Technologies

Conservation Agriculture in a semi-arid area [Namibia]

Lima nawa (Vambo/Rukwangali)

technologies_1297 - Namibia

Completeness: 80%

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:
SLM specialist:

Simfukwe Maxon

CEDP

SLM specialist:

Kowalski Benjamin

Germany

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)
Book project: Making sense of research for sustainable land management (GLUES)
Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)
The Future of Okavango (TFO / GLUES)

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

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

No

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

Conservation agriculture using permanent water-harvesting planting basins, or rip-lines and fertilizer/manure application on low fertility dryland soils.

2.2 Detailed description of the Technology

Description:

Farmers in north-eastern Namibia practice shifting/semi-permanent subsistence cropping, concentrating on pearl millet cultivation. Here, conservation agriculture (CA) was promoted to sustain and improve production and to reduce conversion of woodland to crops. CA comprises the three principles of minimum soil disturbance, permanent soil cover, and rotation. CA was tested on small plots with volunteers trained by a local NGO. The technology was characterized here by: (i) Early (pre-rains) preparation of the land with two alternative techniques; either: a) basins with a defined spacing opened by a hand hoe, with composted manure added (biochar has also been tested), or b) rip-lines prepared with oxen in lines and with manure application within the rip lines; (ii) Mulching the soil with crop residues, branches or sunnhemp, specially grown for the purpose; (iii) Protection against grazing of crop and mulch by livestock; (iv) Intercropping with vegetables or legumes. (v) Weeding.

CA has been promoted for four seasons, and now trained farmers are transferring their knowledge to others. The technology was promoted to substantially improve the low yields of traditionally practiced agriculture by improving fertility and soil structure as well as better capturing runoff. It was also aimed at avoiding further expansion of croplands into dry woodlands on low fertility arenosols. Eventually it is hoped that the well-being of local subsistence cropping communities will be improved and outmigration reduced.

Knowledge about CA comes from Zambia, where it has been has been practiced successfully for many years by small-scale farmers. A local NGO was engaged by an international project (www.future-okavango.org) which searched for volunteer farmers in the Kavango area. The first CA planting took place in 2011/12. These pioneer farmers were backstopped regularly and the number of farmers trained increased. The NGO monitored crops with contact farmers. 45 more farmers showed interest and were then trained by the contact farmers. Training and backstopping continued until August 2015.

The natural environment is semi-arid. Rainfall is concentrated from November to March. Mean annual precipitation is 570 mm, and mean air temperature is 26.2°C in the hottest month (October) and 16.2°C in the coldest month (July). The landscape forms part of the extended Kalahari basin in central-southern Africa. Deep and extended sands restrict people to living in areas close to surface water. Villages are located along the Okavango on the elevated river terraces – where they produce crops. Here, sedimentation of fine-grained soils, the accumulation of calcium carbonates in the subsoil and the activity of termites have resulted in soils of medium fertility which could potentially ensure yields of 500 kg/ha of millet, if well managed, and assuming good rainfall. Due to the growing population and restricted land availability, cultivation patterns have changed from shifting to semi-permanent and expanded to the adjacent woodlands on the deep Kalahari sands. Here, rapid degradation of soil fertility has caused further expansion and reduced crop yields to very low levels (ca. 150 kg/ha on average). Livestock graze and browse vegetation on the floodplains and in the woodlands. Due to night-time kraaling of livestock, manure is available as fertilizer: thus sustained cropping can be supported. The importance of the woodlands for ecosystem services including timber and firewood, for thatching grass, medicinal plants and biodiversity means they must be conserved and this acts as a reason to support the search for alternative crop production systems such as CA.

