In this article we will discuss about:- 1. Introduction to Culm Production in Bamboo 2. Materials and Method of Culm Production in Bamboo 3. Site Preparation and After Care 4. Results and Discussion 5. Economic Analysis.
Contents:
- Introduction to Culm Production in Bamboo
- Materials and Method of Culm Production in Bamboo
- Site Preparation and After Care of Culm Production in Bamboo
- Results and Discussion Related to Culm Production in Bamboo
- Economic Analysis of Culm Production in Bamboo
1. Introduction to Culm Production in Bamboo:
Several factors have contributed for the dwindling of Medri bamboo (Dendrocalamus strictus) resource from the natural forests. To meet the growing demand by both paper industry and domestic purposes, there is a need for its commercial exploitation. Hence, plantations have been raised at two places, one at Dandeli and the other at Barchi of Haliyal Forest Division of Karnataka.
The rhizomes nurtured in nursery beds were uprooted and transplanted with adequate irrigation and proper input application. The culm production, girth and height of culms produced in every year have been studied.
The culm production increased with year and commercial size culms could be harvested after 5th year or 6th year. Dandeli range seems to be better suited for culm production than Barchi. The economic analysis has revealed that the annual income would be around Rs. 35,000 against the total cost incurred of Rs. 6,000, resulting in huge profits which gives the hope for its exploitation as a commercial crop.
Owing to the rare physical properties of elasticity, flexibility, resistance nature to impacts etc., bamboo forms an important essential forest commodity. Though 75% of Karnataka population utilize bamboo directly or indirectly, rural population is extensively dependent on this for various domestic purposes viz., agricultural implements, contrivance to transport and to store the produce, to build houses, as vegetable and even as fodder.
It also supports various cottage industries as raw material like agarbathi and Sericulture artisans on which nearly 3 to 4 million people are entirely dependent.
Bambusa arundinaceae and Dendrocalamus strictus are the species of bamboo which are found abundantly in the forests of Karnataka. Among these two species, the latter is confined to the drier areas of hilly tracks and the former is found in moist areas localising in hill slopes and valleys. Oclandra sp. and Oxytenanthera mono-stigma are the other species of bamboo found sporadically in evergreen and semi-evergreen belts of Western Ghats. Oxytenanthera stocksii is being cultivated in coastal belts of Karnataka.
Dendrocalamus strictus (locally known as Medri bamboo) forms an important under-story in dry deciduous and scrubby forests found intermixed with Bambusa or in pure patches in hilly slopes. Because of inadequate management, free and over grazing and unscientific exploitation by paper industry, the availability of this resource has been decreased. Several other factors are also contributed strongly for the dwindling of this resource from the natural stand.
They include loss of large areas of forest to hydro-electric projects, rehabilitation of displaced persons, release of land for cultivation, unauthorised cultivation and encroachment of forest lands, over grazing by domestic animals, frequent forest fires and other biotic pressures.
In recent years replacement of grass by Eupatorium giginoides, an obnoxious weed on the forest floor has decreased the establishment of bamboo seedlings. Man-made forest fires by gowlies and public owing to the conventional feeling of getting new sprouts of grass with early monsoon showers, Medri bamboo has disappeared from large tracks of forests or the surviving clumps are all mal-formed due to unscientific exploitation of younger culms in the periphery of the clump, hence, culms in the core are congested and lost the natural vigour.
The establishment of new seedlings from the fresh fluff after gregarious flowering by bamboo clumps during 1960 to 1968 has been hampered due to sudden opening of the canopy and the invasion of Eupatorium weed, forest fires and also by over grazing. Though, efforts were made to establish by planting the seedlings, the efforts went in vain as erected fences were forcibly removed and grazed by local cattle.
All these factors have decreased this resource in these forests resulting in acute shortage of bamboo raw material for paper industry and for other domestic purposes. The extraction cost of Medri bamboo has increased in recent years due to their scattered nature and sparse availability.
It is not wise legally to permit frequent invasions by public to the natural forests for extraction. Increased demand for Medri bamboo by both domestic and industry, coupled with depletion of this resource from natural forests have led to the need for commercial cultivation with shorter rotation periods. Hence, to increase production, plantations of Medri bamboo under intensive management with adequate irrigation and proper inputs were taken, up.
