Preparation of zai planting pits in a field. (PASP, GIZ)

Zai or tassa planting pits (Niger)

Zaï - Tassa (French)

Description

Zai planting pits are designed to collect rainwater and to conserve nutrients in order to improve crop production and food security.

Zai or tassa planting pits are an old farming technique rediscovered after the great drought of 1973/74 and later perfected by development partners working with the farmers. It involves digging planting pits with a diameter of at least 30 to 40 cm and 10 to 15 cm deep. They are spaced 70 to 80 cm apart, resulting in around 10,000 pits per hectare. Staggered rows of holes are dug perpendicularly to the slope. The earth dug out of the hole is piled up to form a small ridge around the rim, which captures water. A couple of handfuls of organic fertiliser or compost are put into each pit. They are normally made in the dry season before the first rains start. However, it is recommended that the pits be made immediately after the rainy season, when the soil is still moist and the weather is not too hot. If the pits are in place early in the dry season, they act as traps during the windy period in February and March, retaining rich dust carried by the harmattan and wind-blown organic matter. At least 3 tonnes of compost per hectare is recommended.

Purpose of the Technology: The arrangement of the pits in staggered rows ensures the most efficient collection of rainwater and slows the flow of water over the surface. The zai technique concentrates and conserves nutrients and water near the roots of the plants grown in them. The application of organic fertiliser directly around the plants is an economical use of a factor of production to which most farmers have limited access. It also reactivates biological activity, increases fertility and loosens the soil.
As zai planting pits restore degraded, uncultivated land, they lessen the pressure to clear other land for farming. They also reduce the vulnerability of plants during dry spells and droughts, ensuring crop production and improving food security.
Plots with zai planting pits (with fertiliser) average yields of 409 kg of millet grain per hectare, compared to 195 kg per hectare registered on control plots. Millet yields can therefore be doubled with this technique.

Establishment / maintenance activities and inputs: The zai technique requires high labour input. It is estimated that between 40 and 60 man-days per hectare are required, depending on the density of the pits. There is a mechanised system for making the holes, using a special animal-drawn plough, which considerably reduces the number of man-days required to 7 per hectare.
If the pits are prepared each year or once every two years (using the same pits or making new ones in the spaces between the old ones), soil fertility is restored and the crop cycle can be resumed. The application of organic fertiliser in sufficient quantities enables the plot to be cultivated sustainably. After five years, it can be farmed in the normal way.
Covering extensive areas with zai planting pits requires a high level of community mobilisation and effective organisation and logistics. Apart from this, the technique is very simple to implement and easily mastered by the farmers.

Natural / human environment: Zai planting pits are used on marginal or degraded land that is no longer cultivated, such as low-gradient pediments and land with encrusted soil in areas with rainfall levels of less than 800 mm a year. They are not recommended for sandy soils, as they are not stable when dug in this type of soil, or for valley bottoms, where they risk being flooded. Zai planting pits are particularly useful in areas where land use pressure is high, as they permit the rehabilitation of unproductive land for farming.
From the point of view of climate change adaptation, zai planting pits are particularly useful in areas with erratic or low rainfall, as they prevent the loss of water. As the fertiliser is placed inside the pits, it is not washed away by heavy rain.

Location

Location: Regions of Tillabéri, Filingué, Ouallam, Téra and Tahuoa, Niger, Niger

No. of Technology sites analysed:

Geo-reference of selected sites
  • 2.2165, 14.25192

Spread of the Technology:

In a permanently protected area?:

Date of implementation: 10-50 years ago

Type of introduction
Zai pits planted with millet. (PATECORE, GIZ)

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
Land use mixed within the same land unit: Yes - Agro-silvopastoralism

  • Cropland
    • Annual cropping: oilseed crops - groundnuts, cereals - millet, cereals - sorghum, legumes and pulses - peas
    • Tree and shrub cropping: mango, mangosteen, guava
    Number of growing seasons per year: 1
  • Grazing land
    • Nomadism
    • Semi-nomadic pastoralism
    • Cut-and-carry/ zero grazing
    • Improved pastures
  • Forest/ woodlands
    • (Semi-)natural forests/ woodlands. Management: Selective felling, Clear felling
    Products and services: Timber, Fuelwood, Fruits and nuts, Other forest products, Grazing/ browsing

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

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
  • soil erosion by wind - Et: loss of topsoil
  • chemical soil deterioration - Cn: fertility decline and reduced organic matter content (not caused by erosion)
  • biological degradation - Bc: reduction of vegetation cover
  • water degradation - Ha: aridification
SLM group
  • minimal soil disturbance
  • integrated soil fertility management
SLM measures
  • agronomic measures - A2: Organic matter/ soil fertility
  • structural measures - S4: Level ditches, pits

Technical drawing

Technical specifications
It involves digging planting pits with a diameter of at least 30 to 40 cm and 10 to 15 cm deep. They are spaced 70 to 80 cm apart, resulting in around 10,000 pits per hectare. Staggered rows of holes are dug perpendicularly to the slope. The earth dug out of the hole is piled up to form a small ridge around the rim, which captures water. A couple of handfuls of organic fertiliser or compost are put into each pit.

