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J. Bamboo and Rattan, Vol. 4, No. 1, pp. 1 2 (2005) VSP 2005.

Foreword

Dear Reader, This issue is already the rst of our fourth volume. We managed to complete three volumes, each of them with 400 pages or more, with many interesting articles. While reecting about this Foreword, I browsed the pages of some past issues and really I am satised by the scientic level. Our authors did a good job! The same goes for the members of our Editorial Board, whose names appear on the inside front cover. Fortunately we also have the support of many external reviewers. In 2004 the people listed below have been so kind to act as such: J. van Acker, B. Baker, V. Brias, K. Cheung, J. Dawson, Y. Fracheboud, D. Goh, Y. Inagaki, P. Jaehrlich, W. de Jong, A. Jorissen, S. Kawai, A. Kempthorne, W. Killmann, Hoi Why Kong, M. T. Lim, J. Loferski, A. Loo, P. Mathew, C. Miles, T. Okamoto, A. A. OtengAmoako (twice), S. Pagiola, D. Pearce, N. K. Rao, T. Sunderland, H. Thoemen, L. Wgberg and L. Weisner. Overlooking this long list I remember very well the huge support which has been given by all these people, resulting in a high quality of the articles published. I would like to express my sincere gratitude for their time and effort. They do their reviewing in their own time as volunteers, without any reward. The aim of our Journal is to provide a platform for scientic publications on bamboo and rattan, but in fact our aim is to alleviate poverty in developing countries where bamboo and rattan are indigenous. On some occasions in my life I have been in a position to assist in housing projects in direct contact with the local population. Still I have a good feeling about such activities; I will never forget the progress in happiness for the families and the improvement in childrens diseases. Are such things valid for our Journal? Not in the short term, but in the long term I am convinced our scientic articles will support improvements for poor families. Scientic research is a must for the future of any activity. For this reason I am happy to have the honour to act as Editor-in-Chief.

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Foreword

I do hope this rst issue of our fourth volume is the next step towards a promising future. Together we will manage to continue on our way. Only one thing I would like to see: letters to the editor! In other journal these make the journal more lively. Reactions by readers and answers by authors would be quite an improvement. Please think about this? I do hope you will enjoy this volume even more as the previous ones. JULES JANSSEN Eindhoven, November 23, 2004



Optimum conditions for testing germination of bamboo seedsM. M. S. RAWATSeed Laboratory, Silviculture Division, Arid Forest Research Institute, New Pali Road, Jodhpur, Rajasthan, India

Editorial note: Unfortunately the author of this article passed away before he could use the recommendations by the reviewers for his revised article. To pay respect to this scientist and in view of the importance of the information in this article, it is published with editing only. On the next page you will nd an Obituary, followed by the article. JULES JANSSEN

Dr. Man Mohan Singh Rawat

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M. M. S. RAWAT

Obituary Dr. Man Mohan Singh Rawat (31 December 19561 March 2004) It is with a deep sense of grief to learn of the sudden passing away of Dr. M. M. S. Rawat after coronary artery heart by-pass surgery at the young age of 47 years. This came as a great shock. Born in 1956 at Dehra Dun (Uttaranchal), India, he joined the Forest Research Institute, Dehra Dun in 1977 as Research Assistant after his MSc in botany in 1976 from H. N. B. Garhwal University. He was awarded the DPh degree in Forestry Seeds in 2001 from FRI Deemed University, Dehra Dun. In 1996 he was appointed as Research Ofcer at Forestry Seeds Laboratory, Forest Research Institute, Dehra Dun. He had very good and vast research experience in forestry seeds research. He was appointed as Scientist-B and joined the Arid Forest Research Institute, Jodhpur (Rajasthan) on 13 June 2002. He has about 30 research papers published in various national and international repute journals to his name. He was working on the seeds quality and their improvement for arid zone forestry in India from June 2002 and felt ill in the last week of November 2003 after diagnosis of coronary artery heart disease. In December 2003 he went to New Delhi for bypass surgery. While recovering his health at Dehra Dun he passed away on 1 March 2004 after sudden heart failure. Dr. M. M. S. Rawat was a person of quiet disposition, hard working, amiable and helpful for staff, colleagues and friends. His wife, Mrs. Neelam Rawat, a teacher at St. Thomas College, Dehra Dun, was a source of great strength to him. His wife Mrs. Neelam Rawat and only daughter, Miss Vanushri Rawat, who is doing her study for a bachelor degree in engineering at Dehra Dun, survive him. Dr. M. M. S. Rawat will be a great loss to the science community as a whole and especially in forestry seeds in India. He will be also greatly missed by his relatives, friends and colleagues. May his soul rest in peace.

Optimum conditions for testing germination of bamboo seeds

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AbstractStudies were conducted on seeds of three bamboo species, viz., Dendrocalamus membranaceus, D. strictus and Bambusa nutans, to determine a combination of conditions ensuring the most regular, rapid and complete germination under laboratory conditions. The seeds were sown at different combinations of incubation temperatures (20, 25, 30, 35, 40 C and 2030 C) and sowing media (top of paper, between paper and sand). Seeds were also sown in the presence and absence of light at 30 C on top of paper. The ideal conditions for testing seeds of all the three species were found to be 30 C, top of paper and preferably presence of light. Key words: Dendrocalamus membranaceus; D. strictus; Bambusa nutans; seed; germination.

INTRODUCTION

It is indispensable to follow a standard pattern for testing seeds for germination in order to ensure uniformity and reproducibility of results. Testing under eld conditions is normally unsatisfactory and, therefore, laboratory methods have been developed in which the external conditions are controlled to obtain most regular, rapid and complete germination of seeds [1]. The most important factors affecting germination under laboratory conditions are temperature, media and light, which need standardisation for each species. Temperature is one of the most critical factors and there is usually an optimal temperature below and above which germination is delayed or prevented. Soil is rarely used as a substrate for germination tests because each sample will vary greatly in physical, chemical and biological properties. Thus, the lack of reproducibility and difculty in comparing tests of different seed lots renders it unsuitable. Articial media are much more easily standardized and, hence, the International Seed Testing Association (ISTA) [2] recognized three germination media: top of paper (TP), between two layers of paper (BP) and sand. The effect of light on germination has been known to vary considerably with the seeds of different species. Some seeds germinate after being given a brief illumination while some are indifferent to the presence or absence of light during germination. Such standardizations have been lacking for bamboo species probably due to rare availability of seeds. ISTA rules [1], though providing guidelines for testing few tropical tree species, do not mention bamboo species. The seeds of most bamboos have been reported to lose viability rapidly under ordinary storage conditions [3] and, therefore, require testing before sowing in nursery. The present paper reports optimum germination conditions for the seeds of three bamboo species, viz., Dendrocalamus membranaceus, D. strictus and Bambusa nutans, to obtain full germination potential of a seed lot.

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M. M. S. RAWAT

MATERIALS AND METHODS

Seed The seeds of D. membranaceus and D. strictus were collected from the campus of Forest Research Institute, Dehra Dun (Uttranchal, India) during 1992 and 1994, respectively, while the seeds of B. nutans were procured from Tropical Forest Research Institute, Jabalpur, MP. The seeds were collected during April from Sarguja area of MP where it owered gregariously during 1994. The seeds stored at 5 C with around 5% moisture content were used for the following study, except in second experiment where seeds of D. strictus stored at 15 C were used. Germination test Constant temperatures of 20, 25, 30, 35, 40 C and alternating 2030 C (16 h at 20 C and 8 h at 30 C) were used in combination with germination media TP, BP and sand. All the tests were carried out in four replications of 100 seeds each. Glass petridishes of 15 cm diameter lined with moist towel germination paper were used as TP. For BP, seeds were spread on moistened germination paper and rolled. Sterilized quartz sand as prescribed in ISTA rules, lled in enamelled trays, 4530 cm in size, was used as a medium in which seeds were sown 1 cm deep. All the media were kept just moist throughout the test period using tap water. All the seeds sown as above were incubated in seed germinators set at specied temperatures with around 95% humidity. Light was provided for 8 h daily during the test period by cool uorescent lights. Germination was recorded daily and a seed was counted as germinated when radicle and plumule attained at least 1 cm length and were free from visual fungal infection or deformation. In sand, a seed was considered as germinated when plumule attained at least 1 cm height above the sand surface. The test was terminated when there was no further germination. In the second experiment, the effect of light on germination was observed at 30 C on TP following the results of the above experiment. The germinators set at 30 C with and without light were used to investigate the effect of light. Care was taken to avoid light during recording of germination. The mean germination time (MGT) was calculated as described by Bonner [4]. Treatments effect and interaction was analysed by ANOVA techniques after arc sin transformation of germination percentages.

RESULTS

The seeds of all the three species were found to be non-dormant and germinated readily within few days. The germination, in terms of percent as well as MGT was, however, signicantly (P < 0.01) affected by incubation temperature, sowing media and their interaction as detailed below.


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Effect of temperature on germination per cent In D. membranaceus (Table 1), signicant difference was observed in mean germination per cent at all the temperatures tested (P < 0.05), except between 35 C and 2030 C, with 41.0 and 37.7%, respectively. The maximum mean germination of 46.2% was obtained at 30 C, while the minimum was recorded at 20 C (9.8%). In D. strictus (Table 2), the mean germination per cent at 30 and 25 C was maximum (84.3 and 82.6%, respectively) and signicantly higher as compared to other temperatures (P < 0.05). This was closely followed by 35, 40 and 2030 C with 78.3, 77.3 and 76.9% mean germination, respectively, and remained at par with one another. At 20 C the mean germination was reduced to 58.7%. In B. nutans (Table 3), at 30 and 35 C the mean germination was 54.6 and 57.6%, respectively, and was signicantly higher (P < 0.05) than the rest of the temperatures. At 25, 2030 and 40 C the mean germination ranged betweenTable 1. Effect of temperature and media on percent germination of D. membranaceus seeds Temperature ( C) 20 25 30 35 40 2030 Mean Media TP 15.5 (23.2) 50.0 (45.0) 59.5 (50.5) 57.0 (49.0) 34.0 (35.6) 50.3 (45.2) 44.4 (41.4) BP 14.0 (22.0) 49.0 (44.4) 60.0 (50.8) 50.0 (45.0) 30.0 (33.2) 41.8 (40.3) 40.8 (39.3) Sand 0.0 (00.0) 10.0 (18.4) 19.0 (25.9) 16.0 (16.4) 12.3 (20.5) 21.0 (27.3) 13.0 (19.3) 9.8 (15.0) 36.3 (36.0) 46.2 (42.4) 41.0 (39.2) 25.4 (29.8) 37.7 (37.6) Mean

Values in parentheses are arcsin transformed. temperaturemedia 2.70.

