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Pitting - Machakos experience (Kenya)

Wamatengo pits, Kitui Pitting, Katumani pitting

Description

A system of interlocking crescent shaped trenches approximately 5-12 square metres, 0.5 m deep and 0.3 m high formed down slope using the xecavated spoil

The pitting is started at the top of the eroded slope or below a cutoff drain which interced all runoff from the above land. The pits are roughly circular in shape and are dug to form interlocking micro catchment, each about 2m squared in area. A semi circular bank 15 - 30cm high is constructed to the lower side of the pit using soil removed from the trench. At the centre of each trench, a hole is excavated to a depth of at least 50cm to act as the main reservoir for runoff water from the catchment above. The pit are used for soil conservation and rehabilitation of the grazingland. Runoff is captured in small quantities, thus preventing the build up of large erosive flows. Cowpeas, grass could be sown on the ridges at onset of the rains. Construction is by hoes and once the vegetation has established, maintenance is minimal. Forage should be cut and fed to animals. The technology is suitable in areas with 6-8% slope in areas with 500-800mm rainfall. There is need to maintain the cutoff drain after a rainy season

Location

Location: Eastern Province, Kenya

No. of Technology sites analysed:

Geo-reference of selected sites
  • 37.6108, -1.0427

Spread of the Technology: evenly spread over an area (approx. < 0.1 km2 (10 ha))

Date of implementation: less than 10 years ago (recently)

Type of introduction
-

Classification of the Technology

Main purpose
  • improve production
  • reduce, prevent, restore land degradation
  • conserve ecosystem
  • protect a watershed/ downstream areas – in combination with other Technologies
  • preserve/ improve biodiversity
  • reduce risk of disasters
  • adapt to climate change/ extremes and its impacts
  • mitigate climate change and its impacts
  • create beneficial economic impact
  • create beneficial social impact
Land use

  • Grazing land -

Water supply
  • rainfed
  • mixed rainfed-irrigated
  • full irrigation

Number of growing seasons per year: 2
Land use before implementation of the Technology: n.a.
Livestock density: n.a.

Purpose related to land degradation
  • prevent land degradation
  • reduce land degradation
  • restore/ rehabilitate severely degraded land
  • adapt to land degradation
  • not applicable
Degradation addressed
  • 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)
  • water degradation - Ha: aridification
SLM group
  • water diversion and drainage
SLM measures
  • structural measures - S2: Bunds, banks, S4: Level ditches, pits

Technical drawing

Technical specifications
Technical knowledge required for field staff / advisors: moderate

Technical knowledge required for land users: moderate

Main technical functions: control of dispersed runoff: retain / trap, improvement of ground cover, water harvesting / increase water supply

Secondary technical functions: control of raindrop splash, increase in organic matter, increase of infiltration

Construction material (earth): this is the spoil obtained from the excavation

Vegetation is used for stabilisation of structures.

Change of land use type: during establishment of grass/legume

Establishment and maintenance: activities, inputs and costs

Calculation of inputs and costs
  • Costs are calculated:
  • Currency used for cost calculation: Kenya Shilling
  • Exchange rate (to USD): 1 USD = 78.0 Kenya Shilling
  • Average wage cost of hired labour per day: 2.56
Most important factors affecting the costs
when cutoff drain is to be constructed, particularly in the dry spell when the ground is hard. When the construction is done when the ground is too hard the cost of labour is high.
Establishment activities
  1. reseeding grass (Timing/ frequency: rainy days)
  2. pit excavation (Timing/ frequency: before rains)
  3. bund formation (Timing/ frequency: before rains)
  4. legume planting (Timing/ frequency: before rains)
  5. fencing (Timing/ frequency: before rains)
Maintenance activities
  1. repair pits (Timing/ frequency: after rains/twice)
  2. desilt of cutoff drains (Timing/ frequency: before rains/each cropping season)
  3. sealing gaps on the fence (Timing/ frequency: during the rain / twice)