Location: Niger

Technical knowledge required for field staff / advisors: moderate
Technical knowledge required for land users: low

Main technical functions: control of dispersed runoff: retain / trap, control of dispersed runoff: impede / retard, control of concentrated runoff: retain / trap, control of concentrated runoff: impede / retard, increase in organic matter, increase in nutrient availability (supply, recycling,…), increase of infiltration, increase / maintain water stored in soil, water harvesting / increase water supply, sediment retention / trapping, sediment harvesting
Secondary technical functions: improvement of ground cover, stabilisation of soil (eg by tree roots against land slides), reduction in wind speed

Retention/infiltration ditch/pit, sediment/sand trap
Spacing between structures (m): 0.7-0.8
Depth of ditches/pits/dams (m): 0.15
Length of ditches/pits/dams (m): 0.3-0.4
Author: PASP

Establishment and maintenance: activities, inputs and costs

Calculation of inputs and costs
  • Costs are calculated:
  • Currency used for cost calculation: CFA Franc
  • Exchange rate (to USD): 1 USD = n.a CFA Franc
  • Average wage cost of hired labour per day: n.a
Most important factors affecting the costs
Labour: 40 to 60 man-days per hectare • marking out the rows perpendicular to the slope • digging pits in staggered rows • forming a ridge on the downhill side • applying organic fertiliser every two years (1 to 2 handfuls per pit, amounting to around 3 tonnes per hectare). Other costs: transportation of 30 cartloads of manure.
Establishment activities
  1. marking out the rows perpendicular to the slope (Timing/ frequency: None)
  2. digging pits in staggered rows (Timing/ frequency: None)
  3. forming a ridge on the downhill side (Timing/ frequency: None)
  4. A couple of handfuls of organic fertiliser or compost are put into each pit (Timing/ frequency: None)
Establishment inputs and costs
Specify input Unit Quantity Costs per Unit (CFA Franc) Total costs per input (CFA Franc) % of costs borne by land users
Labour
labour 1.0 16.3 16.3
transport and planting trees 1.0 12.3 12.3
Equipment
machine use 1.0 23.6 23.6
Plant material
seedlings
Total costs for establishment of the Technology 52.2
Total costs for establishment of the Technology in USD 52.2
Maintenance activities
  1. the pits are prepared each year or once every two years (using the same pits or making new ones in the spaces between the old ones (Timing/ frequency: None)
  2. applying organic fertiliser every two years (1 to 2 hand-fuls per pit, amounting to around 3 tonnes per hectare). (Timing/ frequency: None)

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: subtropics
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
Water quality refers to:
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
health

poor
good
education

poor
good
technical assistance

poor
good
employment (e.g. off-farm)

poor
good
markets

poor
good
energy

poor
good
roads and transport

poor
good
drinking water and sanitation

poor
good
financial services

poor
good

Impacts

Socio-economic impacts
Crop production
decreased
increased

risk of production failure
increased
decreased

production area (new land under cultivation/ use)
decreased
increased

farm income
decreased
increased

workload
increased
decreased

Socio-cultural impacts
food security/ self-sufficiency
reduced
improved

SLM/ land degradation knowledge
reduced
improved

Improved livelihoods and human well-being
decreased
increased


Plots with zai planting pits (with fertiliser) average yields of 409 kg of millet grain per hectare, compared to 195 kg per hectare registered on control plots. Millet yields can therefore be doubled with this technique. They also reduce the vulnerability of plants during dry spells and droughts, ensuring crop production and improving food security.

Ecological impacts
surface runoff
increased
decreased

soil moisture
decreased
increased

soil cover
reduced
improved

nutrient cycling/ recharge
decreased
increased

soil organic matter/ below ground C
decreased
increased

plant diversity
decreased
increased

wind velocity
increased
decreased

Waterlogging in planting pits after heavy rains
decreased
increased

Off-site impacts
downstream flooding (undesired)
increased
reduced

downstream siltation
increased
decreased

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

Gradual climate change
annual temperature increase

not well at all
very well
Climate-related extremes (disasters)
local rainstorm

not well at all
very well
local windstorm

not well at all
very well
drought

not well at all
very well
general (river) flood

not well at all
very well
Other climate-related consequences
reduced growing period

not well at all
very well
Answer: not known

Adoption and adaptation

Percentage of land users in the area who have adopted the Technology
  • single cases/ experimental
  • 1-10%
  • 11-50%
  • > 50%
Of all those who have adopted the Technology, how many have done so without receiving material incentives?
  • 0-10%
  • 11-50%
  • 51-90%
  • 91-100%
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
  • The arrangement of the pits in staggered rows ensures the most efficient collection of rainwater and slows the flow of water over the surface. The zai technique concentrates and conserves nutrients and water near the roots of the plants grown in them.
  • Zai planting pits are particularly useful in areas where land use pressure is high, as they permit the rehabilitation of unproductive land for farming. Therefore they lessen the pressure to clear other land for farming.
  • They also reduce the vulnerability of plants during dry spells and droughts, ensuring crop production and im- proving food security.
  • It permits a rational use of fertiliser. When fertiliser is spread on the surface of a plot without zai planting pits, it can be washed away by runoff.
  • very simple to implement and easily mastered by the farmers
Weaknesses/ disadvantages/ risks: land user's viewhow to overcome
Weaknesses/ disadvantages/ risks: compiler’s or other key resource person’s viewhow to overcome
  • The zai technique requires high labour input.
  • Zai planting pits are not recommended for light soils, as they fill in too quickly

References

Compiler
  • Dieter Nill
Editors
Reviewer
  • Alexandra Gavilano
  • Deborah Niggli
  • Nina Lauterburg
  • Fabian Ottiger
Date of documentation: Sept. 25, 2014
Last update: June 6, 2019
Resource persons
Full description in the WOCAT database
Linked SLM data
Documentation was faciliated by
Institution Project
Links to relevant information which is available online
  • Good Practices in Soil and Water Conservation. A contribution to adaptation and farmers´ resilience towards climate change in the Sahel. Published by GIZ in 2012.: http://agriwaterpedia.info/wiki/Main_Page
This work is licensed under Creative Commons Attribution-NonCommercial-ShareaAlike 4.0 International