Polypit nursery [Nepal]
- Creation:
- Update:
- Compiler: Madhav Dhakal
- Editor: –
- Reviewers: David Streiff, Alexandra Gavilano
Plastic-Khalte nursery - Nepali
technologies_1498 - Nepal
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Expand all Collapse all1. General information
1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology
SLM specialist:
SLM specialist:
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:
Yes
2. Description of the SLM Technology
2.1 Short description of the Technology
Definition of the Technology:
A simple, inexpensive and practical method for raising healthy plant seedlings
2.2 Detailed description of the Technology
Description:
During the winter in Nepal’s middle mountains, the soil temperature generally remains at 5-10 degree celsius above the ambient air temperature. This principle was used to design a simple, inexpensive, and effective nursery technology for raising vegetable and horticulture seedlings in colder regions. The polypit technology allows seedlings to be raised by protecting them from the freezing temperatures that occur mostly at night.
Polypits are about 1m deep pits dug into the ground and covered with semitransparent polythene sheets, preferably UV stabilised and supported on bamboo frames. A 30 cm high mud wall is built across the slope on the upper side of the pit. The polythene sheet is sealed on the upper side of the pit, leaving three sides unsealed but held down with stones that can be lifted to access the pit. The base and sides of the polypit are left as they are with no form of plastering.
The polythene sheet covering the pit reduces the photosynthetic photon flux (PPF) by around 30% inside the pit, still allowing sufficient sunlight to reach the plants inside. The polythene is usually removed during the day from 11 am to 4 pm to allow full sunlight to reach the plants except on rainy and very cold days. A modified version of these polypits - only 70 cm deep - were used in the Jhikhu Khola watershed to grow vegetable seedlings during the winter. The pits can be made of any reasonable size depending on the number of seedlings to be grown and the layout of the land. The Jhikhu Khola pits were about 3m long, 1.5m wide, and 0.7m deep.
Since the polypits are closed at night, the CO2 released by the plants and soil microbes accumulates and increases to well above levels outside the pit. In a completely sealed polypit, the CO2 concentration could reach up to 3000 ppm during the night which would be harmful for plants. Thus the polythene cover is only loosely sealed along the edges at night to regulate and maintain the concentration of CO2 at about two to four times the ambient concentration.
The warmer protected conditions and CO2 enrichment leads to extra growth and biomass gain for plants grown inside the pits during the winter. This technology is easy to maintain with the only maintenance costs being to repair damaged polythene sheets and frames.
The polypit technology is useful for mountain farmers where water scarcity and low temperatures limit the potential to raise quality seedlings. The technology is being promoted in the northwest Indian state of Uttarakhand, although only a few farmers have adopted it so far. It is a very promising technology and its use should be encouraged by hill farmers and research and development organisations engaged in raising seedlings. The technology needs more participatory action research to improve it and to encourage more farmers to adopt it spontaneously.
2.3 Photos of the Technology
2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment
Country:
Nepal
Further specification of location:
Kavrepalanchowk district/Jhikhu Khola watershed
Specify the spread of the Technology:
- applied at specific points/ concentrated on a small area
Comments:
The technology was tested in the farmers field at Lamdihi and Spice Crop Development Centre. atTamaghat.
Map
×2.6 Date of implementation
If precise year is not known, indicate approximate date:
- less than 10 years ago (recently)
2.7 Introduction of the Technology
Specify how the Technology was introduced:
- during experiments/ research
Comments (type of project, etc.):
The technology is developed by G.B Pant Institute of Himalayan Environment and Development (GBPIHED) in Almora (India) for raising healthy plant saplings, named as polypit (Palni et al. 1994).
