BIOMASS AND ENERGY POTENTIALS OF SELECTED AGRICULTURAL CROPS : www.reein.org

BIOMASS AND ENERGY POTENTIALS OF SELECTED AGRICULTURAL CROPS

M A Zaman

Professor

Department of Farm Power and Machinery

Bangladesh Agricultural University

Mymensingh 2202, Bangladesh

E-mail: zamanma_bd@yahoo.com

· A huge number of trees or plant species and crop varieties, grown in Bangladesh, produces tonnes of biomass.

· Biomass is the only source of fuel for cooking in rural areas.

· ESCAP (1989) reported that biomass in Bangladesh is generally used as food, feed, fodder, organic manure and building materials and as the raw materials for cottage industries including ploughs, fishing equipment, bullock carts and country boats.

· Some crop residues play vital role as a source of energy for industrial use.

· In rice mills, rice husk is used as heat source for mechanical drying of parboiled paddy and for generating steam for parboiling. Rice husk is also used in ‘chira’ and ‘muri’ mills.

· Bagasse obtained from sugarcane is used as heat source in sugar mills and gur making.

· The production and utilization of crop biomass and their preservation requires serious attention for energy use planning.

· Generation of information regarding the potential crop biomass is needed to assess the demand and supply of bioenergy for increasing population of the country.

· Researchers willing to work in the field of renewable energy should undertake research initiatives to explore the biomass and bioenergy potential of agricultural crops.

· The present study was done to estimate the biomass and bioenergy potentials of some selected crops such as paddy, wheat, mustard, jute, dhaincha, sugarcane and coconut.

METHODOLOGY

The estimation of crop biomass and bioenergy was based on :

q Secondary data (collected from research

publications)

q Interviewing the farmers to verify the

secondary data

q Experimental data (done by the author)

1st Phase of study Period : SEP/1999 – MAY2000

Survey work done at :

Ø Bamundia village of Dumuria Upazila of

Khulna district and

Ø Rogunathpur village of Moheshpur Upazila of

Jhenaidah district

The farmers were interviewed by the under-graduate students on the basis of a questionnaire.

2nd Phase Study Period : NOV/2000 – AUG2001

Amounts of biomasses from selected crops were determined experimentally.

Work done at

• BAU Farm for harvesting the crops and

• Labs of FPM and FT&RI departments of BAU for

drying and lab measurements

Crops selected for the study: Paddy, Wheat, Mustard, Jute, Dhaincha, Sugarcane and Coconut

Data required for estimation of crop biomass :

(a) Crop

(b) Area of harvested crop biomass (ha)

(d) Total dry weight of crop biomass (t) [ sum of (c) values]

(e) Relative proportion of the plant parts such as grains,

straw, husk, bran, leaves & twigs, stalk, fibre, etc.

expressed as ratio or in percent on dry weight basis

(f) Total cropped area of (a) in Bangladesh (ha)

Data estimated

(g) Rate of production of crop biomass (t/ha) [(d) / (b)]

(h) Annual production of crop biomass (t) [(f) x (g)]

Data required for estimation of bioenergy :

(a) Total yield of crop biomass (t/ha)

(b) Energy value of crop biomass (GJ/t)

(d) Annual production of crop biomass (t)

Data estimated

(e) Production of crop bioenergy (GJ/ha)

[ (a) x (b) ]

(f) Annual production of crop bioenergy (GJ)

[ (b) x (d) ] or [ (c) x (e) ]

The crop production data and the energy values of different crop biomasses (GJ/t) are taken from secondary sources as mentioned in the text.

RESULTS AND DISCUSSION

Biomass and Energy Potential

PADDY (ORYZA SATIVA)

Rice is grown in three different seasons such as Aus, Aman and Boro. Total rice production is 18.86 million tons from 10.27 million ha of land (1997-98 data; BBS, 1998).

The straw-grain ratio of rice was found experimentally as 1.69 (Table 2). Biswas and Khan (2000) reported a slightly lower value of 1.63.

Using these values, national production of rice biomass i.e. straw is estimated to be within 30.74 to 31.88 million tons (Table 3). The rice used for calculation of straw-grain ratio was T. Aman and variety Mukta. Moisture content level of the straw and grains could not be measured, but the straw and grains were adequately dried before experimentation.