CD at 5%: temperature 1.56; media 1.10;

Table 2. Effect of temperature and media on percent germination of D. strictus seeds Temperature ( C) 20 25 30 35 40 2030 Mean Media TP 69.5 (56.5) 87.5 (69.9) 87.5 (69.4) 85.5 (67.7) 86.5 (68.5) 82.3 (65.2) 83.1 (66.2) BP 71.5 (57.8) 83.0 (66.0) 86.5 (68.7) 86.0 (68.1) 84.5 (67.1) 78.3 (62.3) 81.6 (65.0) Sand 35.0 (36.3) 77.3 (61.5) 78.8 (62.8) 63.5 (52.9) 61.0 (51.4) 70.3 (57.0) 64.3 (53.7) 58.7 (50.2) 82.6 (65.8) 84.3 (66.0) 78.3 (62.9) 77.3 (62.3) 76.9 (61.5) Mean



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M. M. S. RAWAT

Table 3. Effect of temperature and media on percent germination of B. nutans seeds Temperature ( C) 20 25 30 35 40 2030 Mean Media TP 33.5 (35.4) 54.5 (47.6) 60.5 (51.1) 61.0 (51.4) 53.5 (47.3) 52.8 (46.6) 51.0 (45.6) BP 39.0 (38.6) 52.0 (46.2) 57.5 (49.3) 61.0 (51.4) 55.0 (47.9) 47.8 (43.7) 52.0 (46.2) Sand 8.5 (16.9) 31.0 (33.8) 45.8 (42.6) 50.8 (45.5) 31.8 (34.3) 29.5 (32.9) 32.9 (34.3) 27.0 (30.3) 45.8 (42.5) 54.6 (47.7) 57.6 (49.4) 43.4 (41.2) 43.3 (41.1) Mean



45.8 and 43.3%, and remained at par with one another, while the minimum mean germination was recorded at 20 C (27.0%). Effect of media on percent germination In D. membranaceus (Table 1), TP gave maximum mean germination of 44.4% and was signicantly different from other media (P < 0.05). BP followed this with 40.8% and the minimum 13.0% was recorded in sand. In D. strictus (Table 2), the mean germination of 83.1 and 81.6% was recorded on TP and in BP, respectively, and remained at par with each other. In sand, the mean germination was signicantly reduced to 64.3%. Similarly, B. nutans (Table 3) showed signicantly higher mean germination on TP (51%) and BP (52%) as compared to sand (32.9%). Effect of temperature on mean germination time In D. membranaceus (Table 4), the mean MGT was signicantly different at all the temperatures (P < 0.05). The minimum was recorded at 30 C (15.32), while the maximum of 21.61 was recorded at 20 C. In D. strictus (Table 5), at 30 and 35 C the mean MGT was minimum (9.82 and 9.65, respectively) and at par with each other but signicantly different from other temperatures (P < 0.05). The mean MGT was highest at 20 C (18.63). In B. nutans (Table 6), all the temperatures showed signicant difference (P < 0.05) in mean MGT, except at 25 and 2030 C, which were at par with each other with 16.60 and 16.80, respectively. At 35 C the mean MGT was lowest (13.27) followed by 30 C (14.16), while the maximum was obtained at 20 C (20.76). Effect of media on mean germination time In D. membranaceus (Table 4), signicantly lowest mean MGT (16.27) was obtained in TP (P < 0.05), closely followed by BP (17.48) while maximum of

Optimum conditions for testing germination of bamboo seeds Table 4. Effect of temperature and media on mean germination time (MGT) of D. membranaceus seeds Temperature ( C) 20 25 30 35 40 2030 Mean Media TP 21.38 16.52 13.02 13.32 17.53 15.87 16.27 BP 21.45 17.07 13.22 16.10 19.57 17.48 17.48 Sand 22.00 21.61 20.33 20.55 21.05 20.50 21.00

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Mean

21.61 18.40 15.52 16.66 19.38 17.95

CD at 5%: temperature 0.32; media 0.22; temperaturemedia 0.55. Table 5. Effect of temperature and media on mean germination time (MGT) of D. strictus seeds Temperature ( C) 20 25 30 35 40 2030 Mean Media TP 17.14 9.82 7.44 7.48 8.01 9.87 9.96 BP 18.08 8.93 7.74 7.50 8.04 9.63 9.99 Sand 20.69 14.52 13.79 14.47 14.12 14.87 15.41 18.63 11.09 9.65 9.82 10.05 11.46 Mean

CD at 5%: temperature 0.44; media 0.31; temperaturemedia 0.75.

21.00 in sand. In D. strictus (Table 5), the lowest mean MGT, i.e., 9.96 and 9.99, was obtained at TP and BP, respectively, which remained at par, while the maximum was obtained in sand (15.41). A similar trend was observed in B. nutans (Table 6), where TP and BP showed minimum MGT of 14.80 and 14.69, respectively, as compared to sand (19.09). Effect of light/dark on percent germination and MGT In all the three species there was insignicant difference (P > 0.05) in percent germination of seeds sown under light and dark (data not shown). The germination was 57.0 and 56.0% in D. membranaceus, 61.5 and 64.0% in D. strictus and 55.0 and 54.5% in B. nutans in light and dark, respectively. Similarly, MGT was not signicantly affected by the presence or absence of light in all the three species. The MGT was 10.97 and 11.18 in D. membranaceus, 9.15 and 9.00 in D. strictus and 10.17 and 10.30 in B. nutans in light and dark, respectively.

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M. M. S. RAWAT

Table 6. Effect of temperature and media on mean germination time (MGT) of B. nutans seeds Temperature ( C) 20 25 30 35 40 2030 Mean Media TP 20.09 14.69 12.24 11.85 15.28 14.68 14.80 BP 20.53 14.58 12.73 11.85 13.33 15.13 14.69 Sand 21.66 20.55 17.53 16.12 18.14 20.59 19.09 20.76 16.60 14.16 13.27 15.58 16.80 Mean

CD at 5%: temperature 0.39; media 0.27; temperaturemedia 0.67.

DISCUSSION

The germination characteristics of seeds of bamboo species seem to be specic to a particular kind. All the three species under investigation exhibited more or less similar response with respect to incubation temperature, sowing media and presence or absence of light. Temperature is one of the most critical factors in the laboratory germination of seeds. This became evident in all the three species of bamboos, which showed 30 C as the ideal temperature for germination, though seeds of D. strictus and B. nutans germinated equally well at 25 and 35 C, respectively. As expected, it took minimum days to complete germination at 30 C as the MGT was minimum at this temperature, except B. nutans, which showed minimum at 35 C. At temperatures below or above 30 C, the germination was not only drastically delayed but also reduced in percentage with little exceptions. A critical temperature of 30 C has been shown to be ideal for several indigenous tropical tree species [5, 6]. Maximum germination at 30 C has also been reported in D. strictus [7] and B. tulda [8]. With respect to germination media, all three species of bamboos germinated equally well on TP and BP, except D. strictus, which performed best at TP. TP, however, was found to be the best as on this media seedlings could be evaluated more easily for abnormalities. Seedlings in BP remained somewhat whitish yellow due to lack of sufcient light, making it difcult to distinguish albino seedlings, which seems to be a characteristic of bamboo species. TP has been reported as a best media for germination of B. tulda seeds [8]. ISTA [2] also prescribed TP as the best media for germination of small seeds. In sand the germination was not only drastically slow but also reduced signicantly. The seeds of all the three species germinated equally well in dark and light. There was no signicant difference in germination percent, as well as MGT in seeds sown in total darkness and in light (P > 0.05). However, a cycle of 8 h daily light seems to be essential for proper evaluation of seedlings for abnormality. Seedlings in dark remained whitish yellow making it again difcult to distinguish albino seedlings.


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ISTA [2] also mentioned that seedlings grown in complete dark are etiolated and become more sensitive to attack by micro-organisms and it becomes difcult to detect chlorophyll deciency. Thus, the ideal conditions that could be used for determining germination capacity of a seed lot are 30 C, TP and preferably presence of light. Although the above study is based on a single seed lot of each species, it provides a base regarding testing conditions of bamboo seeds. The availability of different seed lots of a species of bamboo is a major constraint mainly due to long owering intervals of several years.

REFERENCES1. ISTA, International Rules for Seed Testing, Seed Science and Technology 24 (Suppl.) (1996). 2. ISTA, International Rules for Seed testing. Rules and annexes. International Seed Testing Association, Seed Science and Technology 4, 3117 (1976). 3. M. M. S. Rawat and R. C. Thapliyal, Storage behaviour of bamboo (Dendrocalamus membranaceus) seeds, Seed Science and Technology 31 (2), 397403 (2003). 4. F. T. Bonner, Germination responses of loblolly pine to temperature differentials on a two way thermogradient plate, Journal of Seed Technology 8 (1), 614 (1983). 5. B. N. Gupta, P. G. Pattanath, A. Kumar, R. C. Thapliyal and A. S. Raturi, Rules for germination test of tree seeds for certication, Indian Forestry 101 (6), 320327 (1975). 6. B. N. Gupta and P. G. Pattanath, Germination responses of some forest tree seeds under controlled conditions, Indian Forestry 102 (5), 264272 (1976). 7. B. N. Gupta and A. Kumar, Interrelated effects of temperature and moisture on seed germination of Dendrocalamus strictus Nees, Indian Forestry 103 (3), 212219 (1977). 8. R. C. Thapliyal, O. P. Sood and M. M. S. Rawat, Effect of moisture content and storage temperature on the viability of Bambusa tulda seed, International Tree and Crops Journal 7, 6795 (1991).



