Traditional irrigated rice terraces [Nepal]

Tari khet (Nepali)

technologies_1099 - Nepal

Completeness: 65%

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)

SLM specialist:
SLM specialist:
Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)
Book project: where the land is greener - Case Studies and Analysis of Soil and Water Conservation Initiatives Worldwide (where the land is greener)
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
District Soil Conservation Office (DSCO) - Nepal
Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)
ICIMOD International Centre for Integrated Mountain Development (ICIMOD) - Nepal

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:


2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

Level bench terraces with risers protected by fodder grasses, used for the irrigated production of rice, potatoes and wheat

2.2 Detailed description of the Technology


The level bench terrace is a traditional technology that makes irrigated crop production possible on steep, erosion prone slopes. The majority of such terraces in Nepal were constructed by hand many generations ago, but some new land - mostly already under rainfed cultivation on forward sloping terraces - is still being converted into irrigated terraces. The initial costs for the construction of the terraces are extremely high – and annual maintenance costs are considerable also. The climate is humid subtropical, slopes are steep (30%-60%) and soils generally have a sandy loam texture. Terraces are cropped by farmers who mostly have less than 0.5 ha of land each.
Two to three annual crops are grown per year starting with paddy rice during the monsoon, followed by potatoes and/or wheat.
While terrace beds are usually 2–6 m in width, to save labour they are made as wide as they can be without increasing the danger of slips/land slides. Surveying was traditionally done by eye, but now a water-tube level may be used. Risers are 0.8-1.5 m high with a small lip (20-25 cm). The slope of the riser varies from 80 to 160%, depending on the initial gradient of the hill. Stones are incorporated in the risers if available, and grass species such as bermuda grass (Cynodon dactylon) and napier (Pennisetum purpureum) may be planted for stabilisation and as cattle fodder. The risers are compacted (with hoes) to improve ponding conditions for the paddy rice. Twice per year the risers are scraped with a special tool: (1) at the time of land preparation for paddy rice the lower part of riser is sliced, but the upper part is left protected with grasses against the monsoon rains; (2) at the time of wheat planting the whole riser (including the lip) is scraped and spread as green manure on the terrace.
Terraces are flooded with water for paddy rice cultivation: a smaller amount of water is diverted into the fields for other crops. Excess water is drained to the lower terrace by openings in the lip, which are filled with rice straw in order to filter out sediments. The depth of water for rice - when flooded completely - is normally between 10 and 15 cm. Fertility is maintained by addition of farmyard manure, spreading the scraped soil from the riser, and also through sediment carried in the irrigation water. Nowadays, mineral fertilizers are also applied.

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:


Further specification of location:

Manmata subwatershed

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:
  • 0.1-1 km2

Total area covered by the SLM Technology is 1 km2.

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



  • Annual cropping
Annual cropping - Specify crops:
  • cereals - rice (wetland)
  • root/tuber crops - potatoes
  • wheat
Number of growing seasons per year:
  • 2

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


Major cash crop: Potatoes
Major food crop: Rice and wheat

Major land use problems (compiler’s opinion): - steep slopes, not suitable for agriculture in their original state (better for forestry, agroforestry, horticulture, and fruit
- small and scattered plots of land
- land users find chemical fertilizers and water expensive
- there is water scarcity from September to May and too much rain in the monsoon period (June to August) with the danger of erosion and collapse of the terraces

3.4 Water supply

Water supply for the land on which the Technology is applied:
  • rainfed

3.5 SLM group to which the Technology belongs

  • cross-slope measure

3.6 SLM measures comprising the Technology

agronomic measures

agronomic measures

  • A2: Organic matter/ soil fertility
vegetative measures

vegetative measures

  • V2: Grasses and perennial herbaceous plants
structural measures

structural measures

  • S1: Terraces

Main measures: agronomic measures, vegetative measures, structural measures

Type of agronomic measures: manure / compost / residues, mineral (inorganic) fertilizers

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

soil erosion by water

  • Wt: loss of topsoil/ surface erosion
  • Wg: gully erosion/ gullying
  • Wm: mass movements/ landslides

Main type of degradation addressed: Wt: loss of topsoil / surface erosion, Wg: gully erosion / gullying, Wm: mass movements / landslides

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:
  • prevent land degradation

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Layout of irrigated terraces. Openings in the lips drain excess water, grass cover stabilises lips and risers (right). After harvesting of rice, the grass is scraped off the lower part of the risers (left) and spread on the terrace beds

Technical knowledge required for field staff / advisors: high

Technical knowledge required for land users: high

Main technical functions: reduction of slope angle, reduction of slope length, increase / maintain water stored in soil, control of dispersed and concentrated runoff, increase in soil fertility

Secondary technical functions: improvement of ground cover, water harvesting / increase water supply, water spreading

Manure / compost / residues
Material/ species: green/farmyard manure

Vegetative measure: fodder grass at risers

Material: earth


Mats Gurtner

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:


Specify currency used for cost calculations:
  • USD

4.3 Establishment activities

Activity Timing (season)
1. Planting grasses including bermuda grass (Cynodon dactylon). during monsoon
2. Construct bunds (risers) with soil from upper and lower sides before monsoon
3. Level terrace beds (soil moved from upper to lower part of terraces). before monsoon
4. Make lips on edges of terraces before monsoon
5. Compact risers before monsoon
6. Construct irrigation canal before monsoon
7. Make openings in lips for drainage of excess water before monsoon
8. Test-irrigate terrace for accurate levelling during monsoon
9. Plant grasses including Bermuda grass (Cynodon dactylon) during monsoon
10. After 2–3 years: some narrow terraces may be merged to form single, wider terraces during monsoon

