where as the upper part has high altitude plants, with species which are adapted to with standing the extremes of cold and desiccation. Heavy snowfall takes place during winter moths. Above 5,000 m the places are covered with perpetual snow and no trace of important vegetation can be seen.
Beyond 6,000 m even these are not found and this region is called arctic desert of Neural zone.
There are mainly two principle of farming/ conservation of medicinal plants.
1. In situ conservation/ farming
In situ conservation/ farming means conservation of ecosy stems and their natural habitats and maintenance and recovery of viable populations of specie and their surroundings. It also comprises conservation of domesticated or cultivated species. The plant species that can grow there properly but number is less, can be planted there. Plant can be planted in forest, pasture land and protected area.
2. Ex situ Farming/ conservation
Due to over population and over collection of selected valuable plants for commercial purpose, it is not possible to conserve some plants in their own their natural environment. In this method plants/ seeds are collected from different parts provided artificial favorable environment and planted.
In Himalayan region it is the most important method for the cultivation of medicinal plants. Due to unique climate most valuable medicinal plants are found in this region. Land is covered by snow about 4-6 months of the year so it takes too long time to complete one life cycle of plants. To get suitable temperature the seeds have to wait long time for their germination. After germination saplings are also affected by heavy snow fall. To overcome these difficulties in Himalayan regions some methods of cultivation of plants are:
1.Seeds are sown in the nursery providing suitable temperature.
2.After germination and attaining appropriate size, plants are transplanted to natural environment. Sapling is provided to the farmers. It helps for the mass production of medicinal plant. The cultivation method of medicinal plants varies from plant of plant. Some plant prefer very cool climate some moderate climate and some plant prefers hot climate for their germination, growth, development, maturation, flowering and fruiting. Some plant needs specific host for their growth for example yarsagumba ( cordiceps sinesis) needs caterpillar.
3.Perennial plants are cultivated once and we can get benefit after at least one year.
4.In crop rotation method, plant is cultivated alternatively in same land year after year.
5.In intercropping method medicinal plants are planted with major crops.