Commercial edible bamboo species of the North-Eastern Himalayan region, India. Part II: fermented, roasted and boiled bamboo shoots salesB. P. BHATT , L. B. SINGHA, M. S. SACHAN and K. SINGHAgroforestry Division, ICAR Research Complex for North Eastern Himalayan Region, Umroi Road, Umiam, Meghalaya 793 103, India

AbstractThe sales of fermented, roasted and boiled bamboo shoots in the market places of Arunachal Pradesh, Manipur, Meghalaya, Nagaland and Sikkim, of the North-Eastern Himalayan (NEH) region, India have been reported. The results are based on the survey of 118 markets covering 1200 primary and secondary vendors from 51 districts of NEH region. The consumption of fermented, roasted and boiled shoots was estimated to be ca. 680 tonnes; the highest occurs in Arunachal Pradesh (481 tonnes/year) and the lowest in Nagaland (19.5 tonnes/year). The bamboo shoots are consumed in the form of fermented-slice, crushed-fermented moist, crushed-fermented dry, fermented whole shoot, roasted whole shoot and boiled whole shoot in different states of the region. Costreturn analysis for sales of these bamboo products revealed a net income of 23 million rupees per annum (US$ 502 950) from the entire region with the highest (17.5 million rupees/year or US$ 38 270) in Arunachal Pradesh and the lowest in Sikkim (0.47 million rupees/year or US$ 10 280). Employment opportunities have also been worked out and ca. 1260 persons/year could earn their subsistence through selling of bamboo shoot products. Key words: Bamboo shoots; North-East Himalaya (NEH) region; India; consumption; costreturn analysis.

INTRODUCTION

Over 1500 bamboo species belonging to 75 genera occur worldwide in natural forests, semi-exploited stands and intensive plantations [1], of which India has contributed about 130 species belonging to 23 genera [2, 3]. As many as 78 bamboo species (both indigenous and exotic) belonging to 19 genera are being reported from the North-East region of India [4]. To

whom correspondence should be addressed. E-mail: [email protected]

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The range of application of bamboo for mankind is remarkable, with an annual use of 12 kg bamboo biomass per capita in Asia [5, 6]. Besides the use of different bamboo parts as fuel, fodder, medicine, pulping material, construction and household as well as farms, the edible nature of tender shoots of some species enhanced the importance of bamboo in the global scenario. Data on worldwide production of bamboo products are extremely unreliable, as they do not appear in the major commodity databases. Worldwide, more than 2 million tonnes of bamboo shoots are consumed annually [7] with approximately 1.3 million tonnes produced in China [8]. In metropolitan Tokyo, more than 8000 tonnes of young shoots are consumed annually [9]. In India, bamboo shoots in fresh, fermented, roasted and pickle form are consumed, especially in the North-East region. Around 1000 tonnes of fresh bamboo shoots are reported to be obtained only through market places of three tribal states of this region, where an annual gross income of ca. US$ 111 000 could be generated [10]. In spite of the consumption of fresh bamboo shoots in the North-East region, a considerable quantity of bamboo shoots is also consumed in the form of fermented products, roasted and pickles after processing through conventional methods. Almost all the ethnic groups of the region use bamboo shoot products in preparing major or minor food items. They are also applied in small quantities as food additives to improve delicacy of vegetarian or non-vegetarian dishes. Among the processed bamboo shoots, fermented products and pickles fetch higher income due to the ability of their long-term preservation with higher market price and their consumption throughout the year. In part I of this series, entitled Commercial edible bamboo species of the North-Eastern Himalayan (NEH) region, India: Young shoot sales [11], the main emphasis was on investigation and documentation the diversity of commercial edible bamboo species available in the NEH region, the annual consumption pattern of fresh tender shoots through market places and their costreturn analysis, including physical efforts made in merchandizing fresh bamboo shoots. Most of the Governmental and Non-Governmental Organisations are giving full emphasis to utilize the available bamboo resources in the region through scientic implications for the sustainable development of the NEH region, and India as well. Although, no such efforts are being made on edible nature of bamboo shoots and their allied products with commercial importance in the NEH region or elsewhere in other parts of India. In continuation to the previous study on edible bamboo species in the NEH region [11], the present study gives special emphasis to investigate and to document the annual consumption rate of processed bamboo shoot products through market places, their commercial values, the costreturn analysis, the indigenous technical knowledge (ITK) on bamboo shoot processing, etc. An attempt has also been made to understand the revenue generation through traditionally processed bamboo shoots and its potential to provide employment opportunities in the NEH region of India.

Commercial edible bamboo species of the North-Eastern Himalayan, Part II

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STUDY SITE

The study was carried out in the North-Eastern Himalayan region (NEH) of India, covering 7 states, namely Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura (Fig. 1). The region lies between 2130 N latitude and 8598 E longitude, and occupies an area of 18.4 million ha. The region has a difcult terrain with hilly topography, characterized by steep slopes, gorges and plateaus with less than 15% valleys. The elevation ranges from 100 m to 5600 m above sea level (asl), tropical to alpine agro-climatic condition with ca. 100 to 6000 mm annual rainfall. This peculiar agro-climatic condition of the NEH region has supported very rich and diverse ora and fauna including bamboo species for which the region could account a position among the 25 hot spots of the world. Based on the State of Forest Report [12] and Basic Statistics [13], the total land area and human population of the 7 states of the NEH region are shown in Fig. 2, in which the highest population density was reported in Tripura (304 persons/km2 ) and the lowest in Arunachal Pradesh (13 persons/km2 ). The range of total human population in the 7 states is very large and varies from 0.89 to 3.19 million. More

Figure 1. Location map of the study sites in the NEH region, India.

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B. P. Bhatt et al.

Figure 2. Total human population (1) and geographical area (!) of 7 states in the NEH region, India.

than 70% of the total population of the region belongs to the rural sectors and they exploit tender bamboo shoots from natural forests, plantation forests and home gardens for their income generation and livelihood.


A survey of fermented, roasted and boiled bamboo shoot products in market places of 7 selected states in the NEH region was carried out from March 2003 to March 2004 at four months interval. More than 40% of the available market places of the entire districts of the 7 states were randomly surveyed. Out of 297 market places a total of 118 market places belonging to 51 districts of the NEH region was surveyed. Vendors of bamboo shoot products were categorized as primary (those who process bamboo shoots for different products and sell) and secondary (those who purchase processed products at wholesale rate and sell in retail rates). Baseline information was gathered from 1200 primary and secondary vendors through suitable preprepared questionnaires. This information includes the number of primary and secondary vendors available in the market places, market days per week, quantity of fermented, roasted and boiled bamboo shoots sold per day, their availability period and costs (per kg), the number of persons involved including gender and age group, the physical efforts and nancial investments made in merchandizing (fermented, roasted and boiled bamboo shoots), etc. Information on indigenous technical knowledge for the processing of bamboo shoots and recipes of different


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tribal communities/ethnic groups were also accumulated from the nearby villages of the respective market places. All the data were statistically analysed and presented in this paper.

RESULTS

Product preparations and description In addition to the bamboo shoot pickles, 5 more bamboo shoot products, such as fermented slice, crushed-fermented moist, crushed-fermented dry, fermented whole shoot and roasted whole shoot, were recorded from the NEH region of India. All the 5 fermented and roasted bamboo shoot products were sold in the market places of Arunachal Pradesh (Figs 35) and Nagaland (Fig. 6), and were consumed by almost all the ethnic groups and tribal communities in the two states, except Monpas (Tibetans) of West Kameng and Tawang districts of Arunachal Pradesh. In Manipur fermented slice bamboo shoots and fermented whole shoots were observed in the market places, whereas only crushed-fermented (moist) was sold in Meghalaya. A unique boiled bamboo shoot product of two bamboo species was observed being sold in the market places of Sikkim. The consumption and commercialisation of processed bamboo shoots in Mizoram and Tripura were negligible. Only few ethnic groups in Mizoram consume fermented slice bamboo shoots, which in fact was met from their own processing and not through market places (Fig. 7).

Figure 3. Fermented whole shoot sold at Ganga market, Itanagar, Arunachal Pradesh.

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Figure 4. Roasted and crushed-fermented moist bamboo shoots sold at Seppa, East Kameng District, Arunachal Pradesh.

Figure 5. Fermented crushed bamboo shoots sold at Pasighat, East Siang District, Arunachal Pradesh.


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Figure 6. Sliced-bamboo shoots packed in polythene for fermentation process, Dimapur Ditrict, Nagaland.

Figure 7. Sliced-fermented bamboo shoot sold by secondary vendors at Khwairamband Bazar, Imphal West District, Manipur.

The principle of bamboo shoot fermentation in different states in the NEH region was similar although the indigenous technology for the processing of fermented bamboo shoot products is different among the 7 states, and even from one ethnic

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group to another. Generalized conventional methods used for the processing of fermented, roasted and boiled bamboo shoot products employed in NEH region are highlighted below. Fermented-slice. Freshly harvested bamboo shoots are cleaned and washed with water. They are thinly sliced and immediately packed with polythene sheets, and wrapped with cloth/synthetic sack. They are kept under pressure using heavy weights (boulders or concrete slabs etc.) for 36 months for fermentation. The fermented bamboo shoot slices can be preserved for several months after the completion of the fermentation process. Crushed-fermented moist. Fresh bamboo shoots are simply crushed using wooden mortar and pestle after removing the hairy sheaths, and packed in polythene bags or lled into plastic/glass bottles. After 23 months fermentation in anaerobic condition, it becomes ready to consume. Crushed-fermented dry. Fresh bamboo shoots are cleaned, washed and crushed into small pieces. They are allowed to get semi-fermented for 37 days in airtight pitcher or other containers, and then sun dried. After proper drying, they are packed in polythene bags and sold in the market places or are preserved in dry form for future use. Fermented whole shoot. Freshly harvested bamboo shoots are cleaned and washed with water. They are fermented as usual in anaerobic condition using heavy weights, as in the case of fermented slice bamboo shoots. Generally, it requires more time for complete fermentation than the other fermented products. Roasted whole shoot. Fresh bamboo shoots are re roasted together with the culm sheath/swathe. After proper roasting, the culm sheath is removed carefully. It may be consumed as usual, or consumed along with rice, bread etc. In the market places, it is sold after wrapping with banana leaf, turmeric leaf, etc. It can be preserved only for 23 days. Boiled whole shoot. Freshly harvested bamboo shoots are simply boiled in water in a large container until they are cooked properly. After draining off the water, they are ready for consumption. This bamboo shoot product is also sold as roasted whole shoot in the market places, wrapping with banana leaf, but it cannot be preserved for more than 23 days. In addition to the above bamboo shoot products, fermented bamboo shoots squash, a by-product of bamboo shoot fermentation, was observed to be consumed on a commercial scale in Nagaland state. During the preparation of crushed fermented bamboo shoot products, bamboo shoot juices were decant and allowed to ferment in air tight containers for six to ten days till it becomes ready for consumption.


