Green manures grown for production of seed to allow its distribution for use at larger scale. (Gerba Leta)

Green Manures (Ethiopia)

Xa'oo Magarisaa

Description

Green manures are fast-growing legumes sown in a field, weeks or even months before the main crop is planted. These are plants that are deliberately grown for incorporation into the soil to improve fertility and organic matter content.

Green manures are grown with the prime purpose of building up as much biomass as possible. However, they also play a role in covering the ground and protecting it from solar radiation and soil erosion. These are plants that are deliberately grown for incorporation into the soil to improve soil fertility and organic matter content. They are generally fast-growing legumes sown in a field several weeks or months before the main crop is planted. Legumes are chosen due to their ability to fix atmospheric nitrogen, their drought tolerance, quick growth, and adaptation to adverse conditions. Green manures have the potential to restore soil fertility and have an ameliorating effect on climate change via the sequestration of atmospheric carbon.
Green manures supply the soil with great amounts of fresh biomass. After incorporation into the soil, the biomass is decomposed by soil organisms within a few weeks under humid and warm conditions. Most nutrients are then readily available to a new crop. A small proportion is also transformed into stable soil organic matter, contributing to better soil structure, better aeration, improved drainage, increased soil water and nutrient holding capacity, and reduced erodibility of the soil by wind or water. Soil microbial activity is increased, as is the availability of macro and micronutrients in forms that the plants can use. They also have a root system that holds the soil in place.

Green manures are often applied to degraded land that demands management interventions. The purpose of introducing the technology reported here is primarily to multiply seeds for the scaling out of the technology. Among the common green manure crops which are being used in Ethiopia are lupin and lablab. Land users benefit from the sale of the seed itself as well as the fact that green manures increase production and help to changes unproductive and abandoned land into productive assets. This technology has been distributed to virtually all Integrated Soil Fertility Management project (ISFM+) intervention woredas/regions as a component of intervention technologies/practices.

Location

Location: Mirga Mute, Bedele district, Oromia, Ethiopia

No. of Technology sites analysed: 2-10 sites

Geo-reference of selected sites
  • 36.34407, 8.48284

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

In a permanently protected area?: Nee

Date of implementation: 2020

Type of introduction
A lupin crop grown as green manure right before its incorporation into the soil. (GERBA LETA)

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: Nee

  • Cropland
    • Annual cropping
    Number of growing seasons per year: 1
    Is intercropping practiced? Nee
    Is crop rotation practiced? Nee
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
  • chemical soil deterioration - Cn: fertility decline and reduced organic matter content (not caused by erosion), Ca: acidification
  • physical soil deterioration - Pc: compaction
  • biological degradation - Bc: reduction of vegetation cover, Bl: loss of soil life
SLM group
  • integrated crop-livestock management
  • improved ground/ vegetation cover
  • integrated soil fertility management
SLM measures
  • agronomic measures - A1: Vegetation/ soil cover, A2: Organic matter/ soil fertility, A3: Soil surface treatment
  • management measures - M5: Control/ change of species composition

Technical drawing

Technical specifications

Establishment and maintenance: activities, inputs and costs

Calculation of inputs and costs
  • Costs are calculated: per Technology area (size and area unit: 1.5 Sanga; conversion factor to one hectare: 1 ha = 1ha = 8 sanga)
  • Currency used for cost calculation: ETB
  • Exchange rate (to USD): 1 USD = 53.12 ETB
  • Average wage cost of hired labour per day: 200
Most important factors affecting the costs
Cost is highly volatile in Ethiopia. It could be attributed to global and national economic crises and price changes.
Establishment activities
  1. Land preparation (Timing/ frequency: Dry season)
  2. Planting (Timing/ frequency: Sow the green manure seeds during the short rainy season in March/April, about 45-60 days before planting the main crop.)
  3. Slash and plowing over (Timing/ frequency: Plow in the green manure about 2 weeks before planting the main crop, i.e. in June/July.)
Establishment inputs and costs (per 1.5 Sanga)
Specify input Unit Quantity Costs per Unit (ETB) Total costs per input (ETB) % of costs borne by land users
Labour
Land preparation PDs 3.0 200.0 600.0 100.0
Slashing and plow over PDs 1.5 200.0 300.0 100.0
Planting PDs 1.5 200.0 300.0 100.0
Plant material
Green manure seed kg 37.5 8.0 300.0
Total costs for establishment of the Technology 1'500.0
Total costs for establishment of the Technology in USD 28.24
Maintenance activities
  1. Labor for land preparation, planting, and slashing over. (Timing/ frequency: Before planting the main crop.)
Maintenance inputs and costs (per 1.5 Sanga)
Specify input Unit Quantity Costs per Unit (ETB) Total costs per input (ETB) % of costs borne by land users
Labour
Land preparation, planting, slashing and plow over PDs 4.5 200.0 900.0 100.0
Plant material
Seeds PDs 37.5 8.0 300.0 100.0
Total costs for maintenance of the Technology 1'200.0
Total costs for maintenance of the Technology in USD 22.59

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
Receives rainfall with a summer maximum. January to March is a dry season. The area receives short rains from March to April and maximum rain from June to September.
Name of the meteorological station: Bedele
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: surface water
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
x
good
education

poor
x
good
technical assistance

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

poor
x
good
markets

poor
x
good
energy

poor
x
good
roads and transport

poor
x
good
drinking water and sanitation

poor
x
good
financial services

poor
x
good
None

poor
x
good
Comments

Apart from electricity, the land user is closer to other public facilities and services.

