Weed: A Scenario
The word weed, which came into existence with the human civilization, is generally employed for useless plants which grow side by side with the agriculture crops or forest lands. Weeds are plants which at a particular place and time are disliked by man. This is because these plants compete with other more desirable plants by acting as host to various pests and diseases. Weeds are also unpalatable or dangerous to domestic beasts. The dominant weeds of the Indian Himalayan region are Lantana, Parthenium and Eupatorium. Weeds are spreading in the Himalayan region at an alarming rate, adversely affecting large area of cultivable land.
Forest weeds no more can be ignored now. The deforested areas are largely covered by these plants. The majority of such land has infestation of undesirable plants having no use. In some places these plants have overstepped cultivated land and have also entered forest areas as lower/middle canopy.
Their presence is also now justified as green cover taking care of soil and water but by and large their growing menace against bio diversity, economic loss, and social disaster call for judicious attention. Weeds like Lantana, Parthenium and, Eupatorium etc have caused havoc in terms of social and Ecological losses. In many places villagers had to shift their hamlets because of severe infestation of Lantana.
Practically there have not been any efforts to review physical ecological and social status of rapidly growing weed menace. This also warrants some control measure initiative. Since most of earlier control task have almost failed, it is imperative to evolve other alternatives. There have recently been some efforts to explore local and commercial utility of such weeds. This has substantially been proved new source of local employment. Large area that we have under such species can be converted into resource for local employment. Long back community-forest lost relationship can be revived. This would not only help to generate biomass utility but would also control wild spread of such plants.
Weed as new set of biomass cannot be overlooked particularly in wake of alarming depletion of forest biomass. Growing scarcity of latter has prohibited several community day today utility of biomass. Forestry management strategy should now predominantly include weed management through involvement of local community. This is equally true that wildly growing weed can only be controlled through large number of community involvement and that too by subjecting it to local and commercial utility.
Some important measures will have to be taken with following focused issues.
Status survey of major forest weeds of the country in different agro-climate zones.
Abundance, intensity, ecological economical and social impact of weeds.
1. Local community utility
2. Some case studies of weed use.
3. Future Research and Development on weed use.
Lantana camara, Parthenim and Eupatorium
are abundantly available weeds of mountain region in Himalayas. HESCOens are always seeking the potential for weed use. Our major experiments are carried on lantana use.
Lantana, an offensive weed, is dispersing fast in the hilly region of Western Himalaya. In hilly regions, it has expanded wildly from lower altitude to higher areas upto 1800 m. above msl. The plant has become a serious threat to agriculture land and especially to ground flora in the forest.
The adverse effect Lantana has created is:-
It takes control of land immediately after invasion.
Being deep rooted it becomes difficult to uproot it.
As the plant is not utilized for any purpose, its enormous seed production and high survival rate further promote the species.
Burning and cutting of the plant encourages massive growth.
It does not allow any species to grow along probably due to dense canopy structure and allopathic effect of the species.
It harbours a hideout for wild animals.
Animal gazing over the species get poisoned.
Various attempts to control the species have been launched including biological and mechanical means. But none of them have been able to check the growth of the species.
The effective control measure
HESCO’s intervention to control the species took an interesting turn when it subjected the species for local and commercial utilization. In this search, the following set of technologies were worked out to make use of the plant.
Cheap furniture- from stick
Utility articles- from stick
Incense materials- from leaves
Mosquito repellent- from leaves
Power generation through gasification.
The cheap furniture made from Lantana is popular today. This technology is well established now.
Sticks of the Lantana are used to make cheap furniture i.e. chair, easy chair, table, rack and other fancy articles. The sticks of Lantana are durable and resistant against insects and pests. For making cheap furniture from the plant, its sticks are cut. Spines are removed with the help of a sharpener. Different categories of sticks are used in making different articles. A few specific tools have been designed for the purpose.
With the observation that Lantana leaves are aromatic, the possibility of preparing incense material explored. The main emphasis has been given on:
Incense sticks are fragrant material used on various occasions. Bamboo sticks are pasted with the homogeneous material prepared from Lantana leaves and other ingredients. There are various assets needed for the preparation of incense sticks, such as high power grinder or fine powder and other essential material like plant gum and burning materials. Dry leaves of Lantana, its char are crushed in a locally available grinding device ( Jandhara) available in the village.