2. Materials and Method of Culm Production in Bamboo:
(a) Plantation Site:
Haliyal Forest Division extending over an area of about 1,50,000 ha which is also the home land of both Bambusa and Dendrocalamus was selected as plantation site. In 1984 plantation of D. strictus were raised at two places one at Dandeli and the other at Barchi under irrigation. The sites have undulating terrain with moderate slope and possess mostly sandy loam and clay loam soil.
The water holding capacity will decrease gradually and stabilise at 15% in pre- and post- monsoon periods. The plantations have been raised in open areas or in less shaded areas of dry moist deciduous forests adjoining to the perennial water source. The area under plantations varied from 4 to 7 ha depending on the feasibility. The culm production and growth pattern in these plantations are being studied.
(b) Nursery
The rhizomes with sprouted shoots of D. strictus were maintained in nursery beds before they were uprooted and transplanted with sufficient soil around the rhizomes. In 1985, 3 year old seedlings raised in nursery beds were used, while in 1986, one year old seedlings were transplanted in bigger polythene bags (20 x 30 cms) and maintained in the nursery for about a year were used.
In 1987, at Barchi, 3 year old seedlings with full shoots were used and at Dandeli 2 year old seedlings which were uprooted and transplanted in polythene bags (60 x 30 cms) and maintained for 8 to 10 months were used. On an average about 15 to 20% casualties occurred by the damages caused to the rhizomes during uprooting, handling and transportation.
3. Site Preparation and After Care of Culm Production in Bamboo:
Before planting, the selected sites were cleared of Eupatorium weed and then pits of 0.80 x 0.65 m were dug with spacing of 4 x 4 m or 5 x 5 m between rows and within row. The planting was completed by the end of March every year.
The plantations were well protected by barbed wire fencing. Cultural operations were attended regularly like scraping of grass or earthing up with proper bunding and loosening the soil. For each pit, 50 g of DAP + 250 g of Mussoriphos were applied every year. Irrigation was monitored with about 50 litres of water per clump provided twice a week from November to May.
In order to prevent the damage caused by wild boars and rats in the first year, 200 g of powdered neem cake was applied around the seedlings. No effective measures were taken to reduce the damage especially by monkeys and bisons in the interior parts of plantation.
Data on culm production and growth characteristics were collected by considering a representative plot comprising of 30 clumps in each year from 1985 to 1987 in two localities, the absolute number of culms produced per clump in each year were counted. GBH (Girth, Breast, and Height) for a culm which was randomly selected in each clump in each year were recorded. The average number of culms produced, girth and heights were computed.
4. Results and Discussion of Culm Production in Bamboo:
The culm production increased from year to year after planting. The average culm number/ha was higher at Dandeli range than at Barchi for 1985 planting.
It is more likely that culm production is not only dependent on the year, but also dependent on the age of the seedlings and spacing followed. For instance, at Dandeli 4 x 4 m spacing had enhanced culm production than 5 x 5 m
It is also more likely that the response of seedlings which are nurtured in polythene bags after uprooting was good with higher culm production than the seedlings which are transplanted directly to the field. Dandeli range is seems to be better suited area for bamboo cultivation compared to Barchi. It could be seen that both the average number of culms/clump and culms/ha were higher over years at Dandeli. Even the year average at Dandeli was higher for culm production.
The girth and height of culms increased with advancement in the year and plateauing after fourth year indicated that the culm can be harvested after 5th year for domestic purposes. It is also likely that the girth and height of Culm produced are directly dependent on the volume of the rhizome used at the time of planting. The commercial size culms can be harvested after 5th or 6thyear after allowing for 2 years of hardening. Better quality culms could be obtained by planting better quality rhizomes.
Ecology of Bamboo:
Ecologically Bamboo has four distinct stages.
They are:
(1) Development of rhizomes during summer,
(2) Sprouting of new shoots during spring,
(3) Growth of sprouted shoots during autumn and
(4) Dormant stage during winter.
For better sprouting and growth of shoots, it needs minimum mean temperature of 14oC. Unfortunately peak growing season and peak monsoon season coincides resulting in 20 to 30% of-casualties of sprouted shoots by fungal infection in the areas where drainage is poor. Thus, only few culms survive and sprout during pre- and post- monsoon periods. Bamboo prefers sandy soils with loam and clay contents in equal proportions.
