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Research on Bamboo planting tecnique for bamboo shoot production Le Quang Lien, Nguyen Danh Minh Cau hai Silvicultural Experimentation Research Centre

I. Introduction There are in the world 1,250 bamboo species of 75 different genera. They are distributed in almost all climatic regions (tropical, temperate sub - tropical) from sea level elevation to 4,000m above sea level such as on the side of Hymalaya mountain range. A large part of important bamboo species are distributed in wide areas in the Asian countries. Bamboos have many uses in the people's life and they are closely linked with the Vietnamese peasants. According to the Indochinese flora (By Lecomte), there are in Vietnam 61 different bamboo species. According to documents from surveys by Phan Ke Loc, Vu Van Dung (1976) there are in North Vietnam alone 45 bamboo species of 15 genera. The mid - region of North Vietnam with tropical monsoon climate is the very cradle of bamboo species. In the regions of the Lo, Gam and Chay rivers alone there are already 33 bamboo species belonging to 6 genera (The Committee on North Vietnam Flora, Forestry Directorate - 1974). In Vietnam, research on bamboos began in early 1960s. From 1986 now bamboos have been planted on large scale to meet the requirements of constructional material, paper raw material, bamboos articles for export. Besides useful bamboo culms, bamboo shoots serve as a sort of foodstuff, a clean, delicious and valuable vegetable on home market and for export. In 1995 some regions did plant bamboos for bamboo shoots production but most of the species planted are of Taiwan, China origin. Vietnam also has many bamboo species the shoots of which can serve as a delicious foodstuff and the planting of these species for bamboo shoots production is a practical demand. Therefore the Cau Hai Silvicultural Experimentation Research Centre has conducted the research subject: Research on bamboo planting technique for bamboo shoots production.

II. Research methodology 2.1. Method of data and information collection. - Method of documents studying: Sources of data and information from published scientific reports, reviews on bamboos; document on soils, natural and socio- economic conditions in the region. - Experimental ecology method: Combined study in nursery and in the forest; available data and observation. Establishment of experimental plots for data collection, each species 4 plots, each plot 30 clumps, 3 replicated. Data are collected from the plots as required by research content. 2.2. Data proccessing method: Analysis, synthesis and treatment of data on computer with Excel foftware 2.3. Surveying and studying method Carrying out study on Taiwan bamboo plantation modelin Tan Yen (Bac Giang prov.) Chinese bamboo plantation model in Binh Phu (Binh Phuoc prov.).... in Tan Loc (Dong Nai prov.) for bamboo shoots production. 2.4. Research targets 2 bamboo species: Dendrocalamus membrenaceus and Dendrocalamus sp.

III. Research results 3.1. Characteristics of Dendrocalamus membranaceus Munro. This species belongs to sub-familly Bambusoideae order Graminales. This is a sympodial bamboo species. D. membranaceus has round culm, slightly tapering with many branches. Branch is thornless and is easily used for propagation. The culm is 18 - 20cm in length and 8 - 12 cm in diameter, fresh weight: 40 - 50 kg and up to 70 kg in some cases. The culm is stiff with rather highcellulose content (46.5% at base section, 57.7% in the middle and top sections). The value of D. membranaceus is not only as constructional material but also as rayon and paper raw material, flooring parquet, in house decorations and mats for export. Shoots of D. membranaceus is delicious food stuff with high content of nutrients (percentages in dry matter). Total sugars 20.7%, total N