3. Classification of the SLM Technology
3.1 Main purpose(s) of the Technology
- improve production
3.2 Current land use type(s) where the Technology is applied
Cropland
- Annual cropping
Annual cropping - Specify crops:
- cereals - maize
- legumes and pulses - other
- oilseed crops - sunflower, rapeseed, other
- vegetables - other
- rice, wheat
Number of growing seasons per year:
- 3
Specify:
Longest growing period in days: 150; Longest growing period from month to month: Jun - Oct; Second longest growing period in days: 120; Second longest growing period from month to month: Nov - Feb
Comments:
Major land use problems (compiler’s opinion): Production is limited due to insufficient water during winter and the pre-monsoon season (from Nov-May); insufficient
farm income due to small landholdings; increased inputs of chemical fertilisers
Major land use problems (land users’ perception): Irrigation shortage during pre-monsoon and monsoon months.
Type of cropping system and major crops comments: Maize -vegetables/wheat-vegetables
3.4 Water supply
Water supply for the land on which the Technology is applied:
- mixed rainfed-irrigated
3.5 SLM group to which the Technology belongs
- full year planting
3.6 SLM measures comprising the Technology
structural measures
- S4: Level ditches, pits
4. Technical specifications, implementation activities, inputs, and costs
4.1 Technical drawing of the Technology
Technical specifications (related to technical drawing):
Poly pit covered with semi transparent plastic sheet which is supported on a bamboo farme.
Technical knowledge required for field staff / advisors: low
Technical knowledge required for land users: low
Main technical functions: protecting seedlings from frost, reduction of water loss, carbon dioxide enrichment
Structural measure: pit
Depth of ditches/pits/dams (m): 0.7m
Width of ditches/pits/dams (m): 1.5 m
Length of ditches/pits/dams (m): 3 m
Construction material (earth): a mud wall is made about 30 cm high from the ground, sloping on the two sides.
Construction material (wood): to place semi transparent plastic on a frame.
Construction material (other): plastic sheet: to cover the pit, rope, wire: frame preparation
Author:
Madhav Dhakal, A.K. Thaku
4.2 General information regarding the calculation of inputs and costs
Specify how costs and inputs were calculated:
- per Technology unit
Specify unit:
Polypit nursery
Specify currency used for cost calculations:
- USD
Indicate average wage cost of hired labour per day:
2.10
4.3 Establishment activities
Activity | Timing (season) | |
---|---|---|
1. | Determine the appropriate size (length, width and depth) of the pit | beginning of the winter season |
2. | Mark the area for soil excavation | beginning of the winter season |
3. | Excavate soil from the marked area | beginning of the winter season |
4. | Make a mud wall (~30 cm high) from the ground, sloping on two sides | beginning of the winter season |
5. | Make a bamboo fram of an appropriate size | beginning of the winter season |
6. | Lay the frame over the pit with one end resting on the mud wall | beginning of the winter season |
7. | Lay the plastic sheet over the frame | beginning of the winter season |
8. | Seal the polythene sheet on the higher side of the mud wall and leave three sides unsealed | beginning of the winter season |
9. | Lay the other three sides of the polythene sheet normally at ground level and weigh down with stones that can be removed to access the pit | beginning of the winter season |
10. | The base and sidesof the polypit do not need any form of plastering (even with mud) | beginning of the winter season |
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 | Construction of polypit nursery | Persons/unit | 1.0 | 2.1 | 2.1 | 100.0 |
Construction material | Plastic | unit | 1.0 | 4.0 | 4.0 | |
Construction material | Bamboo | unit | 1.0 | 1.3 | 1.3 | 100.0 |
Construction material | Rope | unit | 1.0 | 0.2 | 0.2 | 100.0 |
Total costs for establishment of the Technology | 7.6 | |||||
Total costs for establishment of the Technology in USD | 7.6 |
Comments:
Duration of establishment phase: 4 month(s)
4.5 Maintenance/ recurrent activities
Activity | Timing/ frequency | |
---|---|---|
1. | The polythene cover is opened to acclimatized the plants to the outside environment | 11:00- 16:00/Every day |
2. | Cleaning the pit | After trasplanting the seedlings/ once or twice in |
3. | Replacing the frame and polythene sheet if it gets damaged. | before raising nursery/In case of damage |
4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)
Specify input | Unit | Quantity | Costs per Unit | Total costs per input | % of costs borne by land users | |
---|---|---|---|---|---|---|
Labour | Maintaining the pit | Persons/unit | 1.0 | 2.1 | 2.1 | 100.0 |
Total costs for maintenance of the Technology | 2.1 | |||||
Total costs for maintenance of the Technology in USD | 2.1 |
Comments:
Machinery/ tools: wooden/iron peg, spade, shovel ,knife, and saw
The cost was calculated only for unit technology , and it can not be extrapolated on hectare basis as in 2006.