4.5 Maintenance/ recurrent activities

Activity Timing/ frequency
1. Flood the paddy fields .. (June/July) / Repeated 3–4 times during
2. Slice/scrape grass and soil on lower part of risers and spread on terraces (when flooded, June/July) /
3. Plant rice and apply mineral fertilizer (June/July). /
4. Harvest rice (October) /
5. Apply manure (cattle manure), after rice harvest (October). /
6. Slice/scrape grass and soil from whole of risers and spread on terraces; repairsmall collapses/slumps in risers (October/November) /
7. Pprepare land (November) /
8. Apply mineral fertilizer (November/December). /
9. Irrigate Nov. / repeated several times during cultivation
10. Harvest of potato/wheat (January-March). /
11. Planting of rice June,July /
12. planting of potatoes, wheat November /
13. Repair of small collapses/slumps in risers. (Oct./Nov.)/

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 Labour ha 1.0 350.0 350.0 100.0
Equipment Tools ha 1.0 5.0 5.0 100.0
Fertilizers and biocides Fertilizer ha 1.0 185.0 185.0 100.0
Fertilizers and biocides Compost/manure ha 1.0 300.0 300.0 100.0
Total costs for maintenance of the Technology 840.0
Total costs for maintenance of the Technology in USD 840.0

Machinery/ tools: hoe, spade, baskets, (doko), special tool for scraping

Current establishment costs are very difficult to determine since the majority of the traditional terraces were
established a long time ago. Costs depend closely on the present state of the land (forward sloping terraces or uncultivated) and the need for irrigation canals. Farmers say that construction now could cost up to US$ 10,000 per ha if carried out by hand at full labour cost. The cost given for maintening the terraces (approx. US$ 840 per ha) includes all associated annual crop production costs. In this case study, 100% of the construction costs were borne by 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
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%)
  • 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.

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):
  • coarse/ light (sandy)
  • medium (loamy, silty)
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 fertility is medium

Soil drainage / infiltration is good because of the geology and soil texture (loam)

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
Individuals or groups:
  • individual/ household
Level of mechanization:
  • manual work
  • animal traction
Indicate other relevant characteristics of the land users:

Off-farm income specification: hired labour (on other farmers’ fields) or as porters

Market orientation of production system: Subsistence (rice/wheat) and commercial (potatoes)

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

5.8 Land ownership, land use rights, and water use rights

Land ownership:
  • individual, not titled
Land use rights:
  • leased
  • individual

Land use rights: leased (90% of farmers), individual (10%)

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts


crop production


fodder production


fodder quality


production area


land management

Comments/ specify:

the technology is a part of a complex farming system

Income and costs

expenses on agricultural inputs


farm income


economic disparities

Comments/ specify:

not everyone has access to land for irrigation


Other socio-economic impacts

Livestock fodder


Socio-cultural impacts

community institutions


SLM/ land degradation knowledge


conflict mitigation

Comments/ specify:

when the agreed and scheduled water extraction amounts are exceeded

Ecological impacts

Water cycle/ runoff

excess water drainage


soil moisture


soil cover


soil loss

Climate and disaster risk reduction

landslides/ debris flows

Comments/ specify:

poor maintenance of topmost terraces may cause landslides

Other ecological impacts

Soil fertility




Number of crabs in irrigation water make holes in the terrace risers

Comments/ specify:

which in turn can cause pipe erosion and riser collapse

6.2 Off-site impacts the Technology has shown

reliable and stable stream flows in dry season


downstream flooding


downstream siltation


groundwater/ river pollution


Groundwater recharge


Soil moisture and nutrients downstream


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 not well
local windstorm not well
Climatological disasters
How does the Technology cope with it?
drought not well
Hydrological disasters
How does the Technology cope with it?
general (river) flood not well

Other climate-related consequences

Other climate-related consequences
How does the Technology cope with it?
reduced growing period not well

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:

very negative

Long-term returns:


How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:


Long-term returns:

very positive

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?
  • 91-100%

100% of land user families have adopted the Technology without any external material support

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Income and production increased

How can they be sustained / enhanced? Proper management of the terraces
(including all maintenance activities)
Easier to cultivate flat terraces/less labour required (after establishment of terraces)
Work sharing: traditional terraces are part of a long tradition of work sharing within the community with no external labourneeded

How can they be sustained / enhanced? Prevent loss of well established traditions and norms
Technology is easy to understand/apply.

Increased opportunities for irrigation facilities: farmers without level terraces are not allowed (by the irrigation committee at village level) or do not claim irrigation water
The irrigation element of this technology fosters social bonds within the community

How can they be sustained / enhanced? Prevent loss of well established norms and

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
Decreased grass production (grazing area reduced) Promote planting of high value grass species on risers (such as bermuda grass).
The farmers believe that the terraces are too narrow (for efficient use of tractors); they would like to have wider terraces Investigate possibilities of constructing wider paddy rice terraces on steep slopes,
which, according to present experience, is not possible.
High labour costs for establishment.

7. References and links

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

There is considerable literature on the construction and maintenance of irrigated terraces in general, but no references thatspecifically describe the traditional paddy rice terraces in Nepal

Links and modules

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