According to Baqui (1997) total paddy biomass is consisted of 50% straw, 25% grains, 17% milled rice, 6% husk and 2% bran.

Considering the energy value of 16.74 GJ/t of paddy biomass (Eusuf et al., 1987), the availability of total bioenergy from paddy was estimated to be 1263.0 x 106 GJ.

Table 2 Experimentally found straw-grain ratio of paddy

	Rep 1 Average	Rep 2 Average	Rep 3 Average	Average of 3 Rep
Initial wt. of bundle (g)	1081	1400	1433
Weight of straw (g)	620	859	876
Weight of grains (g)	410	500	480
Straw/grain ratio	1.51	1.72	1.83	1.69
Each replication consisted of 5 experimental runs

Table 3 Production of biomass and bioenergy from paddy [based on data of Baqui (1997) and Eusuf et al. (1987)]

Paddy/Rice	Biomass production		Energy value	Total energy
	(million tonnes)	(% of total)	(GJ/t)	(x 106 GJ)
Straw	37.72	50	16.74	631.50
Paddy grains	18.86	25		315.75
Milled rice	12.83	17		214.71
Husk	4.53	6		75.78
Bran	1.51	2		25.26
Total	75.45	100		1263.00

WHEAT

Wheat production in 1998 was 1.803 million metric tonnes from 805 thousand ha of land.

Taking straw/grain ratio of 1.87 (Talukder and Shirazi, 1997), wheat biomass is estimated to be 5.175 million metric tonnes of which 65% is straw and 35% wheat grains (Table 4).

The amount of bioenergy is estimated as shown in Table 4

Table 4 Annual production of biomass and energy from wheat

Wheat	1998 data	Percent	Energy value	Total energy
	1998 data	Percent	(GJ/t)	(x 106 GJ)
Straw/grain ratio	1.87
Cropped area (x 1000 ha)	805
Wheat grains (x 1000 t)	1803	35	16.87	30.42
Wheat straw (x 1000 t)	3372	65		56.88
Total biomass (x 1000 t)	5175	100		87.30
Based on data of Talukder and Shirazi (1997) and Eusuf et al. (1987)

MUSTARD

The total area under mustard cultivation in Bangladesh 343.77 thousand ha and mustard seed production is 253.64 thousand tons (BBS, 1998).

Straw-grain ratio of mustard was found by experiment as 14.5. Based on the above figures, mustard straw biomass production is about 3678 thousand tons (Table 8).

Table 8 Composition, biomass and energy of mustard

Crop	Stem (g)	Seed (g)	Straw/grain ratio
Mustard	4677	322.5	14.5

䦋㌌㏒㧀좈໱琰茞ᓀ㵂Ü	Area (x 1000 ha)	Production (million tonnes)	Energy (GJ/t)	Total energy (million GJ)
Mustard	343.77
Grain (seed)		0.254	16.0	4.06
Straw		3.678		58.85
Total biomass		3.932		62.91

JUTE (CORCORUS CAPSULARIES)

Area under jute cultivation is 577.62 thousand ha and production is about 5.8241 million tonnes (BBS, 1998; 1997-98 data).

Jute biomass consists of about 26% fiber and 60% stalk and 14.0% leaves (Biswas and Khan, 2000). Using these data annual production of jute stalk and leaves in Bangladesh is estimated to be 13.28 and 3.09 million metric tonnes, respectively (Table 5 and 6).

Table 5 Jute Biomass

Jute	% of total biomass	% of fibre
Fibre	26.25	100.0
Stalk	59.84	228.0
Leaves	13.91	53.0
Total biomass	100.00
Stalk/fibre ratio = 2.28

Table 6 Production of biomass and bioenergy from jute

Jute	Annual production (million tonnes)	Energy value (GJ/t)	Total energy (x 106 GJ)
Jute area (x 1000 ha)	577.62
Fibre	5.824	19.62	114.27
Stalk	13.277		260.49
Leaves	3.086		60.55

DHAINCHA (SESBANIA ROSTRATA)

National level of production and area under this crop are not available. The amount of biomass obtainable from dhaincha has been found experimentally as shown in Table 7.

Total yield of green biomass of African dhaincha is about 48.3 t/ha.

