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)?

14/08/2014

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:

Rice husks as well as empty seeds are pyrolised and used as a soil amendment in the rice seed beds and the vegetable gardens.

2.2 Description détaillée de la Technologie

Description:

Biochar is the residue left after the pyrolysis of any organic matter and is used as a soil amendment. Pyrolysis occurs when the organic matter is heated in anaerobic conditions, which is usually done in specially designed kilns. Sometimes it is also made in a conventional fire, which is extinguished before the char turns to ash. Agricultural wastes like rice husks or unfilled grains are mainly used. Biochar can have many positive effects on the soil and plants:
-It buffers the pH, and has usually a high pH due to theash content.
-Due to its porous structure, it holds water and serves as refuge for microorganisms.
-It absorbs and adsorbs nutrients, both cations and anions. They are available for the plant roots.
-It can increase the resistance of plants to diseases.
Due to all these effects, the increased yields are higher than those that can be achieved only through the nutrients contained in the Biochar itself. Biochar is and was used in many parts of the world as soil amendment, with some benefits persisting for centuries. In Cambodia it was used during the Pol Pot regime to reduce the smell of the human faeces that were used on the fields due to a lack of other fertilizers. Today research in the Biochar domain is increasing, especially since the discovery of the man-made terra preta soils in South America.

Biochar is mainly used to increase the fertility, water holding capacity and carbon content of the soil. The fact that the benefits of Biochar addition to the soil remain for several years, unlike chemical fertilizers, makes it attractive to farmers. Other purposes, like the increased resistance of plants to diseases and buffering of nutrients are also of importance.

Biochar was introduced or reintroduced trough different NGOs, JICA (Japanese International Cooperation Agency) in this case study. Because of knowledge exchange between farmers, a rice husk char/ash mix, as residue from the pottery baking, was used already in 2011. In 2013 JICA borrowed a Biochar kiln to the local farmer self-help group with a training, so they could produce Biochar by themselves. The inner part of the kiln (cf. technical drawing) is filled with wood and lit. It is then put into an empty oil barrel, which is filled with rice husks. The heat pyrolyses the husks from the bottom to the top of the barrel, and the gases are burned in the inner part of the kiln and the chimney. Just before the upper part is pyrolysed, the husks are extinguished. There is a weight loss of about 50 to 60 % caused by this process. The Biochar is added to the fields after ploughing, and the fields are harrowed. In this case study, Biochar is used both in rice seed beds and in a vegetable patch. Concentrations of 0.5 kg/m2 are used in the rice seed bed, and 2.5 kg for the vegetables. Due to the little available quantities of husks, Biochar is not applied to the field yet. The use of Biochar is spreading quickly from farm to farm

The analysed area is flat (slope < 2%), with a tropical climate (dry season from November to May and wet season from June to October), and the soils are mostly sandy or loamy. The soil has a low fertility, contains little organic matter, and acidifies. The area has been deforested a long time ago, and the groundwater table is rather high (1-2 m during the dry season, on the surface during wet season).
Due to climate change, farmers notice more erratic rainfall, temperature rises and more recurrent droughts. Rice is the predominant crop grown in the area, since it serves as staple food (mix subsistence and commercial activities). Cattle are usually grazing on the fields after the harvest, without much control. Thus the cattle grazes too often and too much on the same spot, leading to degradation.
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. Several NGOs are trying to re-establish the knowledge.

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.) :

It was introduced in 2010 by JICA, the Japanese International Cooperation Agency.

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

• améliorer la production

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

Commentaires:

Major land use problems (compiler’s opinion): Soil fertility decline, water availability
Major land use problems (land users’ perception): Water availability. Interestingly the farmer says that soil fertility is not a problem, as the farmers know about the use of compost. The compost application is the problem.

3.3 Informations complémentaires sur l'utilisation des terres

Approvisionnement en eau des terres sur lesquelles est appliquée la Technologie:

• mixte: pluvial-irrigué

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

• gestion intégrée de la fertilité des sols

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:

Area unknown and rapidly spreading.

3.6 Mesures de GDT constituant la Technologie

3.7 Principaux types de dégradation des terres traités par la Technologie

Commentaires:

Main causes of degradation: soil management (Ploughing and bare soil during dry season.), labour availability (Farmers go to work in the garment industry, in construction, or sell their labor elsewhere.)
Secondary causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (Deforestation happened many years ago.), overgrazing (Uncontrolled grazing during dry season.), change in temperature (More hot days according to UNDP and farmers.)