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Figure 8. A customer purchasing bamboo shoot squash at Wokha market, Nagaland.

Liquid remnants of fermented-slice or crushed bamboo shoots after their complete fermentation were consumed as usual in little quantity as food additives. The annual consumption of bamboo shoot squash in Nagaland was recorded as ca. 71 630 litres per year (Fig. 8). Table 1 gives the traditional dishes prepared from fermented, roasted and boiled bamboo shoot products in NEH region. The consumption pattern of different bamboo shoot products are different among the different ethnic groups, although, all the fermented products are consumed as food additives by applying in little quantity to increase the delicacy of different dishes. In the Wokha district of Nagaland, consumption of the basal part of tender culm sheath after fermentation is also a unique bamboo shoot product of the region. It is known as Rhuyem by the Lotha tribe and especially used for the preparation of duck-meat curries. In Manipur, Soibum (slice fermented) and Soidon (whole shoot fermented) are the two highly esteemed fermented bamboo shoot products which are consumed as major dishes, as well as used as additives in vegetable and non-vegetable dishes. In Mizoram, Tripura and Sikkim, there were no fermented bamboo shoot products sold in the market places, whereas, in Sikkim, bamboo shoots in boiled form was observed to be sold on a commercial scale. The period of availability of fermented, roasted and boiled bamboo shoot products in the market place of the NEH region and the quantity sold (per day and per year) are presented in Table 2. The six different processed bamboo shoot products sold

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Table 1. Traditional dishes prepared from fermented, roasted and boiled bamboo shoot products in NEH region, India Description of dishes

State

Bamboo shoot products

Local name/dialect

Arunachal Pradesh

Roasted bamboo shoots

Eva/Nyishing

Fermented

Slice, Hikhu/Apatani Crushed, Ekung/Nishies Crushed dry, Eup/Nishies Whole shoot, Hitak/Nishies

This is a pre-cooked/re roasted fresh bamboo shoot. It can be consumed as usual or is consumed by applying it in other vegetable/meat curries. All the fermented products like crushed fermented, dry, sliced or whole shoot fermented are applied in small amounts to other curries (vegetable/non-vegetable) to increase their delicacy.

B. P. Bhatt et al.

Manipur

Fermented

Slice, Soibum/Manipuri

Whole shoot, Soidon/ Manipuri

Slice fermented shoots are boiled/fried with potato, mixed with chilli, salt, Haotonia cordata, etc. It is also cooked along with sh/meat, etc. Slice-fermented shoots are boiled with potato, arum stem and are mixed with chilli, coriander, seeds of Eurayl ferox, salt and dry sh. Small pieces of fermented whole shoots are chopped and boiled/fried with potato, salt, chilli, or with sh/meat etc. Little quantity of crushed-fermented product is applied to pork/beef curry to increase the delicacy. All type of fermented bamboo shoot products are applied in small quantities according to the taste preferred to all type of curries including boil curries, vegetable and non-vegetable dishes.

Meghalaya

Fermented

Crushed, Syrwa/Khasi

Nagaland

Fermented

Slice, Zusem/Ao Crushed, Zutsuk/Ao Crushed dry, Yisu/Ao Whole shoot, Sethu/Ao Squash, Zitzu/Ao

Sikkim

Boiled bamboo shoot

Whole shoot, Mesu/Nepali

It is pre-cooked/boiled bamboo shoots. It may be consumed as such along with bread/biscuits etc. and are applied generally to vegetables and non-vegetable curries.


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in the market places can be categorized as fermented, roasted and boiled forms. Fermented products had the longest availability period with larger quantity sold in the market places than roasted and boiled forms. The availability of fermented slice and fermented whole shoot in Manipur state had longer period compared to that of Arunachal Pradesh and Nagaland. A comparatively large quantity of fermented slice compared with the other bamboo shoot products was sold in Manipur and Nagaland with ca. 105 and 6 tonnes/year, respectively. Crushedfermented moist was observed in Arunachal Pradesh, Meghalaya and Nagaland, whereas crushed fermented dry was observed to be sold only in Arunachal Pradesh and Nagaland. Both crushed fermented moist and dry bamboo shoot products were sold in larger quantity in Arunachal Pradesh compared to other states in the NEH region. Fermented whole shoot was observed in Arunachal Pradesh, Manipur and Nagaland, whereas largest quantity was sold in Arunachal Pradesh with ca. 102 tonnes/year. Roasted bamboo shoot was recorded only in the market places of Arunachal Pradesh with an annual sale of ca. 52 tonnes, whereas ca. 27 tonnes of boiled bamboo shoots was observed to sell in Sikkim. During the year 20032004, the total quantity of annual bamboo shoot products sold in the market places of the NEH region was recorded to be ca. 680 tonnes. Arunachal Pradesh has contributed highest with ca. 481 tonnes/year followed by Manipur, Meghalaya, Sikkim and Nagaland with ca. 114, 39, 27 and 19 tonnes/year, respectively. Table 3 shows the costreturn analysis of fermented, roasted and boiled bamboo shoot products sold in the market places of NEH region. The retail price (per kg) of all the 5 bamboo shoot products sold in Arunachal Pradesh was higher than those sold in other states of the NEH region. Among the six bamboo shoot products, the cost of crushed-fermented dry bamboo shoot available in Arunachal Pradesh and Nagaland was comparatively high whereas, boiled shoots of large bamboo species in Sikkim state were sold at cheaper rate. The gross income per day as well as per annum from the bamboo shoot products (fermented, roasted and boiled) was highest in Arunachal Pradesh with ca. 195 000 Rs/day (US$ 4264) and 32.61 million rupees per annum (US$ 713 099). It was followed by Manipur, Meghalaya, Nagaland and Sikkim with ca. 5.2 (US$ 113 711), 1.2 (US$ 26 240), 0.8 (US$ 17 494) and 0.6 million rupees (US$ 13 120) per annum. Financial investment and physical efforts made for merchandizing bamboo shoot products in the NEH region was also recorded to be highest in Arunachal Pradesh with ca. 15 million rupees per annum (US$ 328 013), followed by Manipur, Meghalaya, Nagaland and Sikkim with ca. 1.4 (US$ 30 614), 0.6 (US$ 13 120), 0.3 (US$ 6560) and 0.1 million (US$ 2186) rupees per annum, respectively. The highest net income from bamboo shoot products after deduction of both nancial investment and physical efforts was observed in Arunachal Pradesh with 17.5 million rupees per annum (US$ 382 681) followed by Manipur, Meghalaya, Nagaland and Sikkim with ca. 3.8 (US$ 83 093), 0.6 (US$ 13 120), 0.6 (US$ 13 120) and 0.5 million rupees (US$ 10 933) per annum, respectively. The total gross income from the fermented,

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Table 2. Fermented, roasted and boiled bamboo shoot products sold in the market places of the NEH region, India (mean SD) Availability of products in the market places (days/year) 180 5 180 5 180 5 180 3 90 6 192 19 190 3 70 5 78 4 90 7 78 11 67 9 70 5 70 5 548 14 48 4 596 18 560 80 82 23 62 41 100 13 20 4 46 9 258 52 162 20 1604 105 53 22 567 65 576 78 2962 290 Products sold (kg/day) Products sold (tonnes/year)

State

Bamboo shoot product

Arunachal Pradesh

Fermented slice Crushed-fermented moist Crushed-fermented dry Fermented whole shoot Roasted whole shoot Total

29.2 3.6 288.7 18.9 9.5 1.0 102.1 11.7 51.8 7.0 481.3 42.2 105.2 2.7 9.1 0.8 114.3 3.5 39.2 5.6 6.4 1.8 0.5 0.2 0.3 0.1 6.7 0.9 1.4 0.3 3.2 0.6 18.5 3.9

B. P. Bhatt et al.

Manipur

Fermented slice Fermented whole shoot Total

Meghalaya

Crushed-fermented moist

Nagaland

Fermented slice Crushed-fermented dry (outer portion/culm sheath)a Crushed-fermented dry (inner portion/rhizome)b Crushed-fermented moist Crushed-fermented dry (mixture of different bamboo species) Fermented whole shoot Total

Table 2. (Continued) Availability of products in the market places (days/year) 15 8 48 6 Products sold (kg/day) Products sold (tonnes/year)

State


Sikkim

Whole shoot boil of narrow bamboo speciesc Whole shoot boil of large bamboo speciesd Total Grand total

246 33 477 52 723 85 5099 525

3.7 0.5 22.9 2.5 26.6 3.0 679.9 58.2

a Basal


b Crushed

part of tender culm sheath of fresh bamboo shoot in dried form. fermented tender rhizomes in dried form. c Narrow bamboo species consist of C. hookeriana. d Large bamboo species consist of D. hamiltonii and D. giganteus.

