Agroforestry with Acacia senegal - cultivated part (Julie Zähringer)

Agroforestry with Acacia senegal (Senegal)

Description

An agroforestry system, dominated by Acacia senegal, developed through protection of all naturally regenerating trees with improvement of soil properties through presence of trees, application of manure and a fallow rotation.

Acacia senegal is the dominating woody species in this agroforestry system. To improve soil properties and crop production, organic manure is applied and a fallow system practiced. One part of the field is being cultivated with either millet (Pennisetum typhoides), cowpea (Vigna unguiculata), groundnut (Arachis hypogaea) or maïz (Zea mais] whereas the other part is left fallow for two years before rotation.

Purpose of the Technology: Initially, the main objective of the land user applying the technology was to improve soil properties and crop production in his fields by maintaining any tree and protecting natural regeneration when preparing his land for cultivation. With the start of exploiting Acacia senegal for the exudates, gum arabic, the potential of revenue increase through gum exploitation became evident and the objective shifted from soil protection to gum exploitation.

Establishment / maintenance activities and inputs: Because of knowledge his father passed on to him, the land user applying this agroforestry practice believes that any tree in his fields is useful and should be protected.Through the technique of assisted natural regeneration, trees naturally growing in the field are protected to reach mature age instead of being cut to clear area for cultivation. The only inputs related to this technology are those for seeds for crop cultivation. During the 3-4 months of gum Arabic exploitation, the land user is obliged to survey his fields day and night, as intruders try to tap the Acacia senegal trees illegally. However, this task is fulfilled by the landuser himself and does not involve expenses for payed manpower.

Natural / human environment: This SLM technology site is located in the sylvopastoral region of the Ferlo in the north of Sénégal. The agro-climatic zone is classified as semi-arid with mean annual precipitation of 300-400 mm. The main land use type in the area is extensive pastoralism followed by rainfed agriculture. Pastoralism is primarily practiced by transhumant Fula (Peulh) herders and further by Mauritanian Moor herders with herds of dromedaries. Vegetation cover in the area has been largely degraded due to cutting for domestic uses and cattle feeding, bushfires and overgrazing. The soil is exposed to wind erosion which carries away nutrients in the topsoil and therefore declines soil fertility. During intense rains in the rainy season, surface runoff is accelerated and leads to the formation of gullies and ravines.

Location

Location: Barkédji, Louga, Senegal

No. of Technology sites analysed:

Geo-reference of selected sites
  • -14.9131, 15.271

Spread of the Technology:

In a permanently protected area?:

Date of implementation: 10-50 years ago

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
Land use mixed within the same land unit: Ja - Agroforestry

  • Cropland
    • Annual cropping: cereals - millet, legumes and pulses - peas, oilseed crops - groundnuts
    Number of growing seasons per year: 1
  • Forest/ woodlandsTree types: Acacia senegal

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, Bq: quantity/ biomass decline, Bs: quality and species composition/ diversity decline
SLM group
  • agroforestry
  • rotational systems (crop rotation, fallows, shifting cultivation)
SLM measures
  • agronomic measures - A1: Vegetation/ soil cover
  • vegetative measures - V1: Tree and shrub cover

Technical drawing

Technical specifications

Establishment and maintenance: activities, inputs and costs

Calculation of inputs and costs
  • Costs are calculated:
  • Currency used for cost calculation: n.a.
  • Exchange rate (to USD): 1 USD = n.a
  • Average wage cost of hired labour per day: n.a
Most important factors affecting the costs
seeds for crop planting
Establishment activities
  1. Get all the seeds (Timing/ frequency: None)
Establishment inputs and costs
Specify input Unit Quantity Costs per Unit (n.a.) Total costs per input (n.a.) % of costs borne by land users
Plant material
Seeds for millet ha 1.0 1.68 1.68
Seeds for groundnut ha 1.0 5.25 5.25
Seeds for cowpeas ha 1.0 7.85 7.85
Total costs for establishment of the Technology 14.78
Total costs for establishment of the Technology in USD 14.78
Maintenance activities
  1. Sowing of crops (Timing/ frequency: beginning of growing season once a year)
  2. Application of manure (Timing/ frequency: several times during growing season)

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
Average annual rainfall in mm: 300.0
During one rainy season (july-september), dry period from october-mai
Thermal climate class: tropics, in the sylvopastoral zone of the Ferlo
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?
  • Ja
  • Nee

Occurrence of flooding
  • Ja
  • Nee
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


As the land user can count on income from gum exploitation he is less vulnerable to crop failure

product diversity
decreased
increased

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


Applies especially for fallow part, cultivation might be entirely given up

farm income
decreased
increased


Income from gum arabic exploitation

diversity of income sources
decreased
increased

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

conflict mitigation
worsened
improved

Ecological impacts
soil cover
reduced
improved


Applies for the part left fallow, in the cultivated part negligible

soil loss
increased
decreased


Applies for the part left fallow, in the cultivated part negligible

nutrient cycling/ recharge
decreased
increased


Biological N-fixation (A.senegal), but amount questionable

soil organic matter/ below ground C
decreased
increased


Through plant litterfall, application of manure

biomass/ above ground C
decreased
increased


Mainly applies for the part left fallow, in the cultivated part only little

plant diversity
decreased
increased


Applies for the cultivated part only

pest/ disease control
decreased
increased


Birds building nests in trees on fields

wind velocity
increased
decreased


Applies for the part left fallow, in the cultivated part negligible

Off-site impacts
wind transported sediments
increased
reduced

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

the landuser is expecting a rise in income through increased gum production

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
Answer: not known
local windstorm

not well at all
very well
Answer: not known
drought

not well at all
very well
Answer: not known
general (river) flood

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

not well at all
very well

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%
Number of households and/ or area covered
1
Has the Technology been modified recently to adapt to changing conditions?
  • Ja
  • Nee
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
  • increase of crop production

    How can they be sustained / enhanced? maintain or increase number of trees in fields
  • increase of income

    How can they be sustained / enhanced? assist natural regeneration of Acacia senegal
  • provision of shade for cattle and increased availability of manure as consequence

    How can they be sustained / enhanced? maintain or increase number of trees in fields
Strengths: compiler’s or other key resource person’s view
  • increase of soil fertility
    increase of soil organic matter

    How can they be sustained / enhanced? increase the number of trees with positive impact on soil fertility
    improve manure application and increase number of trees in cultivated part
  • reduction of wind erosion

    How can they be sustained / enhanced? increase tree abundance
  • maintenance of woody species diversity
  • improvement of soil cover

    How can they be sustained / enhanced? increase tree abundance
  • little to no costs of establishment
Weaknesses/ disadvantages/ risks: land user's viewhow to overcome
  • surveillance of Acacia senegal trees during exploitation season required establish a fence
  • crop damaging birds find a habitat to build nests in trees put scarecrows
Weaknesses/ disadvantages/ risks: compiler’s or other key resource person’s viewhow to overcome
  • tendency towards a monoculture of Acacia senegal (in the part of the field left fallow) encourage natural regeneration of other local species as well

References

Compiler
  • Julie Zähringer
Editors
Reviewer
  • Fabian Ottiger
  • Alexandra Gavilano
Date of documentation: Des. 16, 2011
Last update: Junie 20, 2019
Resource persons
Full description in the WOCAT database
Linked SLM data
Documentation was faciliated by
Institution Project
This work is licensed under Creative Commons Attribution-NonCommercial-ShareaAlike 4.0 International