Technologies

Rehabilitation of ancient terraces [Peru]

Andenes / Anchacas / Patapatas

technologies_1506 - Peru

Completeness: 69%

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:

Marquina Rodolfo

Centro de Estudios y Promoción del Desarrollo – DESCO

Peru

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)
Centro de Estudios y Promoción del Desarrollo (DESCO) - Peru

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

1.5 Reference to Questionnaire(s) on SLM Approaches (documented using WOCAT)

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

Repair of ancient stone wall bench terraces, and of an associated irrigation and drainage system.

2.2 Detailed description of the Technology

Description:

The level bench terrace system in the Colca valley of Peru dates back to 600 years AD. Since then the terraces have been continuously used for crop production, but due to lack of maintenance they have deteriorated, and the population has lost its traditional knowledge of repair.
The rehabilitation of the terraces recreates their original structural design. Broken sections are cleared and the various materials - stones, topsoil, subsoil and weeds - are removed and separated. The foundation is re-established, followed by construction of the stone wall (the ‘riser’). Backfilling with subsoil then takes place; this is consolidated and finally covered with topsoil. Simultaneously the complementary irrigation and drainage systems are reconstructed.
The rehabilitated terraces efficiently conserve soil and water on steep slopes, and they create a favourable microclimate for crops, reducing loss of stored heat at night by minimising air movement (preventing frosts) and mitigating dry conditions through moisture conservation. The main economic benefits are from increased yields and crop diversification.
Terraces are spaced and sized according to slope, eg on a 50% slope, terraces are 4 m wide with a 2 m high riser between terrace beds. Stones of ancient terraces had been widely used to build walls for boundary marking after privatisation of land, therefore a large amount of stone had to be provided by splitting rocks and transporting from other locations.
The area is characterised by steep slopes with loamy-sandy, moderately deep soils (on the terrace beds). Most of the annual precipitation (ca. 350 mm) falls within a period of 3 months, which makes irrigation necessary. The farmers in the area own, on average, 1.2 hectares of arable land, divided into around six plots in different agro-ecological zones. Production is mainly for subsistence. Important supportive technologies include agronomic measures such as improved fallow, early tillage, ridging, and intercropping. Tree and shrub planting at the base of terrace walls is an optional measure with the aim of stabilising the walls, diversifying production and again ensuring a good microclimate. On average 250 trees/ha are planted; these are mainly native species such as c’olle (Buddleia spp.), mutuy (Cassia sp.), molle (Schinus molle: the ‘pepper tree’) and various fruit trees including capulí (Prunus salicifolia).

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:

Peru

Region/ State/ Province:

Río Colca,Caylloma, Arequipa

Comments:

Total area covered by the SLM Technology is 100 km2.

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • through projects/ external interventions

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

3.2 Current land use type(s) where the Technology is applied

Cropland

Cropland

  • Annual cropping
Annual cropping - Specify crops:
  • cereals - maize
  • fodder crops - alfalfa
  • legumes and pulses - beans
  • root/tuber crops - potatoes
Specify:

Longest growing period in days: 120 Longest growing period from month to month: Dec - Apr

Grazing land

Grazing land

Intensive grazing/ fodder production:
  • Cut-and-carry/ zero grazing
Comments:

Main crops (cash and food crops): Major food crop: Potatoes, maize,beans, etc
Main animal species and products: Alfalfa (cut and carry)

Major land use problems (compiler’s opinion): - Loss of productive capacity: 30% of the agricultural land lost due to degraded terraces, severe deforestation (through
cutting for fuelwood), overgrazing and burning of grazing areas.
- Inefficient irrigation practices (flooding) due to poor maintenance of irrigation system (and drainage system in poor
condition), flood irrigation leads to deterioration of terraces.
- Loss of traditional knowledge of ancestral crop management practices (abandonment of appropriate rotation practices, lack of residue incorporation/recycling, unsystematic crop layout).

3.4 Water supply

Comments:

Water supply: mixed rainfed - irrigated and rainfed

3.5 SLM group to which the Technology belongs

  • cross-slope measure
  • irrigation management (incl. water supply, drainage)
  • water diversion and drainage

3.6 SLM measures comprising the Technology

structural measures

structural measures

  • S1: Terraces
Comments:

Main measures: structural measures

Secondary measures: agronomic measures, vegetative measures

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
chemical soil deterioration

chemical soil deterioration

  • Cn: fertility decline and reduced organic matter content (not caused by erosion)
water degradation

water degradation

  • Ha: aridification
Comments:

Main type of degradation addressed: Wt: loss of topsoil / surface erosion, Wg: gully erosion / gullying, Cn: fertility decline and reduced organic matter content, Ha: aridification

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:
  • restore/ rehabilitate severely degraded land

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

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

Rehabilitated ancient terraces with high stone risers. Two options for irrigation and drainage of excess water are shown: outlets in the risers (left) and a broad water channel cutting perpendicularly through the terraces (right).