25

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Table 3. Costreturn analysis of fermented, roasted and boiled bamboo shoot products in the NEH region, India (mean SD) Retail price (Rs/kg) Gross income (Rs/day) Gross income (million Rs/year) Financial investment and wages for mandays (million Rs/year) 3.87 0.29 5.86 0.66 1.69 0.58 2.76 0.21 0.95 0.05 15.13 1.79 1.32 0.03 0.08 0.02 1.40 0.05 0.59 0.02 0.26 0.07 0.14 0.05 0.07 0.02 0.13 0.02 0.17 0.03 0.06 0.01 0.83 0.20 0.02 0.01 0.04 0.02 0.03 0.01 0.05 0.01 0.09 0.01 0.03 0.02 0.26 0.09 Net income (million Rs/year)

States


Arunachal Pradesh

Fermented slice Crushed-fermented moist Crushed-fermented dry Fermented whole shoot Roasted whole shoot Total 45 5 50 5 30 5 41 3 262 12 237 11 19 2 120 12 19 4 1572 524 948 237 1900 247 2400 480 874 171 11 056 2602 3362 943 16 800 2400 24 660 630 2400 200 27 060 830 4.73 0.12 0.46 0.04 5.19 0.16 1.18 0.17

320 30 43 10 322 50 52 15 48 5

51 840 6400 68 972 4515 17 066 7084 29 484 3380 27 648 3744 195 010 25 123

9.33 1.15 12.41 0.81 3.07 1.28 5.31 0.61 2.49 0.34 32.61 4.19

5.46 0.86 6.55 0.15 1.38 0.70 2.55 0.40 1.54 0.29 17.48 2.40 3.41 0.09 0.38 0.02 3.79 0.11 0.59 0.15 0.24 0.06 0.10 0.03 0.04 0.01 0.08 0.01 0.08 0.02 0.03 0.01 0.57 0.14

B. P. Bhatt et al.

Manipur

Fermented-slice Fermented whole shoot Total

Meghalaya

Crushed-fermented moist

Nagaland

Fermented-slice Crushed-fermented dry (outer portion/culm sheath)a Crushed-fermented dry (inner portion/rhizome)b Crushed-fermented moist Crushed-fermented dry (mixture of dry bamboo species) Fermented whole shoot Total

Table 3. (Continued) Gross income (Rs/day) Gross income (million Rs/year) Financial investment and wages for mandays (million Rs/year) 0.03 0.00 0.07 0.02 0.10 0.02 17.48 1.97 883 010 382 244 Net income (million Rs/year)

States


Retail price (Rs/kg)

Sikkim 6642 891 8109 884 14 751 1775 264 677 32 730 5788 0.39 0.04 0.57 0.06 40.38 4.78 0.18 0.02

27 6

0.15 0.02 0.32 0.02 0.47 0.04 22.90 2.84 500 766

Whole shoot boil of narrow bamboo speciesc Whole shoot boil of large bamboo speciesd Total

17 2

Grand total (Rs.)

Grand total

(US$)e

a Basal


b Crushed

part of tender culm sheath of fresh bamboo shoot in dried form. fermented tender rhizomes in dried form. c Narrow bamboo species consist of C. hookeriana. d Large bamboo species consist of D. hamiltonii and D. giganteus. e 1 US$ = Rs. 45.73 in Indian currency (January 2004).

27

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B. P. Bhatt et al.

Figure 9. Net income [after deduction of nancial investment (1)] and employment opportunity (!) in the NEH region, India.

roasted and boiled bamboo shoot products in NEH region, India was computed as ca. 40 million rupees per annum (US$ 874 700), with a net income of ca. 23 million rupees per annum (US$ 502 953), where a total of ca. 17 million rupee per annum (US$ 371 748) nancial investment and physical efforts as mandays were made for merchandizing them. Figure 9 depicts the monetary return, annual income generated (after the deduction of nancial investment made) from the merchandizing of bamboo shoot products and employment opportunity in the NEH region of India. During the study period, the highest income per manday was recorded in Arunachal Pradesh with Rs. 80 per day (US$ 1.75) and lowest in Manipur with Rs. 60/day (US$ 1.31), whereas in Meghalaya, Nagaland and Sikkim this was recorded to be Rs. 65 per day (US$ 1.42). The net income (after deduction of nancial investment) from selling of bamboo shoot products in Arunachal Pradesh could employ most persons (945 persons at Rs. 80 per day (US$ 1.75) throughout the year), whereas in Sikkim state it could generate the least with 22 persons at Rs. 65 per day (US$ 1.42). In Manipur, 220 persons could be engaged in merchandizing bamboo shoot products throughout the year at Rs. 60 per day (US$ 1.31), whereas in Meghalaya and Nagaland it could generate employment for 40 and 31 persons, respectively, at Rs. 65 per day (US$ 1.42). Thus, a total of 1258 persons could be engaged fully or partly for their livelihood through the merchandizing of fermented, roasted and boiled bamboo shoot products in 5 states of the NEH region of India.


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DISCUSSION

The present investigation could provide an idea on the available fermented, roasted and boiled bamboo shoot products consumed as well as sold in the market places of 5 states in the NEH region of India. The highest variety of bamboo shoot products observed in Nagaland and Arunachal Pradesh was due to the higher diversity of ethnic groups in these two states. Different ethnic groups have different indigenous technical knowledge for the processing of bamboo shoot products, although the principle remains same. Arunachal Pradesh has a moderate population with 1.09 million. Largest sale of bamboo shoot products with highest commercial value in Arunachal Pradesh was due to the moderate population with rich bamboo resource in which ca. 80% of the total population belongs to the rural sector who access the resource. Another reason is the long term availability of fermented products with their high demand. Among the bamboo shoot products, the highest sale of crushedfermented moist bamboo products observed in Arunachal Pradesh was due to its low cost with consumability by almost all tribal communities of the state, except the Monpa tribe. The shorter availability period of roasted whole shoot and whole shoot boil in the market places of the NEH region was due to the short bamboo shoot availability period in the forests/homegardens during the rainy season (MayJuly) and limited market days per week. The largest quantity of fermented-slice bamboo shoot in the NEH region, which was recorded in Manipur, was due to its longest availability period in the market places with higher sale. In spite of the consumption of crushed fermented dry bamboo shoots by almost all the tribal communities in Arunachal Pradesh there was a lower sale which was due to a very high market price. As limited ethnic groups of Nagaland consume crushed fermented bamboo shoot products, there was a low sale of this product in few market places of particular localities of Nagaland. Almost all the ethnic groups of Manipur consume fermented slice bamboo shoots as major food item and as food additives in different dishes, whereas, fermented whole shoot was consumed by three communities. In addition, fermented slice bamboo shoots processed in Manipur are also exported to the neighbouring states of NEH region, like Arunachal Pradesh, Nagaland and Assam. Most of the fermented slice bamboo shoots sold in the market places of Arunachal Pradesh was dealt by secondary vendors who purchased and transported it from Manipur due to its better quality and delicacy, which resulted in a higher market price. In Meghalaya, only crushed fermented moist bamboo shoot was observed to be sold by the major three tribal communities, i.e., Khasi, Jaintia and Garo in less quantity compared to the other states of the NEH region, except Nagaland. It may be due to the higher availability of other food/vegetable crops with low price which can substitute costly bamboo shoot products. The unique fermented dry basal portion of tender culm sheath recorded in Nagaland was restricted to the market places of Wokha, Mokokchung and Tuensang

30

B. P. Bhatt et al.

districts. It was used by only 5 tribal communities of the three districts of the state in preparing particular dishes like duck meat, rabbit meat curries, etc. In Nagaland, fermented bamboo shoot products are consumed in large quantities but not through the market places, rather they were processed in household level and preserved for their use throughout the year. In Sikkim, market price of boiled bamboo shoots of narrow bamboo species (Chimonobambusa hookeriana) was higher than that of large species (Dendrocalamus hamiltonii and D. giganteus) due to its more delicacy with sweet taste and its less availability in the natural forests as well as home gardens. A higher number of bamboo shoot products available in the market places of Arunachal Pradesh with larger quantity sold for longer periods, at higher market price, fetched higher annual gross income in this state. Though, the market price of few fermented bamboo shoot products sold in Nagaland was very high, but due to its negligible quantity sold in the market places with limited availability period throughout the year, annual gross income was low. Physical efforts as mandays required for merchandizing of all bamboo shoot products in all states of NEH region were more than that of nancial investments made for purchasing fresh shoots, fuelwood cost, transportation charge and purchasing cost of processed bamboo shoot products in case of secondary vendors. Higher net income generated from processed bamboo shoot products in Arunachal Pradesh was due to the higher gross income with comparatively less nancial investment as well as physical efforts made for their commercialisation. Lowest net income generated from this resource in Sikkim was due to its lowest gross income resulted by low market price and availability for a very short period with higher nancial investment and physical efforts made for commercialisation. Due to the large income generated from bamboo shoot products, Arunachal Pradesh alone could employ ca. 945 persons/year, whereas Manipur could employ ca. 220 persons throughout the year. Overall, fermented, roasted and boiled bamboo shoot products consumed through the market places in the 5 states of NEH region could support ca. 1258 persons throughout the year on a sustainable basis.CONCLUSIONS

Through this study, it can be understood that, in addition to the consumption of fresh bamboo shoots, there is a very high commercial value of fermented, roasted and boiled bamboo shoot products which can be used as a tool for the income generation and creating employment opportunities in the states of NEH region of India. Further, proper planning and implementation of small and large scale industries for bamboo shoot processing units in this region may reduce the unemployment problems and improve the socio-economic conditions of the region. Acknowledgements The authors acknowledge the help and support of tribal communities of all the NEH states, including Sikkim, state for generously providing information during


31

the survey work. Thanks are also due to Indian Council of Agricultural Research (ICAR), New Delhi for providing nancial assistance and Director of the Institute for providing facilities to conduct the work.

REFERENCES1. D. Ohrnberger, The Bamboos of the World. Elsevier, Amsterdam (1999). 2. Y. M. L. Sharma, Bamboos in Asia Pacic Region, in: Bamboo Research in Asia, G. Lessard and A. Chouinard (Eds), pp. 99120. World Publications, Singapore (1980). 3. J. C. Varmah and K. N. Bahadur, Country report and status of research on bamboos in India, Indian Forest Records (Botany) 6, 128 (1980). 4. D. K. Hore, Genetic resources among bamboos of north-eastern India, Journal of Economic Taxonomic Botany 22 (1), 173181 (1998). 5. C. Recht and M. F. Wetterwald, Bamboos. Eugen Ulmer, Stuttgart, Germany (1988) (in German). 6. C. V. Sastry, Bamboos for the 21st Century. International Network for Bamboo and Rattan, Beijing. Accessible at http://www.inbar.org.sg/timber.htm 7. V. Kleinhenz, M. Gosbee, S. Elsmore, T. W. Lyall, K. Blackburn, K. Harrower and D. J. Midmore, Storage methods for extending shelf life of fresh, edible bamboo shoots (Bambusa oldhamii), Post Harvest Biology and Technology 19, 253264 (2000). 8. K. S. Shi, Z. Y. Li, F. M. Lin and R. Zhang, Chinas Country Report on Forestry. Asia Pacic Forestry Sector Outlook Study, Working Paper No. APFSOS/WP/14. Forestry Policy and Planning Division, Rome, Regional Ofce for Asia and the Pacic, Bangkok, FAO, Rome (1997). 9. K. Ueda, Bamboo industry in Japan, present and future, in: Proceedings of the XVII IUFRO World Congress, Division 5, Kyoto, pp. 244255 (1981). 10. B. P. Bhatt, L. B. Singha, K. Singh and M. S. Sachan, Some commercial edible bamboo species of north east India: Production, indigenous uses, cost-benet and management strategies, Bamboo Science and Culture 17 (1), 420 (2003). 11. B. P. Bhatt, L. B. Singha, M. S. Sachan and K. Singh, Commercial edible bamboo species of North Eastern Himalayan region, India: Part I. Young shoot sales, J. Bamboo and Rattan 3 (4), 337364 (2004). 12. Anonymous, State of Forest Report. Forest Survey of India Publication, Ministry of Environment and Forests, Govt. of India, New Delhi (2001). 13. Anonymous, Basis Statistics of North Eastern Region. North Eastern Council Publication, Ministry of Home Affairs, Govt. of India, New Delhi (2002).



