Mali

1. TRADITIONAL TECHNIQUES ON THE DOGON PLATEAU

FIG 14: STONE LINES

1. STONE LINES

How They Work

• The idea of stone lines is to slow runoff and reduce erosion.

Location and Construction

• Stone lines are used very widely, on cultivated land and also barren land which is to be used in future where the slopes are shallow and where stones are available.

• Stone lines are placed approximately across the slope. Distance between the lines depends on availability of stones.

Measurements and Labour:

• The structures often consist of just a single line of large stones, of 20-30 cm height.
• No estimates of labour requirements are available.

Improvements Possible

• Possible improvements include placing the lines on the contour, and building them slightly higher, and more carefully to avoid runoff forming small rills between them. A small foundation trench would also improve their effectiveness.

2. EARTH MOUNDS

How They Work

• The small mounds dug between plants help to slow runoff as well as acting as "mini-compost heaps", improving soil fertility.

Location and Construction

• Earth mounds are used throughout the Dogon Plateau, and also elsewhere in the drier parts of Mali.

• Mounds are constructed during the first weeding in July when weeds are scraped together and covered with earth.

• The next season's seeds are planted into what remains of the mounds - where the fertility of the soil has been improved.

Measurements and Labour

• The mounds are about 20 cm high, and are spaced between clumps of plants - often about a metre apart.
• It is estimated that it takes about 10-15 person/days to form mounds on an hectare of cropped land.

FIG 15: EARTH MOUNDS

FIG 16: ONION GARDENS MADE FROM TRANSPORTED EARTH

3. ONION GARDENS made from Transported Earth

What They Are And How They Work

• Artificial onion terraces are made by the sides of watercourses where water is available, but there is no soil.

• A network of small stone squares is built on the bare rock and after being filled with earth is planted with onions or another vegetable crop.

Construction

• The stone is brought from nearby quarries if it is not available locally.
• These squares or "terraces" are then filled with earth collected from the riverbanks and carried in baskets.
• Manure is added to the earth to make it more fertile.

Planting

• Onions or other vegetables are planted in the gardens and irrigated by hand from the nearby watersource.

Measurements and Labour

• The squares have sides of about 1 - 1.5 metres, and the soil depth is initially at least 15-20 cm.

• It takes a very great deal of labour to make these gardens. One estimate is between 500 and 1,000 person/days per hectare but it may be even more if soil and rock are not available close to the water source.

FIG 17: EARTH BASINS

4. EARTH BASINS

How They Work

• The small earth basins are intended to hold all of the rainwater which falls, therefore giving complete conservation of water and soil within the field.

Location and Construction

• Earth basins are made in agricultural fields where the soils are relatively deep.

• Construction of the basins takes place during the dry season, and they are built up later when crops are weeded.

Measurements and Labour

• Basins are made in the form of squares with each side measuring between one metre and two metres in length. The basins are largest on flatter land and smallest on more sloping land.

• Each basin is surrounded by a small earth ridge, made by a hoe, of about 15 cm in height.

• This technique takes quite a large amount of work, but no accurate estimates of labour requirements are available.

2. PROJET LUTTE ANTI-EROSIVE

HOW CONSERVATION MEASURES ARE PLANNED FOR DIFFERENT LAND USE CATEGORIES

1. At the start, a cross-section or "profile" of a typical catchment in the Koutiala area was used (see fig 14) to help plan for solutions to the overall conservation problem.

2. The different land categories - plateaux, escarpments, gentle slopes etc - were then studied. From these categories, three main land use zones were identified. These zones, together with their particular problems and the technical solutions proposed are as follows:

The Cultivated Zone (a)

Location: on the gentle slopes where there are deep soils

Problems: runoff from the plateaux and escarpments causing sheet and rill erosion in agricultural fields

Conservation Techniques Recommended:

- contour stone bunds just above the fields to slow runoff from the land above
- live fences around the fields
- grass strips within the fields
- check dams made from stone or cereal stems in rills and gullies
- use of manure from the improved cattle pens in the fields - improved crop husbandry, such as tied ridging

The Protection Zone (b)

Location: the escarpments and the banks of the streams

Problems: severe erosion and deforestation

Conservation Techniques Recommended:

- protection from grazing
- revegetation with trees and grass

The Silvo-Pastoral Zone (c)

Location: the plateaux and other areas not used for cropping

Problems: lack of vegetative cover

Conservation Techniques Recommended:

- control of bush fires
- control of grazing
- control of tree cutting for fuelwood
- use of improved cooking stoves (an indirect measure)

FIG 18: PROFILE OF TYPICAL CATCHMENT (ZONES c, b & c DESCRIBED ABOVE)

FIG 19: A FLANNELGRAPH - PART OF THE "GRAAP" METHOD

3. Villagers are involved in land-use planning by means of the "GRAAP" method of interactive training. This includes the use of "flannelgraphs" where images are stuck on a felt screen.

GRASS STRIPS

How They Work

• Grass strips are a vegetative method of erosion control.
• The strips run in a straight line across the slope, within cultivated fields.
• Runoff is slowed by the strips and silt deposited.
• Technically grass strips work well, but there have been some problems including shortage of appropriate seed, and the growth of weeds within the strips.

Planting

• The grass species planted are selected for their value as fodder as well as ground cover.

• Brachiaria ruzizensis has grown well, but Pennisetum pedicellatum proved less good for ground cover or for fodder.

Where Grass Strips are Suitable

• Grass strips such as these are most suitable for the areas with above 700 mm annual rainfall, as in southern Mali.

Measurements and Labour

• The original design was for strips 5 metres wide and 50 metres apart, but farmers objected to the loss of land, so strips were reduced to 3 metres wide and spaced up to 100 metres apart.

• One person can plant about 10 metres of a grass strip in an hour (including ploughing).

FIG 20: GRASS STRIPS

FIG 21: LIVE FENCES

LIVE FENCES

How They Work

• Live fences are planted for two reasons:

- to protect fields from animals
- to act as a vegetative barrier to runoff

Planting

• Cuttings of Euphorbia balsimifera are planted closely together to form hedges around agricultural fields.

• Other species tested have been Balanites sp. Cajanus cajun, Ziziphus sp. and Acacia spp.

• Planting takes place before the rainy season. This is because Euphorbia cuttings prefer to be planted dry. This is an advantage because labour is available at this time.

• Hedges are planted around each farmer's land and also around individual fields within it.

Where Live Fences are Suitable

• Live fences of different Euphorbia species can be used very widely in the drylands of sub-Saharan Africa.

Labour

• One person can plant about 20 meters per hour (of Euphorbia).

Contents - Previous - Next