Cakes are also used as incense materials in temples and by community on the special holy occasions. The homogenous materials prepared from Lantana leaves and other ingredients are rolled manually and packed. High powder grinder is needed to obtain the fine power. The different ingredients are mixed together in a definite proportion and a base oil as adhesive is used.
Lantana leaves have a definite aroma on burning that can repel mosquitoes. This quality of the plant has been exploited for preparing mosquito repellent cakes from its leaves.
Lantana has also been respected for its property to attract bees. The bee species, particularly A. florae make its nest in Lantana. The idea has been crystallized and low cost beehive was made from Lantana to replace high cost beehive boxes. The high costs of the boxes prevent rural community from taking up beekeeping. This was realized that beekeeping can be one of the major household activities of rural communities. If low cost beehives made up of local material are introduced. The Lantana hive has proved to be cost effective.
The Lantana hive is a low cost technology useful for rural communities for beekeeping. It is a simple box with brood and super chambers.
The mechanical properties of Lantana have been utilized for making utility items. In rural areas, in the wake of poor purchasing power, the rural community makes domestic items out of the wood available around. Bamboo has been the major wood used in the past. Since Lantana has woody properties it can also be used to make such domestic articles. Grain storage, water storage baskets can be made from Lantana.
Energy is the prime need of the hilly region particularly when conventional sources of energy i.e. wood, kerosene oil and coal are costly and wood is the most important among the above. However, the forests are degraded and in such circumstances other sources have to be not only tapped, but have to be subjected to better use.
Lantana has been utilized as fuel in some parts of the hilly areas where forests are depleted. The high calorific value of the plant has proved it to be an excellent fuel. In this endeavor Briquetting and Gasification of Biomass can be two significant options.
Due to higher specific heat than that of wood, charcoal has replaced it in most of the developing countries, this will not only provide fuel for domestic use but also provide an income generating programme for the person who is unemployed.
Pyrolysis is a process in which biomass is charred for partial removal of volatiles. The pyrolysis temperature range between 250- 500*C. The process once started will continue automatically and get charcoal at approximately 500*C. The following table shows the effect of carbonization on charcoal recovery.
|% of fixed
|% of volatile
Line Diagram Of The Themochemical Biomass Conversion Process
Calorific Values Of Common Hilly Biomass
||Wood K. cal/kg
Lantana camara (Kurri)
Preparation of Charcoal Briquettes
The principle of briquetting consists of applying pressure to small pieces of char particles with or without a binder and converting them into a compact form. These briquttes could be in solid shape or in the form of a hollow cylinder. Binders are substances, which are used to bind the particles. They are molasses, starch, clay, resin & lime etc. The qualities of a good binder are its good binding ability, low cost, good smell while burning, readily available etc.
The charcoal obtained after the process of pyrolysis is first crushed into fine powder with the help of a wooden/metallic roller. After fine grinding, the binder like molasses of about 7 to 10% clay is also mixed to increase the agglomerating quality of the mixture. This mixture is stirred well to make a homogenous mixture.
Parthenium is another abundantly available weed in Himalayas. Adverse effects of Parthenium are not only found on human beings but also on animals. Parthenium contains sesquiterpene lactones which induce severe allergic reaction in susceptible individuals who are continuously exposed.
Mushroom cultivation requires no land and can be grown in the houses / small huts. Mushroom cultivation is taken up period of the year when generally the farmers have less field work, crops operation having short crop duration and no marketing problem. Thus crop is of a short cultivation and does not have marketing problem for its disposal. For mushroom cultivation Parthenium can be used as substrate.
Organic Farming has not only been useful in enriching soil but was has also been only effectively proven to be holistic approach to environment. Parthenium leaves and plant can be used for organic compost making.
Eupatorium is another weed spreading in Himalayan region as an alarming rate. Leaves of this plant are also used in homeopathy treatment. Eupatorium is a perennial shrub, grows rapidly, produces many shoots and branches and forms dense shade thus choking out desirable natural vegetations of prime value to livestock. Due to profuse seed production as well as propagation from stem this plant becomes wide spread. .Few experiments are also carried by HESCO to utilize this plant.
Composting: Eupatorium leaves and plant can be used for organic compost making.
Mosquito Repellent Incense Sticks and Candles:- Leaves of this plant are also used for candle and incense sticks making. Communities are sourcing this plant for commercial use as an income generating activity.