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:

• réduire la dégradation des terres

4.1 Dessin technique de la Technologie

4.2 Spécification/ explications techniques du dessin technique

Biochar kiln. In the inner part, the combustion chamber, a wooden fire is lit. The burning chamber is then placed in the oil barrel, which is filled with rice husks. The heat pyrolyses the husks, the gas burn in the chamber and chimney. When pyrolysis is almost completed, the char is extinguished.
Kampong Chhnang
Date: 2014

Technical knowledge required for field staff / advisors: high
Technical knowledge required for land users: moderate (When farmers only buy Biochar the required technical knowledge is low.)
Main technical functions: increase in organic matter, increase in nutrient availability (supply, recycling,…)
Secondary technical functions: improvement of surface structure (crusting, sealing), improvement of topsoil structure (compaction)

Manure / compost / residues
Material/ species: Rice husk Biochar (together with compost, which he already did before)
Quantity/ density: 0.5-2.5
Remarks: Entity: kg/m^2. Distributing on fields and harrowing.

4.3 Informations générales sur le calcul des intrants et des coûts

autre/ monnaie nationale (précisez):

Riels

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.	biochar kiln

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
Equipements	kiln		1,0	50,0	50,0
Coût total de mise en place de la Technologie					50,0

4.6 Activités d'entretien/ récurrentes

	Activité	Type de mesures	Calendrier/ fréquence
1.	Biochar making	Agronomique	Whenever there is time
2.	Adding Biochar to the fields after the compost was plowed in, and harrowing.	Agronomique	Yearly, before planting.

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	20,0	20,0	100,0
Equipements	machine use		1,0	0,25	0,25	100,0
Matériel végétal	rise husks		1,0	4,0	4,0	100,0
Coût total d'entretien de la Technologie					24,25

Commentaires:

The costs are indicated per unit; a unit is one biochar kiln used on 1 a. The costs were calculated in 2014 for the vegetable beds, where the farmer uses around 2.5 kg/m2. He also uses Biochar on the rice seedling bed, with concentrations of around 0.5 kg/m2, 5 times less than in the vegetable patch. In the vegetable patch the farmer plants cucumber, pumpkin, onion, watermelon and leaf vegetables in the early wet season, before planting rice.

4.8 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

The factors affecting the cost the most are the biochar kiln, and the amount of added Biochar.

5.1 Climat

5.2 Topographie

5.3 Sols

5.4 Disponibilité et qualité de l'eau

5.5 Biodiversité

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 common / average land users
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 users have a title that is not recognized by the state.

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

Sols

Biodiversité: végétale, animale

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	pas connu
tempête de vent locale	pas connu

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)?

Commentaires:

The costs for the pyrolysis kiln were not borne by the land user. But as the farmer of this case study wants to build an own kiln as soon as the NGO needs it again, it is positive.

6.5 Adoption de la Technologie

Commentaires:

100% of land user families have adopted the Technology with external material support
100 land user families have adopted the Technology with external material support
Considering only the farmers applying the technology with this stove. Other farmers buy Biochar, or burn the rice husks and extinguish them. But those farmers are nearly impossible to quantify as it changes quickly. The support was the kiln, which is only a small part of the costs.
Considering only the farmers applying the technology with this stove. Other farmers buy Biochar, or burn the rice husks and extinguish them. But those farmers are nearly impossible to quantify as it changes quickly.
In another area of Cambodia where the Ministry of Agriculture, Forestry and Fisheries (MAFF) is doing Biochar research, there was such a strong adoption of Biochar use that there are no more control areas. In Kampong Chhnang, the use of Biochar starts to spread now.

6.7 Points forts/ avantages/ possibilités de la Technologie

Points forts/ avantages/ possibilités du point de vue de l'exploitant des terres
Less insect damages where Biochar is applied.
Good growth of vegetables, with increased yields especially for onions.
The rice seedlings are stronger, and the roots break less while transplanting, and the plants recover quickly.
The plants survive a short dry spell better.

Points forts/ avantages/ possibilités du point de vue du compilateur ou d'une autre personne ressource clé
Soil amendment with long-term effect, as Biochar has a long half-life period.
Buffering and raising of the pH, especially in sandy soils.
Less washing out of nutrients.

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?
Substrate to make Biochar (rice husks) is difficult to find in the area in big amounts, as only small rice mills are working there.	Rice husks are wasted in other places. Networking with other villages. Use other (waste) sources of organic matter like leaves.
Increased workload for the Biochar production (compensated by the increased yields).	Use a bigger kiln to decrease the workload.

Faiblesses/ inconvénients/ risques du point de vue du compilateur ou d'une autre personne ressource clé	Comment peuvent-ils être surmontés?
The energy produced during the pyrolysis is wasted.	Use it to power engines or as heating source. This would only be viable on large-scale kilns.

7.1 Méthodes/ sources d'information

7.2 Références des publications disponibles

Titre, auteur, année, ISBN:

Ithaka Journal

Disponible à partir d'où? Coût?

www.ithaka-institut.org

Titre, auteur, année, ISBN:

Biochar foundation

Disponible à partir d'où? Coût?

www.britishbiocharfoundation.org