Thirty farmers of three villages near Bangladesh Agricultural University campus of Mymensingh were interviewed for the use of dhaincha. All of the farmers use dhaincha primarily as fire wood and for fencing.

Karim (1988) experimented on the biomass and energy production of dhaincha as affected by plant density.

Production of green biomass of dhaincha ranged from 37.53 to 41 t/ha.

The drymatter yield of dhaincha ranged from 8.77 to 9.01 t/ha.

Table 7 Biomass yield of dhaincha (experimental result)

䦋㌌㏒㧀좈໱琰茞ᓀ㵂Ü	Plot 1	Plot 2	Plot 3	Average
Area (m2)	3 x 3	3 x 3	3 x 3	3 x 3
No. of plants	132	140	125	132.3
Max. height (m)	4.5	4.0	3.8	4.1
Min. height (m)	2.0	2.3	1.8	2.0
Stem weight (kg)	42.37	44.94	40.13	42.50
Seed weight (kg)	0.952	1.05	0.996	1.00
Total weight (kg)	43.32	45.97	41.12	43.50
Yield of green biomass (t/ha)				48.3
Yield of drymatter (t/ha)				30.2

SUGARCANE

Bagasse obtained from sugarcane is used as energy source in sugar mills in the production process of sugar. The surplus residues left over in these mills would be available for alternative use.

The composition of sugarcane biomass, biomass production and energy obtainable from sugarcane are shown in Table 9.

Leaves and tops (43%) are trimmed off. Trimmed cane produces 8.13% sugar, 36% bagasse, 3.72% molasses, 3.59% filtercake and 48.5% water.

Table 9 Production of sugarcane biomass and energy

䦋㌌㏒㧀좈໱琰茞ᓀ㵂Ü	Biomass (million tonnes)	Energy value (GJ/t)	Total energy (million GJ)
Cane	7.39	10.0	73.84
Leaves & tops	3.18	14.4	45.78
Trimmed cane	4.21
Bagasse	1.52	15.9	24.12
Molasses	0.157	25.1	3.94
Filtercake	0.151
Sugar	0.342
Alcohol	224 L/t molasses
Based on data of Iqbal et al. (1994)

Coconut (Cocos Nucifera)

Coconut trees has a versatile use so it is called ‘Trees of Heaven”. Every part of this tree and its fruits are useful and it is a great source of biomass. Coastal areas are very much suitable to grow coconut. Barisal, Noakhali, khulna are the major areas for production of coconut. It is also cultivated more or less in all areas of Bangladesh.

Coconut is cultivated in 32,335 ha of land and annual production is 86,000 tonnes (Mondal, 1990).

Coconut fruit has four parts such as husk or fibre, shell, meat and water. Their proportion was experimentally found as 31% fibre, 24.4% shell, 21.5% meat and 23.1% water (Table 10).

Annual production of coconut fibre, shell and meat are 27.72, 21.75 and 19.22 thousand tonnes respectively (Table 11).

Table 10 Biomass of coconut fruit

Coconut	% of total	Moisture content (% w.b.)
Husk or fibre	31.04	10.71
Shell	24.35	䦋㌌㏒㧀좈໱琰茞ᓀ㵂Ü
Meat	21.52	36.03
Water	23.08	䦋㌌㏒㧀좈໱琰茞ᓀ㵂Ü
Total	100.0	䦋㌌㏒㧀좈໱琰茞ᓀ㵂Ü

Table 11 Estimation of coconut biomass (from experimental data)

Coconut	Total biomass (x 1000 t)	Energy value (GJ/t)	Total energy (x 1000 GJ)
Husk or fibre	27.72	14.5	401.94
Shell	21.75	15.0	326.25
Meat	19.22	16.0	307.52
Total	89.32		1035.71

UTILIZATION OF CROP BIOMASS

Uses of rice straw

Feed for cattles
Fuel for cooking and parboiling paddy
Thatching of roofs
Fencing
Mulching

Probable Industrial Uses

Paper pulp (Baqui, 1997)
Hard corrugated mediums (Baqui, 1997)
Highly reactive silica for concrete block and fireboards (Baqui, 1997)

