1.2 Coordonnées des personnes-ressources et des institutions impliquées dans l'évaluation et la documentation de la Technologie

Nom du ou des institutions qui ont facilité la documentation/ l'évaluation de la Technologie (si pertinent)

Society for Community Development in Cambodia (SOFDEC) - Cambodge

Nom du ou des institutions qui ont facilité la documentation/ l'évaluation de la Technologie (si pertinent)

Local Agricultural Research and Extension Centre (LAREC) - Cambodge

1.3 Conditions relatives à l'utilisation par WOCAT des données documentées

Quand les données ont-elles été compilées (sur le terrain)?

05/08/2014

Le compilateur et la(les) personne(s) ressource(s) acceptent les conditions relatives à l'utilisation par WOCAT des données documentées:

Oui

1.4 Déclaration sur la durabilité de la Technologie décrite

Est-ce que la Technologie décrite ici pose problème par rapport à la dégradation des terres, de telle sorte qu'elle ne peut pas être déclarée comme étant une technologie de gestion durable des terres?

Non

2.1 Courte description de la Technologie

Définition de la Technologie:

Small-scale biogas systems fed with cow manure and water are implemented in order to supply the household with energy for cooking and lighting, as well as to produce fertilizer.

2.2 Description détaillée de la Technologie

Description:

In this case-study, a small-scale biogas system was introduced in order to generate both energy for home consumption and fertilizer. Small-scale biogas systems are implemented in different parts of the world, however the layout thereof varies considerably.
The model used in this case-study consists of different components (cf. technical drawing). First, there is an inlet where the land user puts cow manure mixed with water. On the bottom of the inlet, there is a board which closes the access to the bio-digester situated beneath the inlet. The board can be opened manually by pulling a string. Once the board is open, the fluid components go through a pipe which leads to the bio-digester. In the bio-digester, bacteria transform the organic matter into biogas (mainly methane and CO2) and slurry. At the other end of the digester, there is another pipe (outlet). The outlet is lower than the inlet, and due to the difference in pressure, the slurry is pushed out of the digester. The slurry is dried and applied to the fields two to three times a year with the help of an ox cart. It has similar effects on the plant growth as chemical fertilizer as it does not build up the soil organic matter as much as compost. The biogas, however, is pushed to the pipe situated on top of the digester and can be utilized for domestic uses. The gas is used for cooking and lighting.

The use of biogas allows reducing the expenses on charging batteries for the lighting, as well as reducing the firewood use (usually from deforestation) for cooking. The slurry reduces the expenses on chemical fertilizer in the fields and has the advantage of killing the weed and rice seeds present in the manure and crop residues.

For building the biogas system, there is governmental and NGO support. These two actors finance half of the construction costs. The other half is paid by the land user. Building a biogas system is quite costly, with about 400 $, and not all of the land users in the area can afford paying 50% of its price. However, the costs borne by the land user are paid off within a few years due to reduced expenses on firewood, chemical fertilizer, and charging batteries. The construction itself was undertaken by local companies.
The costs are paid off within a few years due to the reduced expenses on firewood, chemical fertilizer and battery charging.

The analysed area is flat (slope < 2%), tropic (dry and wet season), and the soils are mostly sandy or loamy. The soils contain little organic matter (low soil fertility, acidification, small amount of cattle, area has been deforested a long time ago) and the groundwater table is rather high (1-3 m during the dry season, on the surface during wet season).
Due to climate change, the rainfalls are more erratic, temperatures rise and droughts are more recurrent. Rice is the predominant crop grown in the area, since it serves as staple food (mix subsistence and commercial activities). Rice is often grown in monocultures and harvested once a year. Once the rice is harvested (dry season), the cattle are released to the paddy fields. The cattle is often replaced by hand tractors, which effects the production of manure but allows a higher amount of crop residues on the fields.
As an addition to rice, most land users grow vegetable and fruits in small home gardens (subsistence) and complement their income by producing handicrafts or through off farm income / remittances from family members working in other places. The increasing migration rate (the young generation leaves the villages to work in the cities, garment industry or abroad) results in a decrease of available labour force in the area which has detrimental effects on the agricultural activities. Furthermore, the civil war in the 1970s (Khmer Rouge) led to the loss of agricultural knowledge which different NGOs try to re-establish.

2.3 Photos de la Technologie

2.5 Pays/ région/ lieux où la Technologie a été appliquée et qui sont couverts par cette évaluation

2.6 Date de mise en œuvre de la Technologie

Si l'année précise est inconnue, indiquez la date approximative: :

• il y a moins de 10 ans (récemment)

2.7 Introduction de la Technologie

Spécifiez comment la Technologie a été introduite: :

• par le biais de projets/ d'interventions extérieures

Commentaires (type de projet, etc.) :

LWS (a Dutch NGO) in joint efforts with specialists from the National Biodigester Program NBP. Implementation in 2012

3.1 Principal(aux) objectif(s) de la Technologie

• améliorer la production
• créer un impact économique positif

3.2 Type(s) actuel(s) d'utilisation des terres, là où la Technologie est appliquée

Commentaires:

Major land use problems (compiler’s opinion): Lack of organic matter, lack of water retention in soil, irregularity of rainfall, low soil fertility (sandy soil), monocultures, bare soil during dry season, ploughing.
Major land use problems (land users’ perception): Low soil fertility, lack of water.
Livestock is grazing on crop residues
Constraints of settlement / urban
Constraints of infrastructure network (roads, railways, pipe lines, power lines)

3.3 Informations complémentaires sur l'utilisation des terres

Nombre de période de croissance par an: :

• 1

Précisez:

Longest growing period in days: 210, Longest growing period from month to month: June-December

3.4 Groupe de GDT auquel appartient la Technologie

• technologies d'efficacité énergétique

3.5 Diffusion de la Technologie

Spécifiez la diffusion de la Technologie:

• répartie uniformément sur une zone

Si la Technologie est uniformément répartie sur une zone, indiquez la superficie couverte approximative:

• 0,1-1 km2

Commentaires:

There are only 4 households in this village which apply the technology (lack of money and/or cattle). However, similar Technologies are introduced in other provinces – yet it is difficult to estimate the area covered. Estimation for this village.

3.6 Mesures de GDT constituant la Technologie

Commentaires:

Main measures: management measures
Secondary measures: structural measures

3.7 Principaux types de dégradation des terres traités par la Technologie

Commentaires:

Main causes of degradation: soil management (Ploughing, soil is left bare for several weeks), crop management (annual, perennial, tree/shrub) (Rice monoculture (rice as staple crop)), change of seasonal rainfall (More erratic beginning of wet season), droughts (On dry soil, rice cannot be planted and if already planted, rice cannot grow), labour availability (High migration rates from the villages to garment industry, cities or abroad, influence agricultural activities (e.g. broadcasting instead of transplanting of rice seedlings)), education, access to knowledge and support services (Khmer Rouge regime in the 1970s, a lot of knowledge got lost)
Secondary causes of degradation: over-exploitation of vegetation for domestic use (Rice straw is removed for different domestic uses (cattle, mushroom cultivation, etc.)), overgrazing (Cattle eats rice straw left after harvest, less organic matter on the field, grazing is not managed), change in temperature (More hot days), Heavy / extreme rainfall (intensity/amounts), land tenure (Some incidents of land grabbing, land use rights not clear, corruption), poverty / wealth

3.8 Prévention, réduction de la dégradation ou réhabilitation des terres dégradées

Spécifiez l'objectif de la Technologie au regard de la dégradation des terres:

• prévenir la dégradation des terres
• réduire la dégradation des terres

4.1 Dessin technique de la Technologie

4.2 Spécification/ explications techniques du dessin technique

Biodigester. Inlet: top left; gas outlet: top centre; digestion chambre: centre; and outlet: right. For the comlete building instructions contact the NBP.
Technical knowledge required for field staff / advisors: high (The most challenging part is the construction of the construction of the Biodigester.)
Technical knowledge required for land users: low
Main technical functions: increase in nutrient availability (supply, recycling,…)
Secondary technical functions: increase in organic matter

Structural measure: Biodigester. Round shape. Tiles and concrete.
Width of ditches/pits/dams (m): 4 m^3
Structural measure: Connecting pipes made of plastic
Construction material (concrete): Tiles are covered in concrete.
Construction material (other): The most challenging part is the construction of the Biodigester.
Other type of management: Change of energy supply system for home consumption.

4.3 Informations générales sur le calcul des intrants et des coûts

autre/ monnaie nationale (précisez):

Riel

Indiquer le taux de change du dollars en monnaie locale (si pertinent): 1 USD= :

4000,0

4.4 Activités de mise en place/ d'établissement

	Activité	Type de mesures	Calendrier
1.	Construction of the biodigester by external experts. The land user did not help with the construction, he only paid 200 US$. The other 200 US$ were paid by the National Biodigester Program.	Structurel	Dry season, when water table is low.

4.5 Coûts et intrants nécessaires à la mise en place

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Matériaux de construction	Construction of biodigester		1,0	400,0	400,0	50,0
Coût total de mise en place de la Technologie					400,0

4.6 Activités d'entretien/ récurrentes

	Activité	Type de mesures	Calendrier/ fréquence
1.	Add manure and water to the inlet	Modes de gestion	once per day all year round
2.	Collect residuals from biodigester, spread it out and let it dry, and finally put it on the field.	Modes de gestion	3 times/year

4.7 Coûts et intrants nécessaires aux activités d'entretien/ récurrentes (par an)

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Main d'œuvre	Labour		1,0	121,5	121,5	100,0
Coût total d'entretien de la Technologie					121,5

Commentaires:

Machinery/ tools: Cart to bring residues from the biodigester onto the fields.

The costs were calculated for 1 biodigester with a capacity of 4 m3.

4.8 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

The most costly part of this Technology is the construction of the biodigester. Once the system is installed, the costs borne by the land user are low. Also, the land user can save money since he doesn’t need to buy firewood any more.

5.1 Climat

5.2 Topographie

5.3 Sols

5.4 Disponibilité et qualité de l'eau

Commentaires et précisions supplémentaires sur la qualité et la quantité d'eau:

Ground water tabel and availability of surface water data during dry seasons. People use water for drinking after filtering or boiling.