4.7 Most important factors affecting the costs
Describe the most determinate factors affecting the costs:
The plastic sheet , but it is easily affordable by the land users.
5. Natural and human environment
5.1 Climate
Annual rainfall
- < 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:
1200.00
Agro-climatic zone
- humid
Thermal climate class: subtropics
5.2 Topography
Slopes on average:
- flat (0-2%)
- gentle (3-5%)
- moderate (6-10%)
- rolling (11-15%)
- hilly (16-30%)
- steep (31-60%)
- very steep (>60%)
Landforms:
- plateau/plains
- ridges
- mountain slopes
- hill slopes
- footslopes
- valley floors
Altitudinal zone:
- 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.
Comments and further specifications on topography:
Altitudinal zone: 850 m a.s.l.
5.3 Soils
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)
- fine/ heavy (clay)
Topsoil organic matter:
- medium (1-3%)
If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.
Soil depth on average: Variable
Soil texture: Fine/ heavy (clay) is red soil with high clay content but medium (loamy, silty) is non red soil
Soil fertility is medium
Soil drainage / infiltration is medium
Soil water storage capacity is medium
5.4 Water availability and quality
Availability of surface water:
poor/ none
Water quality (untreated):
poor drinking water (treatment required)
Comments and further specifications on water quality and quantity:
Water quality (untreated): Also good, but more in rainy season (June- September), less in April/May; source: natural spring.
5.6 Characteristics of land users applying the Technology
Market orientation of production system:
- mixed (subsistence/ commercial)
Off-farm income:
- 10-50% of all income
Relative level of wealth:
- average
Individuals or groups:
- individual/ household
Level of mechanization:
- manual work
- animal traction
Gender:
- men
Indicate other relevant characteristics of the land users:
Land users applying the Technology are mainly common / average land users
Population density: 200-500 persons/km2
Annual population growth: 2% - 3%
100% of the land users are average wealthy and own 40% of the land.
Off-farm income specification: In most farm households off-farm income plays at least a minor and
increasingly a major role. Occasional opportunities for off-farm income present themselves in the form of daily
labour wages. Some households’ members receive regular salaries whilst an increasing number of Nepalis are
working in India, the Middle East, Malaysia and elsewhere and sending remittance incomes home.
Market orientation of production system: About 50 percent of the product , especially vegetables are grown commercially.
Level of mechanization: Manual labour for planting, irrigation, harvesting; Animals are used for field preparation and in valley bottom machines can be used for field preparation
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)?
- medium-scale
5.8 Land ownership, land use rights, and water use rights
Land ownership:
- individual, titled
Land use rights:
- individual
Water use rights:
- communal (organized)
6. Impacts and concluding statements
6.1 On-site impacts the Technology has shown
Socio-economic impacts
Production
land management
Comments/ specify:
the pit interrupted land preparation
Income and costs
farm income
Socio-cultural impacts
SLM/ land degradation knowledge
Comments/ specify:
About the polypit and their advantages
Ecological impacts
Soil
soil moisture
Comments/ specify:
Inside the polypit high relative humidity is maintained.