Natural environment

Average 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
  • sub-humid
  • semi-arid
  • arid
Specifications on climate
Thermal climate class: tropics
Slope
  • 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
Altitude
  • 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.
Technology is applied in
  • convex situations
  • concave situations
  • not relevant
Soil depth
  • 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)
  • fine/ heavy (clay)
Soil texture (> 20 cm below surface)
  • coarse/ light (sandy)
  • medium (loamy, silty)
  • fine/ heavy (clay)
Topsoil organic matter content
  • high (>3%)
  • medium (1-3%)
  • low (<1%)
Groundwater table
  • on surface
  • < 5 m
  • 5-50 m
  • > 50 m
Availability of surface water
  • excess
  • good
  • medium
  • poor/ none
Water quality (untreated)
  • good drinking water
  • poor drinking water (treatment required)
  • for agricultural use only (irrigation)
  • unusable
Is salinity a problem?
  • Yes
  • No

Occurrence of flooding
  • Yes
  • No
Species diversity
  • high
  • medium
  • low
Habitat diversity
  • high
  • medium
  • low

Characteristics of land users applying the Technology

Market orientation
  • subsistence (self-supply)
  • mixed (subsistence/ commercial
  • commercial/ market
Off-farm income
  • less than 10% of all income
  • 10-50% of all income
  • > 50% of all income
Relative level of wealth
  • very poor
  • poor
  • average
  • rich
  • very rich
Level of mechanization
  • manual work
  • animal traction
  • mechanized/ motorized
Sedentary or nomadic
  • Sedentary
  • Semi-nomadic
  • Nomadic
Individuals or groups
  • individual/ household
  • groups/ community
  • cooperative
  • employee (company, government)
Gender
  • women
  • men
Age
  • children
  • youth
  • middle-aged
  • elderly
Area used per household
  • < 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
Scale
  • small-scale
  • medium-scale
  • large-scale
Land ownership
  • state
  • company
  • communal/ village
  • group
  • individual, not titled
  • individual, titled
Land use rights
  • open access (unorganized)
  • communal (organized)
  • leased
  • individual
Water use rights
  • open access (unorganized)
  • communal (organized)
  • leased
  • individual
Access to services and infrastructure

Impacts

Socio-economic impacts
Socio-cultural impacts
Ecological impacts
soil loss
increased
decreased

Quantity before SLM: 20.5
Quantity after SLM: 7

Off-site impacts

Cost-benefit analysis

Benefits compared with establishment costs
Short-term returns
very negative
very positive

Long-term returns
very negative
very positive

Benefits compared with maintenance costs
Short-term returns
very negative
very positive

Long-term returns
very negative
very positive

Climate change

-

Adoption and adaptation

Percentage of land users in the area who have adopted the Technology
  • single cases/ experimental
  • 1-10%
  • 10-50%
  • more than 50%
Of all those who have adopted the Technology, how many have done so without receiving material incentives?
  • 0-10%
  • 10-50%
  • 50-90%
  • 90-100%
Number of households and/ or area covered
NA
Has the Technology been modified recently to adapt to changing conditions?
  • Yes
  • No
To which changing conditions?
  • climatic change/ extremes
  • changing markets
  • labour availability (e.g. due to migration)

Conclusions and lessons learnt

Strengths: land user's view
Strengths: compiler’s or other key resource person’s view
Weaknesses/ disadvantages/ risks: land user's viewhow to overcome
Weaknesses/ disadvantages/ risks: compiler’s or other key resource person’s viewhow to overcome

References

Compiler
  • Paul Mutuku Kimeu
Editors
Reviewer
  • David Streiff
Date of documentation: June 5, 2011
Last update: March 22, 2017
Resource persons
Full description in the WOCAT database
Linked SLM data
Documentation was faciliated by
Institution Project
Key references
  • some aspects of soil conservation on grazing lands in Thomas , D B et al. SWC in Kenya. 1989.:
This work is licensed under Creative Commons Attribution-NonCommercial-ShareaAlike 4.0 International