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:

Namibia

Region/ State/ Province:

Kavango East

Further specification of location:

Mashare

Specify the spread of the Technology:
  • evenly spread over an area
If precise area is not known, indicate approximate area covered:
  • < 0.1 km2 (10 ha)
Comments:

Boundary points of the Technology area: -17.92 / 20.0 -17.89 / 20.28
SLM technology was applied by trained smallholders on small plots

2.6 Date of implementation

If precise year is not known, indicate approximate date:
  • less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:
  • through projects/ external interventions
Comments (type of project, etc.):

Introduction in the area by Community Economic Development Programme (CEDP) TFO-project in 2011

3. Classification of the SLM Technology

3.1 Main purpose(s) of the Technology

  • improve production
  • reduce, prevent, restore land degradation
  • conserve ecosystem

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

Land use mixed within the same land unit:

Yes

Specify mixed land use (crops/ grazing/ trees):
  • Agro-pastoralism (incl. integrated crop-livestock)

Cropland

Cropland

  • Annual cropping
Number of growing seasons per year:
  • 1
Specify:

Longest growing period in days: 135, Longest growing period from month to month: Nov to March

Grazing land

Grazing land

Extensive grazing:
  • Semi-nomadic pastoralism
Comments:

Major land use problems (compiler’s opinion): Low and very variable yields per ha; ongoing expansion of fields to less fertile woodlands due to nutrient depletion of originally fertile plots; years with dry spells.
Major land use problems (land users’ perception): Crop wilting and poor yields, opening new areas in search of better fields, cutting down trees, slushing and burning residues
Type of cropping system and major crops comments: Under CA, sunhemp for residue and nitrogen fixing has been grown as green manure and fodder for livestock.

Livestock density: 1-10 LU /km2

3.4 Water supply

Water supply for the land on which the Technology is applied:
  • rainfed

3.5 SLM group to which the Technology belongs

  • integrated soil fertility management
  • cross-slope measure
  • water harvesting

3.6 SLM measures comprising the Technology

agronomic measures

agronomic measures

  • A3: Soil surface treatment
management measures

management measures

  • M2: Change of management/ intensity level
Comments:

Type of agronomic measures: early planting, mixed cropping / intercropping, mulching, green manure, legume inter-planting, manure / compost / residues, rotations / fallows, minimum tillage, pits

3.7 Main types of land degradation addressed by the Technology

chemical soil deterioration

chemical soil deterioration

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

biological degradation

  • Bc: reduction of vegetation cover
  • Bf: detrimental effects of fires
  • Bl: loss of soil life
Comments:

Main causes of degradation: soil management (Missing nutrient returns)
Secondary causes of degradation: over-exploitation of vegetation for domestic use (Grazing and burning of crop residues), population pressure (Expansion of croplands to less fertile soils)

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):

Scheme of CA field with basins
Within the fenced area, basins are dug per hand-hoe in lines with about 15 cm width, 35 cm length and 15 cm depth and in 70 cm distance. To keep the line and position, a rope with knots every 70 cm is used. Each basin is refilled with 2 cans of manure mixed with part of the soil material. Maize or pearl millet - two stages shown on the graph
Location: Mashare. Kavano East/Namibia

Technical knowledge required for field staff / advisors: moderate
Technical knowledge required for land users: low
Main technical functions: increase in nutrient availability (supply, recycling,…)
Secondary technical functions: increase / maintain water stored in soil, increase of biomass (quantity)

Early planting
Remarks: Planting basins prepared in dry season, planting can occur by first rainfalls (earlier than plough-d

Mixed cropping / intercropping
Material/ species: Maize / Millet /Cowpea
Remarks: Cultivated in parallel lines

Mulching
Material/ species: Grasses & crop residues & sunhemp
Remarks: sunhemp cultivated on the CA field and cut to produce mulch

Green manure
Material/ species: branches of fertilizer tree

Manure / compost / residues
Material/ species: Composted manure from cattle post

Rotations / fallows
Material/ species: Maize / Millet /Cowpea
Remarks: Planted in lines and shifted annually

Minimum tillage
Material/ species: Riplines by oxen

Pits
Material/ species: planting basins by hand hoe

Retention/infiltration ditch/pit, sediment/sand trap
Spacing between structures (m): 0.7
Depth of ditches/pits/dams (m): 0.15
Width of ditches/pits/dams (m): 0.15
Length of ditches/pits/dams (m): 0.35

Structural measure: ripline
Spacing between structures (m): 0.7
Depth of ditches/pits/dams (m): 0.25
Width of ditches/pits/dams (m): 0.1