Biomass estimation of Bambusa tulda grown at Eastern Terai, NepalB. N. OLI Department of Forest Research and Survey, PO Box 3339, Kathmandu, Nepal

AbstractWith a view to prepare biomass tables of Bambusa tulda grown at Belbari, Morang district of Eastern Nepal, a total of 153 culms was selected from 59 clumps. Measurements of diameter at 15 cm of the base (D15 ), vertical height of the culm, green weight of the culm, branches and foliage were taken in the eld. The samples were oven dried in laboratory at Kathmandu. To estimate the biomass, a regression model was developed on the basis of oven dry and green weight. The model used was W = a + b (D 2 L). Based on the oven dry weight, the R 2 values were obtained for culm, branch and foliage components, which were 92, 81 and 83%, respectively. Similarly, R 2 values for culm and foliage components on the basis of green weight were 92 and 82%, respectively. The R 2 values obtained for branch and foliage components were slightly lower as compared to the culm. This equation could be useful in estimating bamboo biomass of managed natural stands or plantations in similar site conditions. Key words: Biomass; bamboo; Bambusa tulda; Nepal.

INTRODUCTION

Bamboos are the most widely used products, as they are used every day by about 2.5 billion people in the world [1]. In Nepal, they are one of the most common plant species grown on farmland [2]. People perceive this species as an alternate to timber tree species. Moreover, it is also considered as an important component of livelihood strategies of the rural households [2]. With its varied uses such as construction materials, woven products, agricultural implements, fodder, vegetables and scaffolding and in stabilizing slip-prone slopes, bamboos are in great demand by the rural households in Nepal. Occurrence of bamboo is more common in the eastern half of the country from Dhaulagiri to the Sikkim border, as high as 4000 m [3]. In Nepal, so far 12 genera and more than 50 species of bamboo have been recorded [4]. Out of the 75 districts of Nepal, 73 are known to have one E-mail:

[email protected]

34

B. N. Oli

or more species of bamboo. It has been estimated that the total growing stock of bamboo in Nepal is around 15 million m3 with an approximate biomass value of 1060 million tons [5]. Bambusa tulda is occasionally found in the Terai region of Nepal, especially around the Chitwan district of the Central region. It has strong upright culms, but some are very short crooked, with swollen nodes and with heavy branches. Such culms reach a maximum diameter of 7 cm and a length of 15 m, although they are often smaller. As they are very thick-walled, they are used for construction purposes. Leaves can be used for fodder and the shoots are not edible [3]. Despite the multiple benets obtained from bamboos, limited documentation has been published on the biomass production potential. On the basis of oven dry and green weight, a biomass table of B. nutans subspecies nutans has been prepared [6]. Previous studies focused more on distribution, growth performance and culm production aspects. At 4.5 years age, the average diameter, height and survival of plants at Belbari of Morang district were 4.2 cm, 8.7 m and 67%, respectively [7]. As there is a growing demand of bamboo products in the country, information on the estimation of biomass would be benecial for managing the bamboo resources. This paper records information on biomass of B. tulda, useful to forestry professionals, private growers and other interested parties.


The Department of Forest Research and Survey conducted a trial on establishment and management of bamboo at Belbari, Morang district of eastern Nepal in 1991. B. nutans subspecies nutans (Taru Bans), B. nutans subspecies cupulata (Mal Bans), B. tulda (Japhta Bans), B. balcooa (Dhanu Bans) and Dendrocalamus giganteus (Rakshasi Bans) were planted at Belbari [7]. Of the 5 bamboo species planted, B. tulda was selected for the study. The reason for selecting this species for biomass estimation was its varied use and wide occurrence in Nepal and lack of comprehensive documentation on biomass estimation of the species. The site is located at an altitude of 155 m above sea level (asl) and the soil is loamy to silt loam in nature. There was Sal (Shorea robusta) forest 3 to 4 years before the establishment of the trial. The average annual rainfall is 1737 mm and average maximum and minimum temperature are 30 C and 18.2 C, respectively [8]. The plants produced from single node culm cuttings taken from Sunsari district of eastern Nepal were the source of materials for planting. The cuttings were propagated in the Tarahara nursery located at Sunsari district, before they were taken for planting site at Belbari. Soil heaping was carried out in each clump in 1993 and the oldest culms were cut and removed in the winter of 1996 [7]. The age of the culms was estimated with the help of watchers who have been working at the research plot since its establishment. The age of all the clumps is 12 years, since it was established in 1991. Fiftynine clumps comprising culms of varying age (from 1 to 12 years) and diameter

Biomass estimation of Bambusa tulda

35

classes (D15 from 4 to 12 cm) were chosen. The total number of culms from each clump was counted. From each clump, at least 2 culms of various age and diameter classes totalling 153 were cut 15 cm from the ground for the study. Measurements of diameter at 15 cm of the base (D15 ), vertical height of the culm, green weight of the culm, branches and foliage were taken in the eld. Seventeen representative culms were selected for sub-samples of culm, branch and foliage. These sub-samples were brought into the laboratory in Kathmandu and oven-dried at 105 C until a constant weight was attained. To convert the fresh weight of culm, branch and foliage components into oven dry weight, sub-samples percentage dry matter values were used. We used the formula dry matter value = ((oven dry weight/fresh weight) 100) to obtain a conversion factor of 0.480, 0.531 and 0.359 for converting fresh weight to oven dry weight of culm, branch and foliage, respectively. Out of 153 datasets, 135 datasets were used to develop the regression equation and the remaining 18 datasets representative of all diameter classes were used for validation purposes. To estimate the biomass, a regression model was developed on the basis of oven dry weight. Biomass tables for culm and foliage were also prepared on the basis of green weight. Of the various models tested with the use of 135 datasets, the model developed was W = a + b (D 2 L), where W is the weight in kg, D is the diameter at 15 cm, L is the vertical length of the culm, and a and b are the regression constants. A prediction error for oven-dried weight of culms, branch and foliage was calculated to measure the validity of the model [10]. Similarly, a prediction error was calculated for green weight of the culm, as follows: prediction error = ((sum of actual weight sum of predicted weight/sum of actual weight) 100).

RESULTS AND DISCUSSION

Dry matter content A total of 53.1% dry matter content was found in the branch of B. tulda. The dry matter content values of culm and foliage are 48 and 35.9%. The dry matter content of culm, branch and foliage components of B. nutans subspecies nutans grown at the same site were 47.3, 41.1 and 38.2%, respectively [6]. The gures of dry matter content of culms and foliage of both the species were close, except for the branches where there is a big difference. Biomass estimation on the basis of oven dry weight Using the regression model of W = a + b (D 2 L), the biomass of all the components (culm, branch and foliage) was calculated. Based on the oven-dried weight, the R 2 values obtained for culm, branch and foliage components were 92,

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B. N. Oli

Table 1. Biomass for culm on the basis of oven dry weight (in kg) D15 Height (m) (cm) 5 6 7 4 5 6 7 8 9 10 11 12 2.52 2.97 2.68 3.22 3.88 2.84 3.47 4.24 5.15

8 3.72 4.60 5.64 6.84

9 3.97 4.96 6.13 7.48 9.01

10 5.32 6.62 8.12 9.82 11.72

11 7.11 8.76 10.63 12.72 15.03

12 7.60 9.40 11.44 13.72 16.24 19.00

13 10.04 12.25 14.72 17.45 20.44

14 10.68 13.06 15.72 18.66 21.88

15 13.87 16.72 19.87 23.32

16 17.72 21.08 24.76

17 18.72 22.29 26.20

18 19.72 23.50 27.64

All tables provide information on the estimated biomass of the culms, branches and foliage prepared on the basis of oven dry or green weight. The R 2 value of more than 90% shows the good estimation of culm biomass; less than 90% is a less reliable estimation. a = 1.72, b = 0.01, standard error = 1.46, R 2 = 92%. Table 2. Biomass table for branch on the basis of oven dry weight (in kg) D15 (cm) 4 5 6 7 8 9 10 11 12 Height (m) 5 0.73 0.84 6 0.77 0.89 1.04 7 0.81 0.95 1.13 1.34 8 1.01 1.21 1.45 1.73 9 1.07 1.29 1.56 1.87 2.22 10 1.38 1.68 2.02 2.41 2.85 11 1.79 2.17 2.60 3.08 3.61 12 1.90 2.31 2.78 3.31 3.89 4.52 13 2.46 2.97 3.54 4.17 4.85 14 2.61 3.16 3.77 4.44 5.18 15 3.34 4.00 4.72 5.52 16 4.23 5.00 5.85 17 4.46 5.28 6.18 18 4.69 5.56 6.51

a = 0.548, b = 0.0023, standard error = 0.61, R 2 = 81%.