Technical knowledge required for field staff / advisors: high

Technical knowledge required for land users: moderate

Main technical functions: control of dispersed runoff: retain / trap, reduction of slope angle, reduction of slope length, increase of infiltration, water harvesting / increase water supply, improvement of microclimate

Secondary technical functions: control of dispersed runoff: impede / retard, control of concentrated runoff: impede / retard, increase in organic matter, increase / maintain water stored in soil, sediment retention / trapping, sediment harvesting, improvement of soil structure

Author:

Mats Gurtner

4.3 Establishment activities

Activity Timing (season)
1. Separation of materials of collapsed wall: subsoil, topsoil, stone, weeds. dry period.
2. Cleaning and re-establishment of the foundation according to originalstructure. dry period.
3. Cutting stones from rocks (blasting and splitting); transporting. dry period.
4. Reconstruction of the stone wall, building on the basis of remainingintact structures of ancient terraces; simultaneous reconstructionof irrigation channels and complementary structures. dry period.
5. Backfilling with subsoil, moistening soil and consolidation with motor dry period.
6. Covering with fertile topsoil. dry period.
7. Levelling of terrace bed and completion of riser edge (lip). dry period.
8. Planting of trees below terrace walls (optional). dry period.
9. Improved fallow, early tillage, ridging, and intercropping (supportivemeasures). dry period.

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 Labour ha 1.0 560.0 560.0 40.0
Labour Construction supervisor (days) ha 1.0 60.0 60.0
Equipment Machine use ha 1.0 180.0 180.0 40.0
Equipment Tools ha 1.0 300.0 300.0 40.0
Plant material Seedlings ha 1.0 100.0 100.0
Construction material Stone ha 1.0 200.0 200.0 40.0
Total costs for establishment of the Technology 1400.0
Total costs for establishment of the Technology in USD 1400.0

4.5 Maintenance/ recurrent activities

Activity Timing/ frequency
1. Irrigation system cleaning.
2. Clearing weeds from stone wall (dry season)./
3. Inspection of the stone walls’ stability (before sowing)./
4. Repair structures (rainy season)./
5. Tree and root pruning.

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 25.0 25.0 100.0
Equipment Tools ha 1.0 100.0 100.0 100.0
Total costs for maintenance of the Technology 125.0
Total costs for maintenance of the Technology in USD 125.0
Comments:

Machinery/ tools: A-frame,tape measure,motor drill,wheelbarrow,shovel,pick,steel bar,sledgehammer,hoe,hand compressor.

Person days needed for rehabilitation of 1 ha of ancient terrace system depend on degree of deterioration, the dimensions of the wall, slope angle (the steeper the more terraces) and availability of stones. In the case of the project, under a typical situation, for physical rehabilitation of 1 ha with 6 terraces, each ca 600 m long, 3–4 m wide and 2 m high, with one third of the main structures in disrepair, 18 men and 7 women work for 5 days; shrub planting is extra. Land users bear 35% of the overall costs: they also provide food for the group during work. The programme pays the rest. 450 m3 of additional stones are required to repair the broken parts, the cost includes blasting/splitting rocks and transport to the construction site.
Supportive agronomic measures and agricultural inputs (seeds and manure) are not included. Maintenance costs vary considerably, depending on the specific situation: an average is taken here.

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
  • semi-arid

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:

Landforms: Also hill slopes (ranked 2) and footslopes (ranked 3)
Slopes on average: Also hilly (ranked 2) and rolling (ranked 3)

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)
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.

Soil fertility: Medium (ranked 1, used for maize) and low (ranked 2)
Topsoil organic matter: Low (low recycling of organic matter)
Soil drainage/infiltration: Medium

5.6 Characteristics of land users applying the Technology

Off-farm income:
  • less than 10% of all income
Indicate other relevant characteristics of the land users:

Off-farm income specification: main source is wage labour in the valleys
Market orientation of grazing land production system: Subsistence (ranked 1) and mixed (ranked 2, 30% for market)
Market orientation of grazing land production system: Subsistence (ranked 1, complementary to crop production) and commercial/market (ranked 2, income generation to meet basic needs)

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
Comments:

Average area of land owned or leased by land users applying the Technology: Also 2-5 ha (ranked 3)

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

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

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

crop production

decreased
increased
Comments/ specify:

Average 30%

land management

hindered
simplified
Comments/ specify:

Careful management required (water and livestock)

Income and costs

farm income

decreased
increased

workload

increased
decreased
Comments/ specify:

Easier crop management (level bench, alignment of crops). On the other hand increased labour constraints: heavy work, const. Maintenance. Heavy work by establishment

