General information
Name of best practice	Zai; Saai (Burkina Faso); Tassa (Nigeria, Morocco, Sudan); conservation farming (Zambia)
Geographic distribution (countries)	North + West Africa
Origin of practice		indigenous/traditional or 100+ yrs old
		traditional, but improved
		recently introduced
		new technology
For what type of land use		livestock/fish farming
		cropping
		ecosystem conservation
Main purpose		water availability
		nutrient availability
		soil conservation
		others (please specify):

 

Type / Description of practice
Short description of practice (if possible with figures/drawings/photo)	The "zaï" is a traditional SWC technique developed in the extreme north of Burkina Faso (province of Yatenga) where the average annual rainfall in 1973-1995 was only 562 mm and where the soils are heavily encrusted. The "zaï" is usually a “hole” or “basin” with a diameter of 20-30 cm and depth of 10-15 cm (Wright, 1982); their dimensions vary according to the types of soil in which they are dug. They are often larger in lateritic soils, which have a limited water retention capacity, than in clay soils which are less porous. The number of "zaï" per hectare depends on the distance between them, and usually varies between 12,000 and 15,000. The holes are above all used to rehabilitate the lateritic and sandy-clay soils that the Mossi call "zippelle" ("clearing" or "bare soil") and are dug during the dry season (November to May).
	The  holes/depressions in crusted soils at intervals of one to five meters and partly inserting a mixture of organic matter and soil back into the hole.  Seeds of crops or whole crop plants are then placed in the depressions.  Runoff from the crusted soils will tend to infiltrate into the depressions and the depressions will consequently become microsites of greater soil water content.  The depressions will also have a greater nutrient status due to the addition of organic matter.  Where goats or game may threaten the crops, spiny shrubs are often planted together with the crop plant.  The spiny shrubs then protect the crops from browsing.  The layout of a protected Zai is illustrated in Fig. 2.
From Paul BANDRE , Fatoumata BATTA1998: Soil and Water Conservation (SWC) in Burkina Faso, Voisins Mondiaux Siege Pour L’afrique De L’ouest, p. 18ff	Left picture from Coffey, 2002 Zai  rehabilitation using spiny shrubs to protect crop plants from herbivores (picture Mills).  It takes about 60 days to dig the "zaïs" in a one (1) hectare field. During the dry season the "zaïs" collect the leaves, twigs and fine sand carried by the wind. Farmers also put a handful of manure in the holes to attract termites which dig underground galleries that facilitate the deep infiltration of rainwater and runoff. The termites not only improve the porosity and water retention capacity of the soil, they also bring other nutrients from the deeper layers of soil to the surface horizons and vice-versa. These "zaïs" are effective because they concentrate water and manure at the same point (Mathieu Ouédraogo and Vincent Kaboré, 1996). In a year of normal rainfall, the yields of sorghum and millet (using the "zaï" system for the first time) vary between 500 and 1,000 kg/hectare. The biomass produced varies between 2 and 4 tonnes of sorghum and millet stems. During the second year of the "zaï" system, the farmers sow their seeds in the existing holes or, if there is enough space between the holes, they dig new holes. After 5 years, the entire cultivated surface has been improved by the "zaïs" and the action of the termites (Roose et al., 1994).

 

Natural resources prerequisites
Soil	particularly encrusted bare soils	Relief	flat to slightly sloopy
Climate	rid	Vegetation	degraded
Other prerequisites		Supply of organic matter (e.g. vegetable skins, leaves, grass, dung)
Time requirements to restore land/water/nutrients		2- 5 years
Reference level in this comparison		Crusted bare soil

 

Socio-economic factors / prerequisites
Land ownership/tenure		- -
Farm sizes		1 to 2 ha
	Supports shifting cultivation			Supports rangeland management
	Supports sedentary farming			Supports uncontrolled grazing
	Supports livestock production			Supports others (please specify):
	Transhuman system
Usually requires credit			no		yes
Machine requirements:			no		yes (name what), specify
Labour requirements:			hired		family labour
Investment phase: It takes about 60 days to dig the "zaïs" in a one (1) hectare field.			high		moderate		low
Maintenance:			high		moderate		low
Do quantifications exist? (give data or reference)  from Kabore & Reij, 2004
Requires/supports division of labour (gender, age, ethnic group ...).			no		yes (name what), specify
			Hard work, often performed by men
Requires/supports participation of communities (e.g. joint field preparation):		Joint field preparation

 

Advantages of the practice
Yields, profit	increase of yield
Biophysical	increase of infiltrations; particularly important in encrusted soil; increases soil nutrient status
Labour economic	If the practice is financed, labour will be required to create holes/depressions
Socio-cultural, religious	- -
Skill/knowledge requirements	Some ecological and horticultural expertise in terms of knowing when to plant crops and which spiny bushes can be cultivated effectively
Ecological (on-site, off site)	positive effect on diversity of soil biota
Others (please specify)	- -

 

Disadvantages / Constraints of the practice
Yields, profit	- -
Biophysical	- -
Labour economic	labour intensive
Socio-cultural, religious	- -
Skill/knowledge requirements	- -
Ecological (on-site, off site)	- -
Others (please specify)	- -

 