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3.10%, protein 19.37%, amine acids 2.10%, cellulose 28%, vitamin C 167.20% (mg/ 100g). D. membranaceus growsfast 5 years after planting harvesting can begin the harvesting can last 40 - 50 consecutive years. This is a species once planted allows many harvests by selective exploitation. Only over 3 - year old culms are harvested, 1 - 2 year old culms are left over to produce new bamboo shoots and culms (exploitation intensity is usually 30% of the growing stock. Exploitation cycle is short once in 1 or 2 years). The harvest is from 1,200 to 1,400 culms/ ha. Previously the planting of bamboos in general and D. membranaceus in particular was mainly with stumps. In the past years (1986 - 1990) The Cau Hai Silvicultural Experimentation Research Centre had succeeded in D. membranaceus propagation by branch layering with polythene wrapping. One remaining problem with D. membranaceus now is the price of its shoots is very low (USD 0.9/ kg fresh weight) as compared with the shoots of some other bamboo species (shoots of Taiwan bamboo for example: USD 4/ kg fresh weight). 3.2. Characteristics of Dendrocalamus sp. This species belongs to sub-familly Bambusoideae, order Graminales. Its local name are Tre Gay, May thoc. This is a sympodial bamboo species, developing in clumps with bent top. The culm is 13.18 m high, 6 - 11cm in diameter. Old culm is yellowish green in colour, internode 25 - 40cm long, the culm wall is 12 - 15 mm thick. This species is found at < 400m elevation, < 200 slopes, at mountain side and foot, along streams. Shoot producing season is June - July. This species does flower and regenerates by seed (Na Hang, Tuyen Quang prov.) Dendrocalamus sp. is planted with stumps. The culm is stiff with large scions, thin culm wall is easily attacked by termites and borers, therefore the culm are little used in construction but are used as paper raw material. Dendrocalamus sp. shoots are use as a delicious food stuff and are usually dried in the sun for dried bamboo shoot. 3.3. Law of shoot producing Dendrocalamus membranaceus and Dendrocalamus sp. are both sympodial bamboo species, season of concentrated shoot production is rainy season (May - September). They are both light-demanding species and require good soil with large ecological range (almost the whole North Vietnam); Rhizome having two rows of scions on both sides, these scions (dormantbuds) can develop into shoots and then culms. After planting bamboo plantation produces shoots annualy in rainy season, from May to September. Bamboo plants that produce shoots are those below one year of age. Each bamboo plant below 1 year of age has from 8 to 14 scions at its base but only 2 - 4 shoots are produced and the ratio of shoots tthat develop into culm is very low. (More or less one new culm/ one old culm). There are some factors that affect the growing process of the shoot firstly, strong plants produce large shoots with fast growth, ratio of dead shoots is low. First batch of shoots usually consists of strong shoots because on the same conditions rhizome all dormant scions enjoy the same conditions of soil and climate, the more vigourous dormant scions would first develop into shoots, the less vigourous scions develop into shoots later. The shoots of late batch are usually harvested as foodstuff. Secondly the time for taking shape of the shoot from the time it protrudes from the ground till the time its top looks like a swift,s tail depends on its diameter. Large shoot requires more time for taking shape sometimes up to 100 days. Favourable weather shortens the time for taking shape. Thirdly, lower planting density results in shorter time for taking shape than higher planting density Time of shoot production of Dendrocalamus membranaceus and Dendrocalamus sp. (M: number of shoots)

Species Dendrocalamus sp Dendrocalamus membranaceus

June M 544 720

% 46 38

July M 38 ? 629

% 27 33

August M % 165 14 148 7

September M % 117 10 196 10

October M % 17 1 176 9

The above data show that concentrated shoot production of both Dendrocalamus sp and D. membranaceus is in June and July (D. membranaceus 71%, Dendrocalamus 73%) and in the month of highest rainfall. Total rainfall of May, June, and July is 852mm representing 53% of the total annual rainfall. Mean temperature of these 2 months is also highest in the whole year (280 C). 3.3.1. Time of shoot production of D.membranaceus. Data from monitoring of the time of shoot production of D. membranaceus (M: number of shoots)

Month Hill1

June M 252

% 38

July M 305

% 46

August M % 15 2

September M % 63 9

October M % 17 2

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Hill 2 Hill 3

263 1653

41 70

320 425

51 18

7 46

1 1

22 83

3 3

15 144

2 6

The above data show that with the plantations of the same age concentrated shoot production season is June, July. In hill 1 the number of shoots produced represents 84% of total shoots produced in june and July represents 92% of total shoots produced in a year. In hill 3 the number of shoots produced in June and July represents 88% of total shoots produced in a year. 3.4. Effect of size of planting hole Local land preparation i.e. digging of planting holes of various sizes brings about the following results:

Species Size of planting holes 0,6x0,6x0,5m 1x1x0,5 m 1,5x1,5x0,5m 2x2x0,5 m

D. membranaceus Culms/clump Mean D (cm) ( tree) 7,2 3,62 8,7 3,95 10,3 4,49 10,0 3,96

Dendrocalamus Culms/clump MeanD (cm) ( tree) 3,35 4,07 7,23 4,42 6,67 4,13 4,08 3,61

Mean H (m) 3,03 6,05 5,81 5,24

MeanH (m) 3,76 5,05 4,40 4,75

The above data allow remarks: Size of planting holes exerts great effect on the growth of the plantation. With planting holes of 1m x 1mx 1.5m, 2m x 2m in the surface and 0.5m in depth, mean number of culms per clump is all 1.2 to 1.8 times more than with normal planting holes (60cm x 60cm x 50cm). After 1 month the dug earth must be used to fill the planting hole before planting and this must be the suface soil, filling at 2/ 3 the height of the hole. The earth in the hole must be broken small thoroughly mixed with farmyard manure 10kg/ hole or NPK - 1kg/ hole. 3.5. Effect of fertilizer application on D. membranaceus plantation

Plot Indices Total shoots produced Total dying shoots Total shoots developing into culms Productivity campared with control

