Local Agricultural Research and Extension Centre LAREC
Society for Community Development in Cambodia SOFDEC
Society for Community Development in Cambodia SOFDEC
有助于对技术进行记录/评估的机构名称（如相关）CDE Centre for Development and Environment (CDE Centre for Development and Environment) - 瑞士
Manure, leaves and rice straw are gathered in a compost house and the produced compost is applied twice a year to the rice field.
Compost is produced in compost houses and is seen as a good and easy soil amendment. It is produced by mixing organic components (in this case study cow manure, rice straw, different leaves and ash) which are locally available. The ideal mix of ingredients shows an N-to-C ratio of approximately 1 to 25. By adding compost to the topsoil, its humus content is increased, and therefore the soil fertility and water holding capacity are enhanced. Although the technology can be applied with little technological knowledge, the land user’s workload is augmented. This can be detrimental in a human environment with constantly decreasing available labour force.
The purposes of compost production are multifaceted. From the land user’s point of view, the increased yields are certainly one of the most determining factors. This is due to the augmentation of organic matter and nutrients in the topsoil which results in a higher soil fertility. Therefore, the use of chemical fertilizer can be diminished while the yields stay the same. This results in the amelioration of the land user’s livelihood, since he needs to buy less fertilizer. Also, the improved soil structure (according to the land user, the soil is softer and easier to cultivate) and water retention capacity are of importance in this area, since the soils are sandy/loamy, and due to climate change the rainfall is more erratic and droughts more recurrent. Compost also buffers the soil’s pH and prevents acidification. As a consequence, the nutrient availability is increased. Finally, compost adds more biota to the soil.
First, the compost house is built. This can be done either with external inputs such as bricks, cement, and a tin roof (the initial investment is higher, but the recurrent maintenance activities lower), or with locally available, natural inputs such as rice straw and clay for the walls and dried sugar palm leaves for the roof (the initial investment is lower, however there are more recurrent maintenance activities which can be detrimental for the continuation of compost production).
Once the compost house is built, the organic matter (approximately 70 % cow manure, and 30 % rice straw and different leaves, with a small amount of ash) is collected in the surroundings and carried to the compost house. In this case study, compost is produced once during the dry season and once during the wet season. During the dry season, water is added to the organic matter in order to facilitate the composting process. Ideally, the organic matter should be turned in order to guarantee a complete composting process. However, this includes a rather big workload. As a result, turning is not always practiced in the area (high migration rates result in a decrease of available labour force).
When the composting process is completed, the compost is carried to the fields with the use of animal traction. This is done several times: once when the fields are plowed, once when the rice seedlings are transplanted and once while the rice is growing (“top dressing”).
The analyzed area is flat (slope < 2%), with a tropical climate with a (dry and a wet season), and the soils are mostly sandy or loamy. The soils have a low fertility, contain little organic matter, the pH is sinking, 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, land users notice more erratic rainfalls, temperatures rise and more recurrent droughts. 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.
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. This has detrimental effects on the agricultural activities. Furthermore, the civil war in the 1970s (Khmer Rouge) led to the loss of agricultural knowledge.
- 10-100 平方千米
A local NGO provided a training on compost making, about 5 years ago.
年作 - 具体指明作物:
- 谷类 - 水稻（湿地）
Longest growing period in days: 210, Longest growing period from month to month: June - December
- 牛 - 非奶牛牛肉
- 牛 - 非乳制品工作
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): Rice field: lack of nutrients, need fertilizer and compost otherwise no good yield. Not enough compost available, need to use also small amount of chemical fertilizer even though compost is applied. Lack of water. Soil erosion.
Main causes of degradation: soil management (Ploughing, soil is left bare for several weeks), crop management (annual, perennial, tree/shrub) (Rice monoculture (rice serves as staple food)), 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, influences 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, Heavy / extreme rainfall (intensity/amounts), land tenure (Some incidents of land grabbing, land use rights not clear), poverty / wealth
Manure, straw, ash and leaves are gathered in a compost hut, and later on dispersed on the paddy fields.
Technical knowledge required for field staff / advisors: moderate
Technical knowledge required for land users: low (It is not difficult to make compost, however it increases the workload of the land user. This might lead to the adaptation of the Technologies in order to decrease the additional workload.)
Main technical functions: increase in organic matter, increase in nutrient availability (supply, recycling,…)
Secondary technical functions: increase / maintain water stored in soil
Manure / compost / residues
Material/ species: Cow manure, mango leaves, rice straw, wood ash, green plants.