5.5 Biodiversité

Commentaires et précisions supplémentaires sur la biodiversité:

Only degraded forests are in the area.

5.6 Caractéristiques des exploitants des terres appliquant la Technologie

Indiquez toute autre caractéristique pertinente des exploitants des terres:

Land users applying the Technology are mainly Leaders / privileged
Population density: 10-50 persons/km2
Annual population growth: 0.5% - 1%
Off-farm income specification: Handicraft, remittances and factory work.

5.7 Superficie moyenne des terres détenues ou louées par les exploitants appliquant la Technologie

5.8 Propriété foncière, droits d’utilisation des terres et de l'eau

Propriété foncière:

• communauté/ village
• individu, sans titre de propriété

Droits d’utilisation des terres:

• communautaire (organisé)
• individuel

Droits d’utilisation de l’eau:

• accès libre (non organisé)

Commentaires:

Land ownership is very complex. Most of the land belongs officially to the government, yet many land users hold a paper confirming they applied for a land title – but de iure, this paper is worthless.

5.9 Accès aux services et aux infrastructures

6.1 Impacts sur site que la Technologie a montrés

Impacts socio-économiques

Production

Revenus et coûts

Impacts socioculturels

Impacts écologiques

Cycle de l'eau/ ruissellement

Sols

Autres impacts écologiques

6.2 Impacts hors site que la Technologie a montrés

6.3 Exposition et sensibilité de la Technologie aux changements progressifs et aux évènements extrêmes/catastrophes liés au climat (telles que perçues par les exploitants des terres)

Changements climatiques progressifs

Changements climatiques progressifs

	Saison	Type de changements/ extrêmes climatiques	Comment la Technologie fait-elle face à cela?
températures annuelles		augmente	bien

Extrêmes climatiques (catastrophes)

Catastrophes météorologiques

	Comment la Technologie fait-elle face à cela?
pluie torrentielle locale	bien
tempête de vent locale	bien

Catastrophes climatiques

	Comment la Technologie fait-elle face à cela?
sécheresse	bien

Catastrophes hydrologiques

	Comment la Technologie fait-elle face à cela?
inondation générale (rivière)	pas bien

Autres conséquences liées au climat

Autres conséquences liées au climat

	Comment la Technologie fait-elle face à cela?
réduction de la période de croissance	bien

6.4 Analyse coûts-bénéfices

Quels sont les bénéfices comparativement aux coûts de mise en place (du point de vue des exploitants des terres)?

Quels sont les bénéfices comparativement aux coûts d'entretien récurrents (du point de vue des exploitants des terres)?

6.5 Adoption de la Technologie

• plus de 50%

Si disponible, quantifiez (nombre de ménages et/ou superficie couverte):

100% or 4 land user families

Commentaires:

100% of land user families have adopted the Technology with external material support
4 land user families have adopted the Technology with external material support
The farmers can ask the National Biodigester Program for subsidies, but need to pay half of it on their own. As the farmers often lack money and need at least 3 - 4 heads of cattle to produce enough manure while they switch more and more to hand tractors, not many farmers are building new biogas digesters.

6.7 Points forts/ avantages/ possibilités de la Technologie

Points forts/ avantages/ possibilités du point de vue de l'exploitant des terres
Fertilizer production (sludge).
Saves money and time on the cooking fuel (previously wood) and electricity (charging batteries) for the light.
No weed seeds in the sludge compared to compost and raw manure if used as fertilizer.

Points forts/ avantages/ possibilités du point de vue du compilateur ou d'une autre personne ressource clé
Less deforestation for firewood.

6.8 Faiblesses/ inconvénients/ risques de la Technologie et moyens de les surmonter

Faiblesses/ inconvénients/ risques du point de vue de l’exploitant des terres	Comment peuvent-ils être surmontés?
The residue does not improve the soil as much as compost.	Make compost in addition to biogas to enhance the soil organic matter.
The building costs are prohibitive	Increase subsidies from state or NGOs.
At least 3-4 heads of cattle or 4-5 pigs have to be kept to produce enough manure.	Diversify production with different animals.
Work has to be done each day to produce biogas.

Faiblesses/ inconvénients/ risques du point de vue du compilateur ou d'une autre personne ressource clé	Comment peuvent-ils être surmontés?
Overgrazing could become a problem as more cattle needs to be kept.	Add slurry as a liquid fertilizer
Part of nitrogen is volatilized during the drying of the sludge.

7.1 Méthodes/ sources d'information

7.2 Références des publications disponibles

Titre, auteur, année, ISBN:

NBP National Biodigester Program

Disponible à partir d'où? Coût?

www.nbp.org.kh

Titre, auteur, année, ISBN:

Lam et al. 2009. Domestic Biogas Compact Course. University of Oldenburg.

Disponible à partir d'où? Coût?

http://www.nbp.org.kh/publication/study_report/2_domestic_biogas%20.pdf

Titre, auteur, année, ISBN:

Gurung. 2009. Review of Literature on Effects of Slurry Use on Crop production. The Biogas Support Program