Impacts

Socio-economic impacts
Crop production
decreased
x
increased

crop quality
decreased
x
increased

product diversity
decreased
x
increased

land management
hindered
x
simplified


It improves the organic matter content of the soil.

drinking water availability
decreased
x
increased

drinking water quality
decreased
x
increased

expenses on agricultural inputs
increased
x
decreased

farm income
decreased
x
increased

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

health situation
worsened
x
improved

SLM/ land degradation knowledge
reduced
x
improved


As it is evidence based practice, it improves land users knowledge about SLM.

Ecological impacts
water quantity
decreased
x
increased

water quality
decreased
x
increased

surface runoff
increased
x
decreased

excess water drainage
reduced
x
improved

groundwater table/ aquifer
lowered
x
recharge


There is no facts to validate regarding the status of groundwater table.

soil moisture
decreased
x
increased

soil cover
reduced
x
improved

soil loss
increased
x
decreased

soil accumulation
decreased
x
increased

soil crusting/ sealing
increased
x
reduced

soil compaction
increased
x
reduced

nutrient cycling/ recharge
decreased
x
increased


It improves soil nutrient cycling through adding more nutrients including by fixing atmospheric nitrogen.

soil organic matter/ below ground C
decreased
x
increased

acidity
increased
x
reduced

vegetation cover
decreased
x
increased

biomass/ above ground C
decreased
x
increased

plant diversity
decreased
x
increased

beneficial species (predators, earthworms, pollinators)
decreased
x
increased

habitat diversity
decreased
x
increased

pest/ disease control
decreased
x
increased

emission of carbon and greenhouse gases
increased
x
decreased


Part of the plow over, remains undecomposed in the soil system and contributes to carbon sequestration.

Off-site impacts
water availability (groundwater, springs)
decreased
x
increased


Off-site water availability is expected to increase but the assumption needs long-term data and documentation.

reliable and stable stream flows in dry season (incl. low flows)
reduced
x
increased

downstream siltation
increased
x
decreased

impact of greenhouse gases
increased
x
reduced

Cost-benefit analysis

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

Long-term returns
very negative
x
very positive

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

Long-term returns
very negative
x
very positive

The technology needs land users knowledge and skills and less of financial expenses.

Climate change

Gradual climate change
annual temperature increase

not well at all
x
very well
annual rainfall decrease

not well at all
x
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%
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
  • Improve soil fertility.
  • Reduce soil acidity.
  • Increase grain yield.
Strengths: compiler’s or other key resource person’s view
  • It stops the soil from being carried away by wind and rain by providing ground cover during early season when flash rain/wind causes erosion.
  • Increases soil microbial activity, and the availability of macro and micronutrients in forms that the plants can use.
  • After the plow over, most nutrients are then readily available to a new crop.
Weaknesses/ disadvantages/ risks: land user's viewhow to overcome
  • Labor demanding for establishment and maintenance. Continues awareness raising work regarding the indirect benefits generated from the technology in terms of amending the soil fertility and reducing issues of soil acidity.
  • Lack of tangible benefit as most farmers expect yield. Convince the land users about the indirect benefit accrued from using green manure.
Weaknesses/ disadvantages/ risks: compiler’s or other key resource person’s viewhow to overcome
  • Farmers may be unwilling to put in the labor or buy the seed needed. Advocate the sustainable benefits triggered by using green manures so that the mindset of the land users would be changed.
  • Lack of awareness of green manuring as a soil fertility management option since it is a recent innovation in Ethiopia. Create more awareness and institutionalize its benefit in the mainstream agricultural extension system to reach out to large number of beneficiaries.
  • Many farmers look for an immediate economic product, such as grains, from any crop that is grown. Again, this need familiarizing the land users to the in kind benefits accrued from the application of green manure. Demonstrating the technology and arranging experience exchange visit is pivotal to scale out the technology/practice.

References

Compiler
  • GERBA LETA
Editors
  • Noel Templer
  • Julia Doldt
  • Kidist Yilma
  • Tabitha Nekesa
  • Ahmadou Gaye
  • Siagbé Golli
Reviewer
  • William Critchley
  • Rima Mekdaschi Studer
  • Sally Bunning
Date of documentation: Feb. 6, 2023
Last update: April 23, 2024
Resource persons
Full description in the WOCAT database
Linked SLM data
Documentation was faciliated by
Institution Project
Key references
  • Managing Land: A practical guidebook for development agents in Ethiopia. 26. RELMA & MARD. 2005.: It is public resource.
Links to relevant information which is available online
This work is licensed under Creative Commons Attribution-NonCommercial-ShareaAlike 4.0 International