Use of rice husk

• Fuel for parboiling and drying paddy in rice mills

• Fuel for cooking and parboiling paddy at homes

• Poultry litter

• Soil conditioner

• Briquettes

Probable Industrial Uses

• Packing and abrasive material

• Admixture in building materials

• Glues, absorbent and soot

• Silica for solar cells

• Highly reactive silica for concrete block and fireboards (Baqui, 1997)

Uses of wheat straw

Feed for cattles
Fuel for cooking and parboiling paddy
Thatching of roofs
Fencing
Mulching

Use of oilseed biomass

Oilseed Grains

Food (oil) and animal feed (oilcake)
Medicinal oil

Oilseed Residues

Animal feed
Fuel for cooking (straw)
Composting of manure

Jute Stalk

– Fuel for cooking and heating at homes

– Roofing and Fencing

– Partex board, geo-textiles and paper pulp

Jute Fibre

– Ropes, gunny and shopping bags

– Handicrafts

Jute Leaves

– Food & feed

– Biofertilizer

– Rottening of Jute

Use of dhaincha biomass

Dhaincha Stalk

Fuel
Fencing and building materials

Dhaincha Leaves

Fuel
Animal feed
Biofertilizer

Dhaincha is a high biomass producing plant and used as green manure, fuel, animal feed, fencing and building materials.

Although dhaincha is a nitrogen-fixing plant, it also has preservative value in biotechnology (AIS, 2000).

Sugarcane Leaves & Tops

Animal feed
Fuel

Bagasse

Fuel for sugar processing in sugar mills
Can be used for paper pulp

Molasses

• Animal feed

• Extracting alcohol

Use of coconut biomass

Coconut Meat

Food
Cosmetic Oil
Preservatives
Animal feed (oilcake)

Coconut Shell

Making ‘Hookka’
Handicrafts

Coconut Fibre

• Making coir (Hossain & Zaman, 1996) and ropes

• Burnt for fumigation

Use of coconut biomass

The husk of coconut has industrial use such as mat, rope, foot mats (papos), and seats of local transports, etc. Shell of coconut is also used as solid fuel (Mondal, 1990).

More or less about 300 usage are identified in coconut biomass such as its husk is used as yearns, ropes, brushes, mattresses, mats and carpets, floor mats, foot mats, cushion, packing materials, insulating materials etc. shell is used as making coal, ‘hookka’, baby toys, carbon used in laboratories (Hossain and Zaman, 1996). Its leaves are used as roofing of sheds and local houses, fencing and mulching purpose. Coconut tree is also valuable and is used as beam in houses and as source of wood.

Use of biomass of pulses

Pulse Grains

• Food and animal feed

Pulse Residues

• Animal feed

• Fuel for cooking

Use of biomass of vegetables

Vegetables

Food
animal feed
Medicinal oil

Vegetable Residues

Composting of manure

RECOMMENDATIONS

More Research on

Biomass potentials
Potential Uses and applications
Conversion into briquettes
Gasification
Conservation of energy
Improved stoves/furnaces
Development of RE Technology

Exchange & Dissemination of

Information

IT linkage among Research Org.
Directory of Resource Personnel
Manpower development
Training of extension agents
Development of Information package
Effective channel for dissemination to farmers/end users
Extension through various medias

Policy Issues

Govt. policy needed for RE
Formulation of strategy and future plan
Mandates to relevant organizations
Funding
Undertaking projects on priority basis

Data collection on crop and plant biomass should be included in the census of agriculture.

Table A1 Energy values of some crop biomasses

Reference
Crop biomass	Energy value (GJ/t)	Reference
Rice	16.74	Eusuf et al. (1987)
Jute	19.62
Wheat	16.87
Dhaincha	19.28
Banana	15.79
Others	16.00
Crop biomass	Energy value (GJ/t)	Reference
Weeds	13.00	Hall et al. (1995) BBP & BBS (1989)
Animal excreta	14.00
Wood	15.00
Crop residues	13.00
Arhar	20.00
Jute stick	12.76
Crop biomass	Energy value (GJ/t)
Rice straw
12.24
Rice husk
12.76
Bagasse	14.50
Firewood	15.40
Twigs & leaves	15.40
Cowdung	8.75
Crop biomass	Energy value (GJ/t)	Reference
Sugar	0.0167	Iqbal et al. (1994)
Molasses	25.116
Bagasse	15.907
Cane leaves & tops	14.408