I

II

III

Control

1139 437 702

996 416 580

1253 603 650

429 163 266

263,9

218,04

244,36

100

Formula I 1kg NPK/ clump/ year Formula II 2kg NPK/ clump/ year Formula III 3kg NPK/ clump/ year Fertilizer application formulae all give productivity 2 to 2.5 times more than formula without fertilizer application. 3.6. Effect of fertilizer application on ratio of shoots that develop into culms

Unit Formula Observed results Total shoots produced Total shoot harvested Total weight Total dying shoots Total shoots developing into culms

Control I

II

III

Shoot

4026

3574

4106

3300

Shoot

2246

2380

2672

2220

Kg Shoot

1308 666

1238 334

1460 580

1232 846

tree

1114

62%

860

59%

854

59%

234

21%

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With 4 -5 year old platation the weight of shoots obtained is 1.2 - 1.4 tonnes/ ha With the plants in the control formula: high ratio of dying shoots, ratio of shoots developing into culms is very low (21%) while ratios of shoots developing into culms are: formula I: 62%, formuala II: 72%, formula III: 59%

3.7. Effect of fertilizer application on yield of Dendrocalamus sp. shoots (per hectare)

Formula Observed results Total shoots produced Total shoot harvested Total weight % as compared with control

Unit

I

II

III

Control

Shoot

2700

3158

3416

1600

Shoot

1374

1800

2040

1350

Kg Shoot

824 188%

1044 238%

1108 252%

438 100%

With Dendrocalamus sp. plantation, the effect of fertilizer on yield per hectare is very clear Productivity of fertilizer application formulae as compared with control: I: 188%; II: 238%; III: 252%. Mean weight of a shoot between formulae is also different: control 0.32kg/shoot, formula I: 0.59kg/ shoot; II: 0.58kg/ shoot; III: 0.54kg/ shoot. Thus, bamboo planting for culms or shoots if high productivity is to be attained, intensive management is a must and yield of shoots can bedoubled and the number of shoots developing into culm can be 5- time increased as compared with control. Digging up the rhizomes of ten bamboo plants reveals the effect of shoots harvesting on shoots production of plants. The harvesting has stimulated 100% of the dormant scions to develop into shoots excluding those attacked by insects or rotten (7% of all the scions).

1 2 3 4 5 6 7 8 9 10 Total

Total number of scions on rhizome 5 6 7 6 6 5 6 5 7 4 57

Number of scions developing into shoots 5 5 6 6 6 5 5 5 6 4 53( 93%)

Scions that do develop into shoots 0 1 1 0 0 0 1 0 1 0 4( 7%)

not

3.8. Content of some nutrients in bamboo shoots of some bamboo species Content of some main nutrients (% of dry matter)

Species

D. mambranaceus Dendrocalamus sp Tre tµu M¹nh t«ng

Total sugars (%) 20,70 25,50 24,30 32,50

Total N (%)

Protein (%)

Amine acid

Xellulose

Vitamin C

3,10 3,80 3,60 3,80

19,37 23,75 22,50 23,75

2,10 2,60 2,40 2,60

28,00 21,00 20,00 23,00

167,20 105,60 154,00 96,80

Thus Dendrocalamus sp is also a bamboo species the nutrients content of its shoot is rather high. It can be classified as a bamboo species planted for shoots production.

IV. Conclusions and discussion -

Dendrocalamus membranaceus and Dendrocalamus sp. are all fast growing species, shoots serve as a delicious food stuff, shoots yield is over 1 tonnes/ ha/ year at the third year after planting and onwards.

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These two bamboo species can be propagated by branch layering with polythene wrapping. The surface of the planting hole over 1m x 1m in size gives a productivity twice the normal one. Amount of fertilizer applied: N 2.9kg, P 2kg, decomposed farm manure 25.5kg/ clump/ year (divided into 6 times ayear). Tool for shoot harvesting must be sharp, the shoot must be cut close to the rhizome. Height of harvested shoots is from 20 to 30cm.

References:

1. 2. 3. 4. 5. 6. 7. 8. 9.

Classification of bamboos according to morphological characteristics by Tran Dinh Dai (1967). Planting technique for Dendrocalamus sp. In Cau Hai by Nguyen Thi Phi Anh (1967). Effect of pure bamboo planting on soil fertility by Hoang Xuan Ty (1971). Characteristics of the soil under Dendrocalamus membranaceus by Nguyen Ngoc Binh (1963 – 1964). Research on planting technique for Dendrocalamus membranaceus in Thanh Hoa prov. By Phan Van Tich (1965 – 1968). Research on planting technique and management of Dendrocalamus membranaceus plantation by Tran Nguyen Giang and Luu Pham Hoanh (1976 – 1977). Bamboo cultivation by Ngo Quang De (1994). Research on acclimation of Dendrocalamus membranaceus from Thanh Hoa Prov. In Mid-region of North Vietnam by Le Quang Lien (1986 – 1990). Desmontration course document on planting technique for Dendrocalamus membranaceus by Le Quang Lien (1994).

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