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Agricultural residues and household energy


Table of Contents

[top] [end]What are agriculture residues?

Agriculture residues directly burnt as fuel in developing world include crop residues, forest litter, and also grass and animal garbage. Crop residues are more widely burnt than animal waste and forest litter.

Crop residues encompasses all agricultural wastes such as straw, stem, stalk, leaves, husk, shell, peel, lint, stones, pulp, stubble, etc. which come from cereals (rice, wheat, maize or corn, sorghum, barley, millet), cotton, groundnut, jute, legumes (tomato, bean, soy) coffee, cacao, olive, tea, fruits (banana, mango, coco, cashew) and palm oil.
Eucalyptus Litter
Eucalyptus Litter


Crops Crop wastes Residues production
Rice Straw, husk, bran 1.5t of straw and 0.2t of husk from 1t of rice
Wheat Straw, husk, bran 2t of residues from 1t of wheat seed
Maize Stalk, leaves 6t of waste from 1t of maize (leaves + stalks 4t)
Sorghum Straw, bran 2.5t of residues from 1t of sorghum seed
Barley Straw, bran 1.5t of straw from 1t of barley
Millet Straw, bran 2t of residue from 1t of millet produced
Cotton Stalk, lint, hull 0.2t of waste from 1t of cotton seed
Groundnut Shell, stalk, leaves 25% of shell weight from non husked
Jute Stem na
Tomato Stem na
Coffee Pulp, husk 3.6t of waste from 1t of green coffee
Olive na
Banana na
Coco Hull, fibre 0.9t of waste from 1t of coconut
Palm oil Shell, fibre, fruit bunches 75% waste from weight of fruit bunch
Mango Peel

Sources: (1) Memento de l’agronome : quatrième edition 1640 pages (2) J lamptey and al – 1990- bioenergy – IDRC/UNU - 210 page (3) CowiConsult – 1984 – Etude d’une utilisation efficace des déchets agricoles comme fuel domestiques au Sénégal 250 pages

Forest litter is mainly constituted of dry fallen leaves. Plantations of those species widely used for reforestation or soil conservation/sand fixation such as Eucalyptus and Casuarina equisetifolia, provide an important biomass litter yearly.
Eucalyptus Litter
Eucalyptus Litter
Animal garbage is livestock manure. Generally dry animal wastes directly used as fuel are cow and camel dung, and sometimes that of horse and sheep. The quantity of manure produced depends on the amount of fodder eaten, the quality of fodder and the liveweight of the animal. The excrement-yield values vary among the species.

SPECIES Daily manure yield as % of liveweight Animal liveweight (Kg) Animal liveweight (Kg) Dung yield (Kg/day) Dung yield (Kg/day)
Cattle 5 135 800 6.8 40.0
Buffalo 5 340 420 17.0 21.0
Pigs 2 30 75 0.6 1.5
Sheep/goats 3 30 100 0.9 3.0
Chickens 4.5 1.5 3 0.1 0.1

Source: (1) Memento de l’agronome : quatrième edition (2) GTZ – 1989 – biogas plants in animal husbandry – 134 pages
Filao Litter
Filao Litter


[top] [end]Agricultural residues characteristics

In the developing world, most agricultural residues burnt as fuel are used in their natural state with some pre-treatment like drying, and cutting, and compacting in rare occasions. Crop residues are characterized by its seasonal availability and have characteristics that differ from other solid fuels such as wood, charcoal, char briquette. The main differences are the high content of volatile matter and lower density and burning time.

Agricultural residues Volatiles (%) Fixed carbon (%) Ash (%) HHV (Kj/kg) LHV (Kj/kg) Density (%)
Arhar stalk 83.47 14.76 1.77 15.00 14.85
Bagasse 75.10 16.87 8.03 19.50 19.37 40 - 60
Bamboo dust 75.32 15.59 9.09 16.02 15.87
Cotton stalk 70.89 22.43 6.68 18.26 17.85 10 - 20
Coconut coir 70.30 26.77 2.93 18.20 17.79 7 - 8
Corn cob 80.20 16.20 3.60 15.58 15.23 10 - 20
Dhaincha stalk 80.32 17.01 2.67 19.63 19.43
Groundnut shell 68.12 24.97 6.91 17.20 17.06
Jute stick 75.33 19.00 5.67 19.45 19.01
Mustard shell 70.09 14.48 15.43 17.61 17.47
Pine needle 72.38 26.12 1.50 20.12 19.97
Rice husk 60.64 19.90 19.48 13.38 13.24 9
Sal seed leaves 60.03 20.22 19.75 18.57 18.42
Sal seed husk 62.54 28.06 9.40 20.60 20.13
Coffee husk 16.00 10



Concerning animal waste, the calorific values of cow dung and chicken droppings are respectively 16 – 19 Mj/kg and 14 - 16 Mj/kg. Cow dung calorific value is more important than the one of wood.
Filao Litter
Filao Litter
The large potentials of agro-industrial residues like bagasse, groundnut shell, palm oil residues are mainly used to meet the energy need of the factories.

[top] [end]Who uses them?

The rural families in the villages who own agricultural land use their own agricultural residues which varies throughout the year as per the crop planted. They use it as a household fuel for cooking, heating water and for space heating in colder climates.

Agricultural wastes are directly burnt to meet the need of cooking. Crop residues are yet used to light wood and charcoal.

West African potters burn a large amount of agricultural residues in their traditional pottery pit in order to produce their canaris, earthenware jars, ceramic stoves and other pottery.

