Intercropping of eggplants between mango trees using rice straw mulching to reduce evaporation [Cambodia]
- Compiler: Navin Chea
- Editors: Sok Pheak, Sophea Tim
- Reviewers: Alexandra Gavilano, Nicole Harari, SO Than, TOM SAY
Growing eggplant under mango trees
technologies_2255 - Cambodia
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1. General information
1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology
Key resource person(s)
Official of Chetr Borei district office of agriculture, forestry and fisheries:
Chetr Borei district office of agriculture, forestry and fisheries
Acting chief of Preaek Prasab District Office of Agriculture, Forestry and Fisheries:
Chief of District Office of Agriculture, Forestry and Fisheries, Sambo:
Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)Scaling-up SLM practices by smallholder farmers (IFAD)
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)Royal University of Agriculture (RUA) - Cambodia
1.3 Conditions regarding the use of data documented through WOCAT
The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:
1.4 Declaration on sustainability of the described Technology
Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?
2. Description of the SLM Technology
2.1 Short description of the Technology
Definition of the Technology:
Intercropping of eggplants between mango trees and the application of straw mulching on the plants’ roots and the land so as to retain soil moisture by reducing heat-induced evaporation. When the rice straw rots, it provides organic matter and makes soil less compact. The farmer can benefit from the short-term crop for a period of three years before the mango trees fully produce fruits.
2.2 Detailed description of the Technology
Intercropping of a short term crop between the fruit trees which are the long term crop (mango trees which will provide fruit in their third year depending on the species variety and maintenance) is a best agroforestry practice which provides both economic and environmental benefits. When the mango trees are still young and have not yet produced fruit, there is also free space between the trees. In order to gain additional benefits and to avoid weeds growing that could be harmful to the mango trees, the growing of eggplants with rice straw mulching could provide co-benefits in the form of maintaining, weed control, watering, and the application of fertilizer for the mango trees. The eggplants could produce fruit within three months after having been planted and they can be harvested for several months in a year. In this way farmers can generate income for their daily expenditure before the mango trees produce fruit. By using this technology, farmers are able to improve their livelihoods compared with before.
In this SLM technology, the mango trees, eggplants and mulched rice straw interact beneficially. In the dry season, the trees provide some shade for the eggplants and the rice straw on the eggplants' roots and land helps retain soil moisture reducing evaporation, and this prevents the crops from withering during hot days. In addition, when the farmer waters the eggplant,it also provides water to the trees. In rainy season, the rice straw and the eggplants act as an important vegetation cover for the prevention of soil erosion through surface run-off during heavy rainfall. Besides the rice straw and its decayed materials are a crucial food source for micro-organisms in the soil that improve the cycling of nutrients and the soil less compact, enabling a better growth of the crops.
In this technology, the mango trees are planted in row with an interval of six metres and the eggplants are transplanted among the rows of trees ensuring that there is a distance of one metre between each plant within a row, and a distance of 1.5 metres between one row and another. The pit for each mango tree is 70x70x70cm and a mixture of burned rice husk, cow manure and woody herb is added as fertilizer in the bottom of the pit. When planting, the compost or slurry from the of the bio-digester is also mixed in with the soil. Eggplant seedlings are transplanted in 10-cm holes using 20-30 day-old seedlings. Then the farmer applied rice straw mulching on the roots of eggplant and mango trees' roots and applied on the free space of the land. The transplanted eggplants are watered on a daily basis, while the watering of the mango trees is carried out twice per week.
Weeding is done regularly so that the weeds do not absorb too many nutrients from the soil even there is no much weed. The farmer applies compost twice a year, usually once at the beginning of the rainy season in May, and also in October.
When the eggplants start to produce fruit, it takes around one hour for the farmer to harvest the crop on a daily basis. Weeding is sometimes carried out during the harvest. It is suggested that one should consider a rotation of short-term crops in order to maximize the benefits of this SLM technology, because growing one type of crop could absorb exact the same nutrients from the soil so the second crop growing are not very good and could cause disease outbreak on the crop. The rotation of crops in this case could include eggplants, mung beans, sweet corn or cucumbers. However it should examining the market demands as well.
2.3 Photos of the Technology
2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment
Region/ State/ Province:
Kamboa village, Kou Loab commune, Chetr Borei district, Kratie
Further specification of location:
Specify the spread of the Technology:
- evenly spread over an area
If the Technology is evenly spread over an area, specify area covered (in km2):
If precise area is not known, indicate approximate area covered:
- < 0.1 km2 (10 ha)
This technology is practiced on a crop land behind the house.