For water harvesting: the ratio between the area where the harvested water is applied and the total area from which water is collected is: 1:8,3
Change of land use practices / intensity level: More specific soil management; crop protection by fencing; earlier seeding
Major change in timing of activities: To a large part, land preparation can be carried out throughout dry season, independent of rainfall level

Author:

Maxon Simfukwe

4.2 General information regarding the calculation of inputs and costs

other/ national currency (specify):

Nam $

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

15.5

4.3 Establishment activities

Activity Timing (season)
1. dry season

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 1104.0 1104.0 100.0
Construction material Wire for fencing ha 1.0 224.0 224.0 100.0
Construction material sticks & poles ha 1.0 1114.0 1114.0 100.0
Total costs for establishment of the Technology 2442.0
Total costs for establishment of the Technology in USD 157.55
Comments:

Duration of establishment phase: 3 month(s)

4.5 Maintenance/ recurrent activities

Activity Timing/ frequency
1. Repairing fences and de-bushing of the fields (May - July)
2. Gatering and spreading of mulch cover July - Dec
3. Cutting sunhemp and applying as additional mulch Feb-Mar
4. Re-digging the planting basins August
5. Manure collection, Planting & fertilizer application September - December
6. Sowing of main crops and sunnhemp and fertilizer application November - December
7. Intercropping with legumes like groundnuts and cowpeas normally two weeks after germination of cereals.
8. Weeding
9. Harvesting April - May

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 1.0 848.0 848.0 100.0
Plant material seeds ha 1.0 22.0 22.0 100.0
Fertilizers and biocides fertilizer ha 1.0 159.0 159.0 100.0
Fertilizers and biocides compost/manure ha 1.0 276.0 276.0 100.0
Construction material Wire for fencing ha 1.0 220.0 220.0 100.0
Total costs for maintenance of the Technology 1525.0
Total costs for maintenance of the Technology in USD 98.39
Comments:

Machinery/ tools: Values above are for manual CA using a hoe; an external worker earns 4 N-$ per working hour; above, family labour was multiplied by 4 to estimate the “value” of the family labour invested
The costs are based on labour needs of one year and 500 kg/ha of fertilizer

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

CA was designed to require minimal financial investments; theoretically, everything apart from wire for the fences and inorganic fertilizer can be created or gather by the household. This turns CA into a very labour intensive farming practice. The high Dollar values above result from multiplying the (free) family labour invested in farming with the typical hourly wage rate of an external worker

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

Thermal climate class: subtropics

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.

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):
  • coarse/ light (sandy)
  • medium (loamy, silty)
Topsoil organic matter:
  • medium (1-3%)
  • low (<1%)

5.4 Water availability and quality

Ground water table:

5-50 m

Availability of surface water:

poor/ none

Water quality (untreated):

good drinking water

5.5 Biodiversity

Species diversity:
  • medium

5.6 Characteristics of land users applying the Technology

Market orientation of production system:
  • subsistence (self-supply)
Off-farm income:
  • 10-50% of all income
Relative level of wealth:
  • poor
  • average
Individuals or groups:
  • individual/ household
Level of mechanization:
  • manual work
  • animal traction
Gender:
  • women
  • men
Indicate other relevant characteristics of the land users:

Land users applying the Technology are mainly common / average land users
Population density: 10-50 persons/km2
Annual population growth: 1% - 2% (One farmer to our knowledge could be considered wealthy). (Few average farmers). (Mostly CA farmers are poor).

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
Is this considered small-, medium- or large-scale (referring to local context)?
  • small-scale

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

Land ownership:
  • state
  • communal/ village
Land use rights:
  • communal (organized)
Water use rights:
  • communal (organized)
Comments:

parallel existence of state and communal laws

5.9 Access to services and infrastructure

health:
  • poor
  • moderate
  • good
education:
  • poor
  • moderate
  • good
technical assistance:
  • poor
  • moderate
  • good
employment (e.g. off-farm):
  • poor
  • moderate
  • good
markets:
  • poor
  • moderate
  • good
energy:
  • poor
  • moderate
  • good
roads and transport:
  • poor
  • moderate
  • good
drinking water and sanitation:
  • poor
  • moderate
  • good
financial services:
  • poor
  • moderate
  • good