In the part of the world faced by the scarcity of woodfuel and the cost-effective fuel substitutes, agricultural waste (owing to its high potentiality) may play a major role on sustainable energy. However the traditional use of crop residues and the lack of information on modern technologies such as briquetting, pelleting, and bioconversion, limit the development of large scale use which leads to increase the value of agricultural output.

Agriculture as a biomass supplier is yet affected by soil quality. Agricultural wastes can be used as either fuel or fertilizer. So the bio digestion of agricultural residues leads to provide both energy (biogas) and upgraded fertilizer than raw waste.

[top] [end]Agricultural residues potentiality in developing world

Agricultural wastes potentiality can be estimated by the following formulae:
Formula to estimate agricultural wastes
Formula to estimate agricultural wastes
Where:
Eucalyptus Litter means the potentiality of crop residues where “a” represents the crop production; “b” designs the crop residue yield production, and “i” the type of crop. when the calorific value of each type of crop is used the potentiality can be calculated in TOE (ton crude oil equivalent).

Eucalyptus Litter means the potentiality manure production where “alpha” represents the number of animal head; “b” designs the garbage yield production, and “i” the animal species.

Filao Litter means the potentiality of crop residues where “S” represents the area of plantation; “R” designs the residue yield production per unit of surface, and “i” the type of crop.

The statistical data about agricultures production are available for any country in the FAO website.

Example: the Senegal crop residues production
Crop productions

CROP

CROP PRODUCTION
( tonnes ) 1999

CROP PRODUCTION
( tonnes ) 2000

CROP PRODUCTION
( tonnes ) 2001

CROP PRODUCTION
( tonnes ) 2002

CROP PRODUCTION
( tonnes ) 2003

CROP PRODUCTION
( tonnes ) annual production

Groundnut

1 014 250

1 061 540

943 837

501 298

900 000

884 185

Sugarcane

889000

850000

890000

890000

890000

881 800

Oil palm

64000

65000

65000

65000

70000

65 800

Cotton

14 649

20 411

34 237

33 913

34 000

27 442

Millet

675000

600221

470105

414687

450000

522 003

Maize

66132

78593

106444

97858

103000

90 405

Sorgho

147444

143750

140297

143892

154000

145 877

Rice

239 786

202 293

243 907

177 756

177 756

208 300

Coco

4 700

4 700

4 700

4 700

4 700

4 700

Crop residues productions
Crop Residues Calorific value (KJ/Kg) Annual crop production (tonnes) Waste yield (%) Annual residues production (tonnes) Energy (TOE)
Groundnut Shell 17 884185 25.0% 221 046 89.5
Sugarcane Bagasse 19.37 881800 30.0% 264 540 122.0
Oil palm Wastes 16 65800 72.5% 47 705 18.2
Cotton Stem 18.3 27442 20.0% 5 488 2.4
Millet Wastes 18 522002.6 200.0% 1 044 005 447.4
Maize Wastes 18 90405.4 600.0% 542 432 232.5
Sorghum Wastes 18 145876.6 250.0% 364 692 156.3
Rice Wastes 12 208299.6 170.0% 354 109 101.2
Coco Wastes 17.9 4700 87.0% 4 089 1.7
TOTAL 2830511.2 2 848 107 1171.2

In Senegal the total of annual crop wastes equals 2 848 107 tonnes or 1171.2 TOE, which represents the amount of imported oil consumed. However the quantity available and exploited is low, under 40%. Bagasse and groundnut shell are widely burnt by industries to meet their energy need in the factories.

[top] [end]Advantages

  • Agricultural residue is a fuel which is available free of cost to the poor rural families.
  • It is also a useful way to dispose of the crop residues in the field, instead of burning them in situ.
  • Agricultural wastes remain safer than LPG which poses some safety concerns in local transport and use;
  • It is easy to handle and transport;
  • Low impact on women’s time for harvesting
  • Agricultural wastes are much easier to light than wood and charcoal.

[top] [end]Disadvantages

  • It is responsible for extreme cases of air pollution when it is burned in open fires or traditional or Improved stoves.
  • It is very bulky and has to be carried to the homes.
  • The seasonal availability of crop residues can be limit for its use.
  • Its burning time is worse.
  • Its storage requires more space in house.

[top] [end]Devices


Although the world rice production is important, particularly in developing countries, where it is cropped by family exploitation, its residue is widely used as fuel for cooking. In countries where rice production is important, such as Thailand and the Philippines, improved cooking stoves are made.

Improved cooking stoves used in Thailand : the Meechai, improved rice-husk stove without chimney.
The Meechai
The Meechai
The Meechai
The Meechai
The Meechai
The Meechai


The mayon turbo stove disseminated by REAP Canada
Mayon turbo stove (Photo: REAP Canada)
Mayon turbo stove (Photo: REAP Canada)
Mayon turbo stove (Diagram: REAP Canada)
Mayon turbo stove (Diagram: REAP Canada)


[top] [end]External links and references

http://www.ashdenawards.org/winners/mrhp
http://www.reap-canada.com

[top] [end]Contributors

User:Grant Ballard-Tremeer 1 September 2003
User:Dr Karabi Dutta 11 September 2003
User: Mamadou Fall 12 July 2007

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Page created: 01 September 2003; Last edited: 22 August 2007; Version: 7
Knowledge Bank text is available under the terms of the GNU Free Documentation License.

Pagename: AgriculturalResidues @HEDON: KCAA