Land area for applying the technology is 18m x 30 m = 540 square meter.
2.6 Date of implementation
Indicate year of implementation:
2.7 Introduction of the Technology
Specify how the Technology was introduced:
- through projects/ external interventions
Comments (type of project, etc.):
The farmer used to join a field visit to Battambang province supported by SNV in CHAIN project coordinated by Chetr Borei District Office of Agriculture, Forestry and Fisheries.
3. Classification of the SLM Technology
3.1 Main purpose(s) of the Technology
- improve production
- reduce, prevent, restore land degradation
- create beneficial economic impact
- Obtaining economic benefits from the short-term crops while the mango is not ready to produce fruits, and the rice straw helps reduce evaporation maintaining soil moisture.
3.2 Current land use type(s) where the Technology is applied
Land use mixed within the same land unit:
Specify mixed land use (crops/ grazing/ trees):
- Annual cropping
- Perennial (non-woody) cropping
- Tree and shrub cropping
Annual cropping - Specify crops:
- cereals - maize
- legumes and pulses - beans
Annual cropping system:
Vegetables - wheat/barley/oat/upland rice
Perennial (non-woody) cropping - Specify crops:
- flower crops - perennial
Tree and shrub cropping - Specify crops:
- mango, mangosteen, guava
Number of growing seasons per year:
Mango is a long-term crop, eggplant (4 months), sweet corn (2 months), mung bean (2 months)
Is intercropping practiced?
Mango is a long-term crop, eggplant (4 months), sweet corn (2 months), mung bean (2 months)
Livestock density: 19 cows and the manure is used in biodigester production and slurry from biodigester is used for cultivation crops. Those number of cows are enought for biodigester production everyday.
3.3 Has land use changed due to the implementation of the Technology?
Has land use changed due to the implementation of the Technology?
- Yes (Please fill out the questions below with regard to the land use before implementation of the Technology)
3.4 Water supply
Water supply for the land on which the Technology is applied:
- mixed rainfed-irrigated
Pond and wells, but the wells went dry in 2016.
3.5 SLM group to which the Technology belongs
- improved ground/ vegetation cover
- integrated soil fertility management
3.6 SLM measures comprising the Technology
- A1: Vegetation/ soil cover
- A2: Organic matter/ soil fertility
- A3: Soil surface treatment
- V1: Tree and shrub cover
- V2: Grasses and perennial herbaceous plants
3.7 Main types of land degradation addressed by the Technology
soil erosion by water
- Wt: loss of topsoil/ surface erosion
chemical soil deterioration
- Cn: fertility decline and reduced organic matter content (not caused by erosion)
physical soil deterioration
- Pc: compaction
- Pu: loss of bio-productive function due to other activities
- Bc: reduction of vegetation cover
- Bl: loss of soil life
- Bp: increase of pests/ diseases, loss of predators
- Ha: aridification
3.8 Prevention, reduction, or restoration of land degradation
Specify the goal of the Technology with regard to land degradation:
- reduce land degradation
- restore/ rehabilitate severely degraded land
In this area, the soil has low fertility. The use of compost from the biodigester and rotating the short-term crops helps improve soil quality.
4. Technical specifications, implementation activities, inputs, and costs
4.1 Technical drawing of the Technology
Technical specifications (related to technical drawing):
The technology contains the 25 total planted mango trees and 350 eggplants. The area of applying this technology is 540square meters( width 18 meters and length 30 meters).
Vanny Om and Sophea Tim
4.2 General information regarding the calculation of inputs and costs
Specify how costs and inputs were calculated:
- per Technology area
Indicate size and area unit:
540 square meter
other/ national currency (specify):
If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:
Indicate average wage cost of hired labour per day:
4.3 Establishment activities
|1.||Ploughing the soil to sun dry||May|
|2.||Digging the pits for mango trees||May|
|3.||Applying the mixture of cow manure, burned rice hush and woody herb in the pits||May|
|4.||Planting the mango trees||May|
|5.||Applying slurry from biodigester on the plant roots.||June|
|6.||Prepare the soil mixing with cow manure, apply lime to grow the crops.||June|
|7.||Digging holes and transplant eggplant||June|
|8.||Spreading the rice straw||June|
4.4 Costs and inputs needed for establishment
|Specify input||Unit||Quantity||Costs per Unit||Total costs per input||% of costs borne by land users|
|Labour||Ploughing the soil to sun dry||Peson-day||0.35||30000.0||10500.0||100.0|
|Labour||Digging the pits for mango trees||Peson-day||5.8||30000.0||174000.0||100.0|
|Labour||Applying fertilizers and lime||Peson-day||0.35||30000.0||10500.0||100.0|
|Plant material||Mango trees||Tree||25.0||8000.0||200000.0||100.0|
|Plant material||Eggplant seeds||Bag||1.0||8000.0||8000.0||100.0|
|Fertilizers and biocides||lime||kg||25.0||2000.0||50000.0||100.0|
|Fertilizers and biocides||Compost from biodigester||Tank||50.0||2000.0||100000.0||100.0|
|Construction material||Handle basket||Paire||1.0||7000.0||7000.0||100.0|
|Construction material||Soil digger||Piece||1.0||25000.0||25000.0||100.0|
|Total costs for establishment of the Technology||625000.0|
|Total costs for establishment of the Technology in USD||156.25|
The farmer pays for the expense to create the technology using his own saving, the compost is own produced from the biodigester, which was supported by a project.