Dissemination
Dissemination		was/is a success - Well known in western Africa, dissemination, among others, by NGOs. No own experience
		was/is slow
		still in test stage
If successful for new technologies: Was it so far		“early adoption” (curiosity, testing)
		“verified adoption” (farmers repeat practice still in third year)
Any data/reference on adoption and dissemination (where, how many farmers/ rangers/ herdsmen):	from Kabore & Reij, 2004
If disseminated, then how		Farmer-Farmers		Media
was it done?		Extension service		Research project
		Others (specify)
If via research, was it		Technology Transfer		Participatory On-farm Research
If via research/ extension or others, was it		free or with incentives		without incentives
Name at least 2-3 crucial conditions for successful adoption by farmers
A crusted bare soil surface is present and limits crop production/browsing potential. A supply of organic matter is available. Rainfall is intense enough to guarantee some runoff and thereby enable flow into depressions Credit required by  farmers to hire labour Secured land rights Availability of market for output
Who adopted it (describe typical adopters)?	- -
In which region(-s)?	Western Africa
Name at least 2-3 important dissemination/adoption constraints/blocker.
Livestock densities are so great that all green material will be consumed before spiny shrub seedlings are able to grow into large plants that can protect crops from herbivores. Rainfall is too erratic to enable plant establishment. A supply of organic matter is not available (possibly because all organic matter is utilised for fuel). Length of time required to make zai
Who did not adopted it (describe typical non-adopters)?	Crop/Livestock farmers
In which region(-s)?	North Africa and the Sahel

 

Evaluation
How was its restoration ability evaluated so far?		on station		on farm
References, if known:	- -
How could remote sensing/ GIS contribute to monitor restoration success?	The prerequisites concerning soil characteristics, precipitation as well as population density (labour availability), market distance etc. can be used to identify possible areas of extension. Below a study from Freeman who concluded that circumstances in the Yatenga region of Burkina Faso were unique.
from Freeman,  1999
How could adoption and dissemination be improved?
Financing could be supplied to implement ‘saai’ and demonstrate to locals the effectiveness of the practise. Research could be conducted to determine which spiny shrubs are most suitable for protecting crop
Rank three crucial research needs.
1.	Selection and preparation of substrate
2.	Inoculation with appropriate biota: e.g., termites, isopods, earthworms (sub-humid areas)
3.	Use of mycorrhiza and rhizobia
4.	the technology is seen to be coupled profitably with ReviTec
Key literature on the practise (biophysical as well as socio-economic)	Paul BANDRE , Fatoumata BATTA 1998: Soil and Water Conservation (SWC) in Burkina Faso, Voisins Mondiaux Siege Pour L’afrique De L’ouest,   Mando, A., Brussaard, L. & Stroosnijder, L. 1999. Termite- and mulch-mediated rehabilitation of vegetation on crusted soil in West Africa. Restoration Ecology 7: 33-41. Fatondji, D., Martius, C. & Vlek, P. 2001. Zai - A Traditional Technique for Land Rehabilitation in Niger. ZEFnews 8: 1-2. Barry, B. and M. Sonour (2003). Best practices in rainfed agriculture in West Africa. Proceedings of the Symposium and Workshop on Water Conservation Technologies for Sustainable Dryland Agriculture in Sub-Saharan Africa (WCT), held at Bloem Spa Lodge and Conference Centre, Bloemfontein, South Africa, 8-11 April 2003. Pretoria, South Africa: ARC-Institute for Soil, Climate and Water. pp.60-74 [ShelfMark - IWMI 631.7.1 G100 BEU] (H 34389).          Coffey, A. (2002). The role of indigenous knowledge in determining design and the planning of water harvesting systems. Kaboré, D. and C. Reij (2004). The emergence and spreading of an improved traditional soil and water conservation practice in Burkina Faso. EPTD Discussion Paper No. 114. E. a. P. T. D. I. F. P. R. Institute. Washington, International Food Policy Research Institute: 28.        Mati, B. M. and M. Lange (2003). Emerging practices in water management under rainfed agriculture in eastern Africa. Proceedings of the Symposium and Workshop on Water Conservation Technologies for Sustainable Dryland Agriculture in Sub-Saharan Africa (WCT), held at Bloem Spa Lodge and Conference Centre, Bloemfontein, South Africa, 8-11 April 2003. Pretoria, South Africa: ARC-Institute for Soil, Climate and Water. pp.60-74 [ShelfMark - IWMI 631.7.1 G100 BEU] (H 34389). Roose, E. 2002. Traditional strategy for soil and water conservation in Mediterranean area.  European Society for Soil Conservation. Third International Congress, Man and Soil in the Third Millenium, Book of abstracts: http://www.zalf.de/essc/valindex.htm#indexval  Réseau Erosion, Centre IRD-ORSTOM, BP.4045, F 34032 Montpellier, France. Tel: (33) 467 41 62 65. Fax: (33) 467 41 62 94. E-mail: Eric.Roose@mpl.ird.fr Freeman, P. 1999: Mapping the Range of Proven Soil Management Practices in Africa. http://www.devecol.org/DevecolAfrica/Library/SWCextrapol.PDF
Submitted initially by	Hartmut Koehler/Anthony Mills/Katrin Vohland