Other socio-economic impacts

Efficiency

decreased
increased
Comments/ specify:

Efficient use of irrigation water and fertilizers

Input constraints

increased
decreased
Comments/ specify:

Tools

Ccarcity of stones (in some places)

increased
decreased

Ecological impacts

Water cycle/ runoff

excess water drainage

reduced
improved
Soil

soil moisture

decreased
increased

soil cover

reduced
improved

soil loss

increased
decreased

nutrient cycling/ recharge

decreased
increased
Biodiversity: vegetation, animals

plant diversity

decreased
increased

animal diversity

decreased
increased

habitat diversity

decreased
increased
Other ecological impacts

Regular crop growth and development

decreased
increased

Improved microclimate

decreased
increased
Comments/ specify:

Reduced wind; conserving heat

6.2 Off-site impacts the Technology has shown

reliable and stable stream flows in dry season

reduced
increased

downstream flooding

increased
reduced

downstream siltation

increased
decreased

6.4 Cost-benefit analysis

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

neutral/ balanced

Long-term returns:

very positive

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

positive

Long-term returns:

very positive

6.5 Adoption of the Technology

If available, quantify (no. of households and/ or area covered):

240

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 11-50%
Comments:

90% of land user families have adopted the Technology with external material support

2160 land user families have adopted the Technology with external material support

10% of land user families have adopted the Technology without any external material support

240 land user families have adopted the Technology without any external material support

There is a moderate trend towards spontaneous adoption of the Technology

Comments on adoption trend: There is a moderate trend towards spontaneous adoption.
40% of terraces have been rehabilitated in 7 districts (8 micro-watersheds) of the Colca valley.

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Facilitation of crop management activities (crop alignment, easier tillage with oxen plough, efficiency of pest control, etc)

How can they be sustained / enhanced? Appropriate crop management (see measures mentioned in description).
Improved microclimate facilitates crop growth and crop diversification

How can they be sustained / enhanced? Complete with improved agronomic practices and agroforestry.
Increased yields and food security

How can they be sustained / enhanced? Conserve crop diversity and genetic variety.
Cultural heritage

How can they be sustained / enhanced? Conservation of traditional practices
Facilitation of crop management activities (crop alignment, easier tillage with oxen plough, efficiency of pest control, etc)-->Appropriate crop management (see measures mentioned in description). - Improved microclimate facilitates crop growth and crop diversification-->Complete with improved agronomic practices and agroforestry. - Increased yields and food security-->Conserve crop diversity and genetic variety Cultural heritage-->Conservation of traditional practices.
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Traditional technology is of great value and adapted to local conditions

How can they be sustained / enhanced? Awareness raising of the local population on maintenance of terraces.
Successful implementation is product of evaluation, analysis and documentation
of experiences

How can they be sustained / enhanced? Further appraisal of the technology.
Soil maintained on steep slopes, no soil loss due to water erosion

How can they be sustained / enhanced? Continuous maintenance and appropriate management through training.
More efficient use of irrigation/rain water, longer storage of soil moisture

How can they be sustained / enhanced? Permanent maintenance of structure.
Maintenance of soil fertility

How can they be sustained / enhanced? Recycling of organic matter.

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?
Vulnerability of terraces to damage by grazing animals Do not allow grazing on short terraces with high stone walls.
Land users are not skilled in repair of broken sections in the terrace system More training on maintenance and conservation.
Vulnerability of terraces to damage by grazing animals-->Do not allow grazing on short terraces with high stone walls. - Land users are not skilled in repair of broken sections in the terrace system-->More training on maintenance and conservation. Editors’ comments: Terracing systems on hillsides date back to the beginning of agriculture. Often these feature walls (‘risers’) built of stone, and sometimes they are used for irrigation – as in this case from Peru. While many ancient systems have fallen into disrepair with out-migration of rural populations, this is an example of project-based rehabilitation.
Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
Specialised work, not easy to carry out – complex system of different
structures
Promote applied research and extension.
High rehabilitation costs; increased by loss of traditional forms of reciprocal
work, and a trend towards individualism
Reactivate and strengthen
traditional labour systems based on reciprocity and mutual help.
Limited availability of stones impedes the rehabilitation process Carry
stones from adjacent or remote places, give training in rock splitting.
Not appropriate for use of agricultural machines Awareness creation.
Private properties, but not titled Promote the legalisation of titles to
facilitate the access to credit and technical assistance.

7. References and links

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

Mejia Marcacuzco AP Folleto de divulgación: Andenes, construcción y mantenimiento. (undated).

Title, author, year, ISBN:

Treacy, JM (undated) LasChacras de Coporaque: Andenes y riego en el valle del Colca. Instituto de Estudios Peruanos. DESCO

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