4.5 Maintenance/ recurrent activities
|1.||Check the crops regularly to make sure the crops not fall down or demage by insects.||Once every 5 days|
|2.||Soil preparation after each short-term crop's harvest||After harvest|
|3.||Making small pit around the mango tree||When mango tree getting bigger|
|4.||Apply compost and fertilzer KCL(15-15-15)||May and October|
|5.||Watering the crops||Daily especially in dry season|
|6.||Purchase water pumping machine||After growing mango trees|
The pumping machine costs 1,600,000 Riel
4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)
If you are unable to break down the costs in the table above, give an estimation of the total costs of maintaining the Technology:
The pumping machine costs 1,600,000 Riel.
4.7 Most important factors affecting the costs
Describe the most determinate factors affecting the costs:
The cost of water pumping machine is high, cost of mango trees and eggplant seeds, cost of hiring labor to plough the soil. But she doesn't expend on buying fertilizer because she use her own cow manure.
5. Natural and human environment
- < 250 mm
- 251-500 mm
- 501-750 mm
- 751-1,000 mm
- 1,001-1,500 mm
- 1,501-2,000 mm
- 2,001-3,000 mm
- 3,001-4,000 mm
- > 4,000 mm
Specify average annual rainfall (if known), in mm:
Specifications/ comments on rainfall:
In 2015 the annual rainfall was 1138.2 mm, in 2014 1696.50, in 2013 1661.8 mm.
Indicate the name of the reference meteorological station considered:
Department of Meteorology, Ministry of Water Resources and Meteorology (2015)
There are two seasons: dry and rainy seasons
Slopes on average:
- flat (0-2%)
- gentle (3-5%)
- moderate (6-10%)
- rolling (11-15%)
- hilly (16-30%)
- steep (31-60%)
- very steep (>60%)
- mountain slopes
- hill slopes
- valley floors
- 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.
Indicate if the Technology is specifically applied in:
- not relevant
Soil depth on average:
- very shallow (0-20 cm)
- shallow (21-50 cm)
- moderately deep (51-80 cm)
- deep (81-120 cm)
- very deep (> 120 cm)
Soil texture (topsoil):
- medium (loamy, silty)
Soil texture (> 20 cm below surface):
- fine/ heavy (clay)
Topsoil organic matter:
- low (<1%)
If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.
In the past, this area was degraded forest. Soil quality is low and contains some stone. After using compost and applying the technology the soil quality has improved.
5.4 Water availability and quality
Ground water table:
Availability of surface water:
Water quality (untreated):
good drinking water
Is water salinity a problem?
Is flooding of the area occurring?
Comments and further specifications on water quality and quantity:
Groundwater in this area contains some minerals, so the farmer store it in a pond before irrigating the crops. Rainwater and tap water from other areas is the source of drinking water.
5.6 Characteristics of land users applying the Technology
Sedentary or nomadic:
Market orientation of production system:
- commercial/ market
- > 50% of all income
Relative level of wealth:
Individuals or groups:
- individual/ household
Level of mechanization:
- manual work
- mechanized/ motorized
Age of land users:
Indicate other relevant characteristics of the land users:
He is 45 years old.
5.7 Average area of land used by land users applying the Technology
- < 0.5 ha
- 0.5-1 ha
- 1-2 ha
- 2-5 ha
- 5-15 ha
- 15-50 ha
- 50-100 ha
- 100-500 ha
- 500-1,000 ha
- 1,000-10,000 ha
- > 10,000 ha
Is this considered small-, medium- or large-scale (referring to local context)?