Quantity/ density: 3.7 t/ha
Remarks: 1 part at the beginning of the rainy season (rice transplantation), 1 part during the growing period
|1.||Construction of compost house|
|2.||Clay: Dig pit (10 cm) and add clay from the rice field|
|3.||Bricks and cement: make brick walls|
|施工材料||bricks and cement||1.0||31.0||31.0||100.0|
|施工材料||poles and nails||5.0||1.0||5.0||100.0|
|1.||Gather material for compost, prepares compost and adds water in dry season||all year round|
|2.||Bring compost to fields||June - September|
Machinery/ tools: Please note that the interviewed land user owns cows that are used for bringing the compost to the field. Hence, the costs for animal traction in this case study are zero.
1 compost house, around 4m^3.
Cost are affected by the availability of material to build the compost house (bricks, roof, etc.), which can be used long term.
Locally available, free material (sugar palm leaves for the roof, straw and clay for the walls) can be used as well, but it decays more quickly than the material used in this case-study (more recurrent maintenance activities).
The transport of manure to the fields is also an important expense. It is often done with the ox carts. As nearly all families owning oxen have a cart for different uses (firewood and product transportation), it is difficult to calculate this cost
- < 250毫米
- > 4,000毫米
Thermal climate class: tropics. 27°C to 35°C
- 0-100 m a.s.l.
- 101-500 m a.s.l.
- 501-1,000 m a.s.l.
- 1,001-1,500 m a.s.l.
- 1,501-2,000 m a.s.l.
- 2,001-2,500 m a.s.l.
- 2,501-3,000 m a.s.l.
- 3,001-4,000 m a.s.l.
- > 4,000 m a.s.l.
- 非常深（> 120厘米）
Difference in the involvement of women and men: The application of compost depends mainly on the commitment of the land users – gender and level of wealth are not determinative. However, the work is divided between men and women (physical strength).
Population density: 10-50 persons/km2
Annual population growth: 0.5% - 1%
Off-farm income specification: The land user manufactures handicrafts that she sells. Also, one of her daughters works in the garment industry. In addition, she owns pigs and chicken she sells.
- < 0.5 公顷
- 0.5-1 公顷
- 1-2 公顷
- > 10,000公顷
The farmer uses less chemical fertilizer. The yields remain the same on the short term.
Less chemical fertilizer used
contribution to human well-being
Due to the use of compost, land users are less dependent on chemical fertilizers. Therefore, the cost of production decreases while the income remains the same.
15% of land user families have adopted the Technology with external material support 20 land user families have adopted the Technology with external material support
Comments on acceptance with external material support: The technology was first introduced by a training (20 people attended), and then the neighbors of these farmers copied it. For each farmer trained, approximately 5 neighbors copied the technology.
85% of land user families have adopted the Technology without any external material support
130 land user families have adopted the Technology without any external material support
There is no trend towards spontaneous adoption of the Technology. Compost making increases the workload of the land users an that impedes the spontaneous adoption of the Technology.
|Less chemical fertilizer is used for the same yield, so the farmer can save money since she buys less chemical fertilizer.|
|Soil fertility is better. She sees more earthworms in the fields.|
|Ploughing became easier, because the soil is less hard after compost application.|
|Low cost, locally available and effective fertilizer/soil improving material.|
|Soil quality (organic matter, nutrient content, water retention, soil biota) is improved|
|The resilience is increased; farmers are less dependent on external inputs (fertilizer…)|
|Long term increased yields.|
|The collection of the material and the preparation of the compost (turning) is time consuming.||Monitoring the cost/benefit ratio to show the benefit to the farmer|
|It is difficult to transport the compost to the field.||Collaboration between neighbors to lower costs of hiring someone or lending machines.|
|She cannot make enough compost for all the fields||Work toward an integrated production.|
|Not enough organic matter to make enough compost (number of cattle is low, rice monoculture).||Work toward an integrated production.|
|Increased workload while labour availability is decreasing due to migration.||Increase the handicraft work on the farms. Diversification of the production with less labour intensive species.|
|Low motivation of the land user because the composting work has to be done each year again.||Monitoring to show the long-term cost/benefit ratio.|
|The composting process is not completely understood; weed and rice seeds survive and are growing on the fields.||Explanations about seed survival and dormancy to explain the purpose of composting.|
Society for Community Development in Cambodia SOFDEC