81 and 82.5% respectively (Tables 13). The R 2 values for branch and foliage were slightly lower as compared to the culm. The prediction error calculated for oven-dried weight of culms, branch and foliage components were 4, 22 and 19%, respectively. It has been reported that prediction error of less than 15% validates the models [10]. While estimating culm biomass on the basis of oven dry weight, the prediction error is only 4%, which veries the validity of the model. However, it would be better to test the model for estimating biomass in different site conditions. Due to the large variation in branching pattern in similar sized culms of this species, the prediction error became higher (22%) than for the culm and foliage component. The prediction error for foliage was found to be 19%. It is argued that the prediction of leaf yield from biomass equations is less accurate and more site-

Biomass estimation of Bambusa tulda Table 3. Biomass table for foliage on the basis of oven dry weight (in kg) D15 (cm) 4 5 6 7 8 9 10 11 12 Height (m) 5 0.03 0.07 6 0.05 0.09 0.14 7 0.06 0.11 0.17 0.24 8 0.13 0.20 0.28 0.38 9 0.15 0.23 0.32 0.43 0.55 10 0.26 0.36 0.48 0.62 0.77 11 0.40 0.53 0.68 0.85 1.03 12 0.44 0.58 0.75 0.93 1.13 1.35 13 0.63 0.81 1.01 1.23 1.47 14 0.69 0.88 1.09 1.32 1.58 15 0.94 1.17 1.42 1.70 16 1.25 1.52 1.81 17 1.33 1.61 1.93

37

18 1.41 1.71 2.04

a = 0.031, b = 0.0008, standard error = 0.198, R 2 = 82.5%. Table 4. Biomass table for culm on the basis of green weight (in kg) D15 Height (m) (cm) 5 6 7 4 5 6 7 8 9 10 11 12 5.06 5.89 5.36 6.36 7.58 5.65 6.82 8.24 9.93

8 7.28 8.91 10.83 13.05

9 7.74 9.57 11.74 14.24 17.07

10 10.24 12.65 15.42 18.57 22.08

11 13.55 16.60 20.06 23.93 28.20

12 14.46 17.79 21.56 25.78 30.44 35.55

13 18.97 23.06 27.63 32.68 38.21

14 20.16 24.56 29.48 34.92 40.88

15 26.06 31.33 37.16 43.54

16 33.18 39.40 46.20

17 35.03 41.63 48.87

18 36.88 43.87 51.53


specic than for the components of stem, branch and total tree weight [9]. Biomass tables for culm, branch and foliage components based on oven-dried weight are presented in Tables 1, 2 and 3, respectively. Biomass estimation on the basis of oven dry weight Biomass equations are normally prepared on an oven dry weight basis to facilitate comparison with other sites, species and seasons [10]. However, bamboo culms are sold on a fresh weight basis in both the rural and urban areas of Nepal. Therefore, a biomass table for culm based on green weight was also prepared (Table 4). Bamboo leaves are used as fodder in some areas where there is fodder decit. Leaves of B. tulda can be used as fodder [3]. Hence, a biomass table for foliage was also prepared on the basis of green weight (Table 5). Based on the green weight, the R 2 values obtained for culm and foliage components were 92 and 82%, respectively.

38

B. N. Oli

Table 5. Biomass table for foliage on the basis of green weight (in kg) D15 (cm) 4 5 6 7 8 9 10 11 12 Height (m) 5 0.08 0.17 6 0.11 0.22 0.35 7 0.14 0.27 0.42 0.60 8 0.32 0.49 0.70 0.94 9 0.37 0.56 0.80 1.07 1.37 10 0.64 0.90 1.20 1.54 1.92 11 0.99 1.32 1.70 2.12 2.58 12 1.09 1.45 1.86 2.32 2.82 3.37 13 1.58 2.02 2.52 3.06 3.66 14 1.71 2.18 2.72 3.30 3.95 15 2.35 2.92 3.55 4.24 16 3.12 3.79 4.52 17 3.32 4.03 4.81 18 3.52 4.27 5.10


The prediction error is only 7% while estimating culm biomass on the basis of green weight. Biomass tables based on green weight for culm and foliage are given in Tables 4 and 5, respectively. It was reported from India that total biomass of planted B. arundinacea (retz.) wild of 3 years age was 8528 kg/ha [11]. The total above ground biomass of D. strictus in India was 422 tons/ha [12]. On the other hand, for B. bambos in India the gure ranges from 122287 tons/ha [13].

APPLICABILITY OF THE TABLES

Considering the wide use of bamboos these days, the biomass tables may provide useful information on above ground biomass to forestry professionals, bamboo growers, forest user groups and other interested parties. Although the biomass estimation is conned to the site condition of Belbari of Morang district, it can be applied to other similar site conditions as well. While estimating culm biomass on the basis of oven dry weight, the R 2 of more than 90% and prediction error of only 4% veries the validity of the model. Similarly, the prediction error of 7% for the biomass estimation of culm on the basis of green weight also veries the validity of the model. This equation could be useful in estimating bamboo biomass of managed natural stands or plantations in similar site conditions. On the other hand, the biomass estimation on the basis of oven dry weight of branch and foliage components gave a higher prediction error than a normal range of within 15%. Therefore, it would be better to test the model for estimating biomass in different site conditions.

Biomass estimation of Bambusa tulda

39

REFERENCES1. J. M. Scurlock, D. C. Dayton and B. Hames, Bamboo: An Overlooked Biomass Resource? ORNL/TM-1999/264, 34 pp. Oak Ridge National Laboratory, Oak Ridge, TN (2000). 2. A. N. Das and B. N. Oli, Tree growing practices on farmland: an option for sustaining rural livelihoods, Banko Janakari 11 (2), 812 (2001). 3. C. M. A. Stapleton, Bamboo of Nepal: An Illustrated Guide. Royal Botanical Gardens, Kew (1994). 4. A. N. Das, Manual of Bamboos in Nepal. A draft report submitted to tree improvement and silviculture component (TISC). TISC, Kathmandu (2002). 5. M. B. Karki and J. B. S. Karki, National Bamboo and Rattan Information Database, Nepal. Tribhuvan University, Institute of Forestry, Pokhara (1995). 6. B. N. Oli, Biomass estimation of Bambusa nutans subspecies nutans grown at Eastern Terai, Nepal, Banko Janakari 13 (1), 4346 (2003). 7. H. B. Thapa, A. N. Das and B. N. Oli, Growth performance and culm production of bamboo at the Eastern Terai, Nepal, Banko Janakari 8 (1), 1318 (1998). 8. HMG/N, Climatological Records of Nepal 19911994. Department of Hydrology and Meteorology. Kathmandu (1997). 9. T. Satoo and H. Madgwick, Forest Biomass, 150 pp. Martinus Nijhoff/Dr. W. Junk, Den Haag (1982). 10. T. Hawkins, Biomass and volume tables for Eucalyptus camaldulensis, Dalbergia sissoo, Acacia auriculiformis and Cassia siamea in the Central Bhabar-Terai of Nepal. O. F. I. Occasional Papers No. 33. Oxford Forestry Institute, Oxford (1987). 11. N. S. Rao and C. Nagarajaih, Evaluation of Bambusa arundinacea (Retz.). Wild for growth and biomass production in dryland ecosystem, MYFOREST 27 (1), 7074 (1991). 12. S. K. Tripathi and K. P. Singh, Productivity and nutrient cycling in recently harvested and mature bamboo savannas in the dry tropics, Journal of Applied Ecology 31 (1), 109124 (1994). 13. P. Shanmughavel and K. Francis, Biomass and nutrient cycling in bamboo (Bambusa bambos) plantations of tropical areas, Biology and Fertility of Soils 23 (4), 431434 (1996).



Foliage decomposition and nutrient release dynamics of Bambusa balcooa and Bambusa pallida in a 9-year-old jhum fallowK. ARUNACHALAM , K. UPADHYAYA and A. ARUNACHALAMDepartment of Forestry, North Eastern Regional Institute of Science and Technology, Nirjuli 791109, Arunachal Pradesh, India

AbstractLitter decay and nutrient release rates of leaf and leaf sheath litters of Bambusa balcooa Roxb. and B. pallida Munro were determined using the litter-bag technique in a 9-year-old jhum fallow in the humid tropics of north east India. C concentration was highest in leaf and leaf sheath litters of B. pallida, while N and lignin concentrations were greater in B. balcooa litter. Both leaf and scale leaf litters of B. balcooa and B. pallida showed similar decomposition patterns. The daily decay constants did not differ signicantly between the two litter types and among bamboo species studied. Nonetheless, mass-loss rates during decomposition of the leaf and leaf sheath litters of both the species showed positive correlations with incubation period (the time after burying the samples in the soil). In general, until 120 days of incubation, there was N immobilization and later during the study period rapid release occurred. The release of N from B. pallida is greater than B. balcooa as per KN values. P was initially being immobilized followed by a gradual release after 120 days of litter decomposition in B. balcooa. In B. pallida, no denite pattern was observed. The rate of weight loss and N release showed signicant positive relationships with lignin and N concentrations and lignin/N, C/P and N/P ratios, and negative relationships with C and P concentrations and C/N ratio. However, release rates of P did not show signicant correlations with most chemical compositions of the litter except with initial P concentration, C/P ratio and lignin/N. Key words: Bamboo; decomposition; humid tropics; litter; nitrogen; phosphorus.

INTRODUCTION

Bamboo constitutes one of the dominant secondary successional vegetation types in the majority of the northeast Indian forests. Out of 18 genera and 128 species of bamboos of India [1], Arunachal Pradesh alone harbours 16 genera and 63 species [2]. Abandoned jhum (shifting agriculture) lands and forest clearings To

whom correspondence should be addressed. E-mail: [email protected]

42

K. Arunachalam et al.

form favourable habitats for bamboos to invade, colonize and establish faster when compared to broadleaved native species [3], resulting in pure and/or mixed bamboo forests. Due to its abundance and faster re-growth, these bamboo species meet a variety of socio-economic and ethno-botanic human needs in the region. Nevertheless, the role of bamboos in soil nutrient cycling in degraded sites has been less studied [4 7], unlike other broadleaved forest tree species [8 10]. Recycled nutrients from decomposing plant litter are one of the main nutrient sources for maintaining growth of forest vegetation [11]. Bamboos in this part of the world are mainly distributed in nutrient poor soils. Hence, the nutrient release from litter decomposition may play an important role in re-establishing the nutrient cycling in nutrient poor soils, particularly when the ecosystem is undergoing recovery following disturbance [12]. The objective of the present study was to determine the rates of decomposition and nutrient release through the leaf and leaf sheath litters of two lower altitude (100 to 600 m above sea level (asl)) bamboos, Bambusa balcooa Roxb. and B. pallida Munro, growing in a 9-year-old jhum fallow in the humid tropics of Arunachal Pradesh, north-eastern India.