5.8 Land ownership, land use rights, and water use rights
- individual, titled
Land use rights:
Water use rights:
5.9 Access to services and infrastructure
employment (e.g. off-farm):
roads and transport:
drinking water and sanitation:
6. Impacts and concluding statements
6.1 On-site impacts the Technology has shown
Production is increased because in previous land no crops cultivation, but now there are more than one crop.
The quality of crop is improved by using animal manure and compost.
risk of production failure
The risk of production failure is reduced due to having more than one crop. Before, the farmer had no crops so he had no crop production for selling on the market.
Before it is the infertile soil but after more crops is cultivated and using compost, the soil fertility is improved.
Water availability and quality
demand for irrigation water
Crop cultivation under mango tree is needed watering everyday.
Income and costs
expenses on agricultural inputs
The farmer has his own cows, so she could have cow manure as the natural fertilizer for the crops. In addition, she also has biodigester which could get the slurry to produce compost without buying fertilizer from supplier.
Generating regular income from selling eggplant.
diversity of income sources
There are short-term and long-term crops cultivation so it can generate annual and monthly income.
Regular maintenance of the crops is needed.
food security/ self-sufficiency
Household consumption and selling.
Compost from biodigester is good for both the producer and consumers.
Having some trees provides shade, it is less hot and fresh air.
Water cycle/ runoff
Due to rice straw mulching and shade of the mango trees.
Due to rice straw mulching.
Due to vegetation cover as eggplant and mango trees.
When the rice straw rots, it become organic fertilizer benefit to the soil. Moreover, cow manure and compost helps to improve the soil structure.
soil organic matter/ below ground C
The rotten of rice straw, the application of cow manure and compost could increase the soil organic matter.
Biodiversity: vegetation, animals
The beneficial species are increased through slurry from biodigester and application of animal manure. The land user notices to increase of earthworm, ant, termite, small frog etc.
pest/ disease control
Pests still occur but not many.
Climate and disaster risk reduction
Drought impacts is reduced due to rice straw mulching and shade from mango tree.
6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)
Gradual climate change
Gradual climate change
|Season||increase or decrease||How does the Technology cope with it?|
|seasonal temperature||dry season||increase||well|
|seasonal rainfall||wet/ rainy season||decrease||well|
|other gradual climate change||Variation in rainfall pattern||increase||moderately|
Climate-related extremes (disasters)
|How does the Technology cope with it?|
|How does the Technology cope with it?|
|How does the Technology cope with it?|
|insect/ worm infestation||moderately|
6.4 Cost-benefit analysis
How do the benefits compare with the establishment costs (from land users’ perspective)?
How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
While the mango has not produce fruits, harvest is done with the short-term crops.
6.5 Adoption of the Technology
Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
There are 6 households who want to adopt the practice to generate more income. Even if they cannot follow all activities they still select some activities from this technology to implement.
Has the Technology been modified recently to adapt to changing conditions?
If yes, indicate to which changing conditions it was adapted:
- climatic change/ extremes
Specify adaptation of the Technology (design, material/ species, etc.):
Rice straw mulching reduces evaporation.
6.7 Strengths/ advantages/ opportunities of the Technology
|Strengths/ advantages/ opportunities in the land user’s view|
|Possibility to grow other crops with the mango trees.|
|When watering the eggplants, it also benefits the mango trees.|
|Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view|
|The land is used effectively as it will take at least three years before the mango trees start to provide a harvest.|
|Rice straw helps to retain soil moisture, reduces evaporation and improves nutrient cycling.|
|Generation of a substantial income for the family.|
|The soil is not degraded by growing short term crops, crop rotation and using cow manure, composting and slurry from biodigester.|
6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them
|Weaknesses/ disadvantages/ risks in the land user’s view||How can they be overcome?|
|Some carterpillars could damage the eggplants.||Manually pick off the insects' eggs and do not apply pesticide which could cause health risks.|
|Insecure market demand; while eggplants are in peak production.||Try to access various markets and mobile sale of the product at other people's households.|
|Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view||How can they be overcome?|
|When the mango trees are quite mature could not grow eggplant between trees.||Select short-term crops that only need a smaller amount of light such as turmeric galanga.|
|Require compost and a biodigester||Promote animal husbandry including cows, pigs and poultry.|
7. References and links
7.1 Methods/ sources of information
- field visits, field surveys
One specific location
- interviews with land users
- interviews with SLM specialists/ experts
When were the data compiled (in the field)?
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