Other ecological impacts
Protection of seedlings against frost
Quality of seedlings
Comments/ specify:
customers prefer to buy seedlings grown in polypits compared to those grown outside
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? | |
---|---|---|---|
annual temperature | increase | well |
Climate-related extremes (disasters)
Meteorological disasters
How does the Technology cope with it? | |
---|---|
local rainstorm | well |
local windstorm | well |
Climatological disasters
How does the Technology cope with it? | |
---|---|
drought | well |
Hydrological disasters
How does the Technology cope with it? | |
---|---|
general (river) flood | well |
Other climate-related consequences
Other climate-related consequences
How does the Technology cope with it? | |
---|---|
reduced growing period | not known |
6.4 Cost-benefit analysis
How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:
positive
Long-term returns:
very positive
How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:
very positive
Long-term returns:
very positive
Comments:
The investment costs can be recouped within one season leading to positive results due to higher production.
6.5 Adoption of the Technology
- single cases/ experimental
If available, quantify (no. of households and/ or area covered):
2 households
Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
- 0-10%
Comments:
100% of land user families have adopted the Technology with external material support
2 land user families have adopted the Technology with external material support
Comments on acceptance with external material support: survey results
There is no trend towards spontaneous adoption of the Technology
Comments on adoption trend: There were not enough dissemination and awareness raising activities to inform farmers of the benefits of the technology and convince them to use it.
6.7 Strengths/ advantages/ opportunities of the Technology
Strengths/ advantages/ opportunities in the land user’s view |
---|
The survival rate for vegetable seedlings is higher and seedlings mature about two weeks earlier than if grown outside where they take about one month to be ready, leading to additional income for farmers How can they be sustained / enhanced? Every aspect of the technology should be highlighted through experience sharing programmes |
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view |
---|
Polypits are a simple, inexpensive, practical and effective technique for raising and protecting plant seedlings from severe winter temperatures.They can be called ‘poor farmers greenhouses’ How can they be sustained / enhanced? More dissemination and awareness raising activities are needed to inform more farmers about the benefits of this technology |
The high relative humidity in polypits means that watering only needs to be carried out once or twice a month in comparison to fi ve to six times for open nursery beds, thus saving labour and water How can they be sustained / enhanced? Every aspect of the technology should be highlighted through experience sharing programmes |
The more physical conditions and CO2 enrichment in the pits during the winter months are refl ected in the extra growth and biomass gain of plants grown inside the pits How can they be sustained / enhanced? As above |
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? |
---|---|
In the demonstration, the bamboo frame to hold the sheet was too heavy making it diffi cult for the farmer to remove the frame and work inside. | Use a modifi ed frame with a space built in to allow a person to enter the pit easily without having to remove the frame. |
Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view | How can they be overcome? |
---|---|
In completely sealed polypits, the CO2 concentration can become so high during the night that it harms the plants | Only loosely seal the sheet at night to regulate and maintain the CO2 concentration |
7. References and links
7.1 Methods/ sources of information
7.2 References to available publications
Title, author, year, ISBN:
Bhuchar, S. (2004) Polypit: a Green-chamber for Poor Farmers, an article prepared for PARDYP Quarterly e-Newsletter-8, ICIMOD, Kathmandu
Available from where? Costs?
ICIMOD
Title, author, year, ISBN:
Palni, L.M.S.; Bhuchar, S.; Kothyari, B.P. (1994) ‘A Simple Polypit can Greatly Reduce Nursery Time of Tree Seedlings”. In Journal of HIMA-PARYAVARAN, 6(2):10-11
Available from where? Costs?
GBPIHED- Almora
Title, author, year, ISBN:
Vyas, P.; Bisht, M.S.; Bhuchar, S.; Sharma, S.; Palni, L.M.S. (1999) ‘Polypit: An Improved Technique for Raising Nursery Plants’. In Journal of Sustainable Forestry, 8(1): 43-59
Available from where? Costs?
GBPIHED- Almora
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