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

crop production

decreased
increased
Income and costs

expenses on agricultural inputs

increased
decreased
Comments/ specify:

not measured but assumed

farm income

decreased
increased

workload

increased
decreased
Comments/ specify:

not measured but assumed

Socio-cultural impacts

food security/ self-sufficiency

reduced
improved

health situation

worsened
improved

cultural opportunities

reduced
improved

recreational opportunities

reduced
improved

conflict mitigation

worsened
improved
Comments/ specify:

Envy and gossip were observed

situation of socially and economically disadvantaged groups

worsened
improved

contribution to human well-being

decreased
increased
Comments/ specify:

Improved and stabilized yields help rural families to adapt to modern lifestyles. However, the long-term contribution of CA to the well-being of the local farmers cannot be foreseen. The establishment of family-owned fenced areas for crop production is likely to have an influence on the social structure of the rural communities.

Ecological impacts

Water cycle/ runoff

evaporation

increased
decreased
Comments/ specify:

not measured but assumed

Soil

soil moisture

decreased
increased
Comments/ specify:

not measured but assumed

soil cover

reduced
improved
Comments/ specify:

not measured but assumed

nutrient cycling/ recharge

decreased
increased
Comments/ specify:

not measured but assumed

soil organic matter/ below ground C

decreased
increased
Comments/ specify:

not measured but assumed

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Climate-related extremes (disasters)

Climatological disasters
How does the Technology cope with it?
drought well
Comments:

Dig basins at 20cm (0.20m) deep; and extra water harvesting basins at 0.45m in-between the rows. For the ox-ripped lines, use ripper wings to open a wider farrow for water harvesting

6.4 Cost-benefit analysis

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

slightly negative

Long-term returns:

positive

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

neutral/ balanced

Long-term returns:

positive

6.5 Adoption of the Technology

Comments:

SLM Technology has been applied by own interest of smallholders
100% of land user families have adopted the Technology without any external material support
There is a strong trend towards spontaneous adoption of the Technology

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Saves labour over time
Can use less land compared to conventional system for the same harvest/yield
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
A strength of the system is the timely land preparation
The advantage of permanent planting stations results from the higher availability of nutrients to crop roots.
The moisture retention within the rooting space is improved by the surface structure and the increase in soil organic matter
The rotations of crop rotations is encouraged
All inputs can be used precicely, there is less wastage of inputs

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?
The weed management is labour intensive and the impact of pests might be a future challange. The application of more mulch and the weeding regularly in the first part of the season is supposed to reduce weeds.
Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
To start with this technology is labour intensive at the beginning. In this moment, the hard pan caused by years of ploughing has to be loosened. Because the basins/riplines are permanently maintained in CA, the preceding land preparations become easier. Also since land preparation starts before on-set of rains, one can spread labour by starting just after harvesting crop
There is a general problem of constructing fences around fields in communal lands, as state authorities declare this land as being owned by the state. By agreeing with the local leadership to allow those doing CA to fence off their fields for proper keeping of residues and basins/riplines that might be prone to free livestock grazing after crop harvests.

7. References and links

7.1 Methods/ sources of information

  • field visits, field surveys
  • interviews with land users
When were the data compiled (in the field)?

01/03/2001

7.2 References to available publications

Title, author, year, ISBN:

Groengroeft, A., et al. (2013) A method for yield assessment on rainfeld dryland agricultural fields.

Available from where? Costs?

Biodiversity & Ecology 5:279 - 286

Title, author, year, ISBN:

Kowalski, B. et al. (2013) Mashare - The People.

Available from where? Costs?

Biodiversity & Ecology 5:121-128

Title, author, year, ISBN:

Pröpper, M. et al. (2010) Causes and perspectives of land-cover change through expanding cultivation in Kavango.

Available from where? Costs?

Biodiversity in southern Africa. Volume 3: Implications for landuse and management, eds. M. T. Hoffman, U. Schmiedel and N. Jürgens. Göttingen & Windhoek: Klaus Hess Publishers.

Title, author, year, ISBN:

Pröpper, M. et al. (2015) The Future Okavango – Findings, Scenarios and Recommendations for Action.

Available from where? Costs?

Research Project Final Synthesis Report 2010-2015, 190. Windhoek: University of Hamburg

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