Both rhizome formation and culm production are directly dependent on the moisture content of the soil. Optimum irrigation plays a key role in culm production in both post- and pre-monsoon periods. Owing to the positive relationship between rhizome formation and culm production, for better sprouts of shoots, bamboo requires a minimum of 20% of soil moisture. Alternations of any of these abiotic factors will considerably hamper the survival of culms (to 10 to 30%).
Both phosphorous and nitrogen are essential nutrients required for bamboo growth. The later help in sprouting and growth of shoots and the former helps in rhizome formation. Inadequate availability of these nutrients in lateritic soils due to leaching of nitrogen by heavy rains and permanent bonding of phosphorous by aluminium and iron will decrease the growth of bamboo. Artificial supply of these nutrients through inputs will help in enhancing the growth of bamboo. Silica is needed for hardening of the culms.
The root system of bamboo is very unique comparing to other monocots. The roots are distributed closely and heavily around the clump base resulting in fast exhaustion of nutrients around the clump. Either by mulching of its own biomass or encouraging natural mycorrhizae and microbes will help in renewal of required nutrients regularly. Artificial application of fertilisers coupled with controlled irrigation during lean periods play a crucial role in boosting the bamboo growth.
5. Economic Analysis of Culm Production in Bamboo:
(a) Expenditure:
The cost incurred for raising one ha of plantation and maintaining the same for five years is estimated to be Rs. 30,000. Considering the flowering cycle once in 30 to 40 years, bamboo can be conveniently harvested for a minimum of 25 years. The cost expended on the maintenance of plantations from 6th year to 30th year (i.e. total of 25 years) will come to about Rs. 1,17,500. The pooled cost expended for 30 years will be around Rs.1,47,500.
(b) Income:
From the data it is evident that on an average 10 culms per clump would be available for harvesting annually. Thus with total population density of 625 per ha following 4 x 4 m spacing will yield 6250 culm per ha annually. The annual income incurred by 5,000 culm will be Rs. 35,000 per ha with selling value of Rs. 7 per culm making allowance for damages of about 20%. Thus the total income accrued for 30 years would be Rs. 8,75,000. By incurring expenditure of Rs. 30,000 per ha till 6th year, the annual net-income would be Rs. 35,000 per ha which can be extended till the clumps flower.
Conclusion:
Medri bamboo though has tremendous potentiality for commercial cultivation, it has not been exploited. Several factors have contributed for its depletion from natural stand. Increased demand for Medri bamboo has led to the need for its cultivation with shorter rotation period. Hence plantations of Medri bamboo were raised with spacing of 4 x 4 m or 5 x 5 m at two places one at Dandeli and the other at Barchi of Haliyal Forest Division of Karnataka.
The experimental results indicated that D. strictus respond well to the irrigation and input application. The average culm numbers per clump and per ha were higher at Dandeli range than at Barchi. The culm production was seems to be dependent on the age and spacing followed. For instance, at Dandeli 4 x 4 m spacing had enhanced culm production than 5 x 5 m at Barchi following same spacing differential culm productive was evident.
The performance of seedlings which were nurtured in polythene bags before transplanting was superior than those which were transplanted directly to the field. Dandeli range is seems to be the better suited area compared to Barchi because both average culms/clump and culms/ha were higher over years at Dandeli. From the analysis it could be seen that commercial size culms can be harvested after 5th or 6th year.
Economic analysis indicated that the cost incurred for raising and maintaining one ha. of plantation for 30 years would be around 1,50,000. The income accrued by harvesting on an average 5,000 culm per ha and selling at Rs.7 per culm will be Rs. 35,000 can be easily obtained.
The analysis further gives a hope for its commercial exploitation. More scientific and systematic approach would be to explore the high genetic variability existing by selection of clumps with higher culm productivity. In recent years, a strain (Vpb-I) of phosphobacteria, a micro-organism has been known to enhance the yield in acid soils by decomposing the organic matter resulting in production of organic acids which solublise the bounded phosphates and make it available to the plant.
Hence, it would be interesting to probe the effect of the phospho-bacteria on the culm production of bamboo after artificial inoculation. It is also essential to understand both biotic and abiotic factors which are playing significant role in enhancing the culm productivity.