Study site The study was conducted in a bamboo forest (9 years old) developed on a fallow agricultural land (1.74 ha) located at an altitude of 132 m above sea level in humid tropics of Arunachal Pradesh (26 28 29 30 N latitude; 91 30 97 30 E longitude), northeastern India. The average annual rainfall of the place was about 1800 mm with mean maximum and minimum air temperatures 33 and 18 C, respectively. At the time of sampling (FebruaryMarch) the average soil temperature recorded was 23 C. The climate was monsoonal with three seasons: winter (OctoberFebruary), spring/summer (MarchMay), monsoon (JuneSeptember). Almost 80% of the total annual rainfall occurs during MaySeptember. The study site was dominated by two fast growing and clump forming bamboo species having average height of 15 to 20 m and a mean culm diameter of 69 cm (Table 1).Table 1. Characteristics of bamboo species in the study site Species No. of clumps per ha 89 7 137 11 No. of culms per clump 23 6 37 7 Height (m) Average diameter (cm) Clump 470 28 415 23 Culm 92 61

Bambusa balcooa Bambusa pallida

19.6 1.2 15.6 0.8

Values are means SE (n = 5).

Foliage decomposition and nutrient release dynamics of B. balcooa and B. pallida

43

Soil sampling and analytical procedures Topsoil (010 cm) under the canopy of B. balcooa and B. pallida was collected in bulk during FebruaryMarch, 1999. The soils were sieved through a 2-mm mesh and the initial pH, moisture content (gravimetric method), and concentration of ammonium-N (indophenol blue method) and nitrate-N (phenol disulphonic acid method) were determined within 24 h after sampling. The remaining soil samples were air-dried and analyzed for texture, water holding capacity (WHC), soil organic carbon (SOC), total Kjeldahl nitrogen (TKN) and available-P according to standard procedures [13, 14]. The soil was loamy sand and acidic (pH 5.96.5). Water holding capacity and clay content of soils were relatively greater in B. balcooa soil (64% and 9.5%, respectively). On the other hand, soil organic C, total Kjeldahl N and available P were higher in B. pallida soil (1.9%, 0.46%, 10.69 g g1 ). Litter sampling and analytical procedures Freshly fallen foliage litter samples of the two bamboo species were collected from ve randomly selected clumps of each species during FebruaryMarch 1999. The litter was sorted into leaves and leaf sheath and air-dried. Sub samples of litters were oven-dried at 105 C for 24 h in order to determine their dry weights and for moisture correction. Ash content of litter was determined by igniting ground samples in a Mufe furnace at 550 C for 6 h. C content was calculated taking 50% of ash-free weight [14]. Total Kjeldahl N was determined using the semi-micro Kjeldahl procedure and total P was estimated using the molybdenum blue method. Lignin, cellulose and bre contents were also determined [15]. The data given in Table 2 are the mean values of the ve replicated clumps for each species and litter type in the study site. The sorted foliage litter samples from ve clumps of each species were then bulked together to form four categories of samples (2 species 2 litter type) for further study. Air-dried litter samples equivalent to 10 g of oven-dry weight was placed in a nylon litter-bag (1 mm mesh; 15 cm 15 cm). Sixty bags were prepared for each litter fraction of a given species. The bags were equally distributed in ve clusters in the site. In order to avoid disturbances from grazing animals, the bags were buried in the top 05 cm soil layer below the canopy of respective species during March 1999. Five bags per litter type were retrieved at 60 days interval. Each time, the sample from each bag was cleaned of adhering plant parts and soil particles, oven-dried at 105 C for 24 h and weighed. The dried samples were ground and analyzed for N and P using the standard procedures given in Anderson and Ingram [15]. Computation and statistics Organic matter decay constants for the leaf and leaf sheath litters were computed using negative exponential decay model of Olson [16]: X/X0 = exp(kt),

44


Table 2. Initial chemical composition of bamboo litter B. balcooa C (%) N (%) P (%) Lignin (%) Cellulose (%) Fibre (%) C/N Lignin/N N/P C/P Lignin/P Leaf 44.56a (0.138) 1.15a (0.063) 0.031a (0.001) 31.2a (0.339) 28.26a (0.500) 52.08a (0.563) 38.75a 26.96a 37.10a 1437.42a 1006.45a Leaf sheath 46.71b (0.367) 0.34b (0.031) 0.032a (0.003) 25.1b (0.473) 29.63a (0.438) 35.41b (0.491) 137.38b 73.53b 26.25b 1459.69a 784.38b B. pallida Leaf 47.82a (0.129) 0.84a (0.049) 0.023a (0.001) 29.3a (0.375) 30.34a (0.469) 49.01a (0.518) 56.93a 34.52a 14.78a 2079.13b 1273.91c Leaf sheath 48.92b (0.326) 0.34b (0.040) 0.063b (0.002) 20.4b (0.491) 31.05a (0.388) 34.31b (0.339) 143.88b 58.82b 5.40b 776.51c 323.81d

n = 5; Values in parentheses denote SE. In each species, the values with similar letters across leaf and leaf sheath categories are not signicantly different at P < 0.05.

where X is weight remaining at time t, X0 is initial weight and k is the decay rate coefcient. The times required for 50% (t50 ) and 99% (t99 ) decay were calculated as t50 = 0.693/k and t99 = 5/k. The effect of initial litter chemistry and rainfall (data obtained from Doimukh Meteorological Station, which is within 1 km radius of the study site) on the decay rate was tested using the linear regression function, Y = a + bX [17]. Polynomial equations were used to characterize the observed decay pattern [18].

RESULTS

Initial litter chemistry C concentration was about 23% higher in the two litter types of B. pallida, while N concentrations were greater in B. balcooa leaf litter by about 0.3% (Table 2). N concentrations were found to be same in leaf sheath litters of both species. Concentration of P of both the litter types of B. balcooa was similar while it was signicantly different in the litter types of B. pallida showing higher P concentrations in leaf sheath by a difference of 0.040%. Among the species, B. balcooa leaf had a higher P concentration (0.008%), whereas the opposite trend was recorded in case of leaf sheath litter (higher by 0.029%). Lignin concentration was larger in B. balcooa litters, while the C/N ratio was higher in the other species.

Foliage decomposition and nutrient release dynamics of B. balcooa and B. pallida Table 3. Annual dry matter decay constants of leaf and leaf sheath of two bamboo species Decay parameter % mass loss day1 k (year1 ) t50 (days) t99 (days) B. balcooa leaf 0.40 8.03 31.50 227.27 leaf sheath 0.39 5.84 43.31 312.50 B. pallida leaf 0.40 8.03 31.50 227.27

45

leaf sheath 0.40 8.03 31.50 227.27

In general, the leaf sheath had greater C/N and lignin/N ratios. N/P ratio was comparatively higher in leaf samples than in the leaf sheath in both species. Among species, B. balcooa registered greater N/P ratios. Litter decay Both leaf and leaf sheath litter materials of B. balcooa and B. pallida showed similar decay patterns (Fig. 1). However, decomposition rate exhibited a signicant variation in the two species of bamboo, at least up to 180 days of incubation. In B. balcooa, during the initial 120 days of incubation, the rate of decomposition was slow both in leaf (0.14% weight loss day1 ) and leaf sheath (0.15% weight lossday1 ) litter, and then the decay rate continued to increase until the end of the study period. However, in B. pallida the decomposition rate increased rapidly during initial 60 days (0.28% weight loss day1 ), which continued up to 120 days (0.230.33% weight loss day1 ) and then a signicant decrease (0.200.47% weight loss day1 ) was noticed between 120 and 180 days of incubation, afterward both species showed almost similar pattern of decomposition. Nevertheless, the net weight loss rate was almost similar in the two litter types of both the species. The undecomposed litter at the end of the study remained highest in the leaf sheath of B. pallida (7%) and in all other cases, only 3% of the initial mass was remaining at the end of the study. The mean weight loss per day was similar in leaves and leaf sheath of B. balcooa and B. pallida (Table 3). The decay constants (k) did not differ much between the two litter types and among bamboo species studied (Table 3). Nutrient (N and P) dynamics The concentration of N uctuated in the decomposing B. balcooa leaves during the study period. However, in the rest of the samples it increased with time (Fig. 2a). Nevertheless, the N immobilization and release rates were different through time. In general, until 120 days of incubation, there was a tendency of N immobilization and then rapid release occurred, which continued throughout the study period (Fig. 3a). In general, P concentration increased up to 180 days and then decreased rapidly in both species (Fig. 2b). Initially P was immobilized followed by a gradual release

46


Figure 1. Foliage litter decay pattern in two bamboo species.

after 120 days of litter decomposition in B. balcooa and B. pallida. P release patterns of leaf litter and leaf sheath were different (Fig. 3b).

Effect of litter quality on decomposition and nutrient release rates Weight loss and nutrient release rates of different components were correlated with lignin, C, N and P concentrations and ratios of lignin/N and C/P and N/P. We found strong positive correlation of lignin and N concentrations with weight loss and N release rates. However, only P concentration exhibited a signicant positive correlation with P release rate (Table 4). The other litter chemical quality variables like lignin/N, C/N, C/P and N/P either exhibited positive or negative correlation with weight loss and nutrient release.

Foliage decomposition and nutrient release dynamics of B. balcooa and B. pallida

47

(a)

(b)Figure 2. N (a) and P (b) concentration (%) during litter decomposition of B. balcooa ((F) leaf, (2) leaf sheath) and B. pallida ((Q) leaf, (E) leaf sheath).

DISCUSSION

Decomposition dynamics Overall, the amount of litter remaining at the end of the study period was 37%. Nevertheless, the pattern of litter decomposition varied between litter types and species. In B. balcooa, the rate of decomposition was slow up to 120 days of incubation. This may be attributed to the time taken by microorganisms to colonize and establish on the litter materials as these litter samples had greater lignin and cellulose contents when compared to B. pallida [19, 20]. During monsoon, i.e., after 60120 days of incubation, the decay rate rose due to greater microbial activity. In this context, several authors have reported faster rate of decomposition during rainy season in the tropics [21]. Relatively higher temperature and moisture conditions during monsoon favoured decomposition of bamboo leaf litter in China

48


(a)

(b)Figure 3. N (a) and P (b) remaining (% of initial) in B. balcooa ((F) leaf, (2) leaf sheath) and B. pallida ((Q) leaf, (") leaf sheath).

[6] and southern Western Ghats of India [7]. Coincidently, we obtained a signicant relationship between mass loss and rainfall (r = 0.451, df = 19, P < 0.05). The C/N ratio of plant litter has frequently been negatively correlated with the decomposition rates [22, 23]. We also observed such a relationship in this study. Among other litter quality parameters, initial N and lignin concentrations inuenced the litter decay pattern [24 26]. For instance, the faster rate of decay in leaf litter compared to leaf

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