The zaitechnique is a traditional land rehabilitation technique from Burkina Faso withthe potential to rehabilitate degraded drylands effectively and to restore soilfertility. A zai pit is a square hole 60 cm deep and 60 cm by 60 cm wide, sunkinto dry, degraded soil. It is filled with well composted manure mixed withtopsoil. There are three steps to preparing a zai pit: (i) digging the pits(dimensions depend on the type of crop to be grown); (ii) application of wellcomposted manure; and (iii) planting (done at the onset of rainfall).

The zaitechnique has been practised for many years in the Sahelian region of WestAfrica. In Kenya, trials by farmers, especially in the semi-arid areas ofMakueni, Maragua and wider Murang’a districts produced good results, showing thatthe technique has great potential for improving crop production in dry areas.Zai pits, also referred to as planting pits, increase crop yields by acombination of moisture conservation and harvesting of runoff from the spacesbetween the pits. In addition, soil fertility is restored since the manure andfertiliser cannot be lost through surface runoff. Zai pits are recommended forrelatively low rainfall areas, or where moisture conservation is desired, toenable a crop survive drought and increase production.

Scaling up approaches used

Theusers of zai pit technology are mainly small-scale farmers in arid andsemi-arid lands (ASALs). The implement manufacturers and input suppliers alsodo benefit from sales of the technology implements. The technology haspredominantly been promoted through demonstrations organised in practisingfarmers’ fields and farmer field schools. The factors critical to successfulpromotion and wider adoption are: promotion and upscaling of the technology;availing knowledge and simplified inputs; and availability of localised weatherforecasts.

Challengesencountered in further dissemination of the technology or innovation, adoptionand scaling up and out include: high labour involved in digging the pits;limited availability and knowledge of preparing well composted manure; and theright type of crops.

Severaloptions are available to scale up the benefits of this technique. These are:some scientific research to provide reliable data for the region; availinglaboratory services for testing quality of organic matter produced by farmersand for recommending correct application rates; and testing high value crops toincrease profits.

Lessonslearnt about the best ways to encourage the largest number of farmers to adoptthe zai pit technology include: specialised equipment is not required, as zaipits can be prepared using available equipment; experience showed that after afew pilot projects acceptance of the technique spreads quickly, thanks to itssimplicity and effectiveness; and farmers noted that the soil around the plantsremains damp for a considerable length of time after the rains stop.

Althoughthe zai pit technology can be labour intensive, which is disadvantageous towomen, it has been met with no reservations in the countries where it has beenintroduced. The technology has been introduced such that it is not contrary toany socio-cultural practices.

How andwhen are the zai pits prepared? Farmers dig zai pits during the dry season.they must use the specified dimensions for the size of zai pits hence thenumber of pits per hectare to get the maximum benefit in terms of amount ofwater collected in the pits. (The number of pits per hectare and theirdimensions) determine how much water they harvest. The bigger the number andthe smaller their size, the less water each pit harvests and vice versa.)

Procedure

1)   Layingout planting pit positions

§ Selecta part of the farm where the land is neither too steep nor very flat. If landis on a slope, construct terraces first. The pits must be dug at alternatepositions behind each other to allow enough catchment area from which tocollect sufficient runoff to go into each pit.

§ Startingat one end of the field use a tape measure or a marked string to fix pegs 150cm apart on the first row.

§ Measurea row spacing of 75 cm downhill.

§ Inthe 2nd row, place the first peg 75 cm from the line of the first peg.

§ Continueto place pegs 150 cm apart as with row 1, so that all the pegs in row 2 are atalternate positions behind row 1.

§ Continuemeasuring and pegging in this way until you have a network of pegs at alternatepositions.

2)   Preparationof pits

At each peg position, prepare a plantingpit measuring 60 cm deep ×60 cm diameter as follows:

§ Digholes 60 cm diameter, placing topsoil (about 20 cm depth) on the uphill side.

§ Digthe subsoil to a depth of 60 cm and place the spoil on the downhill side.

§ Reshapethis spoil to resemble a semi-circular bund to enable better water storage.

Figure 1: Zai pits prepared in the dry seasonbefore the onset of rain for planting.

3)   Manureapplication (crucial for the success of the technique)

§ Mixthe topsoil with one medium size bucket of well-composed soil organic materialin the soil originating from animal manure and plant residuals at variousstages of decomposition and reformation; it is often referred to as humus) andplaced at the bottom of the pit and not broadcasted over the whole field.

§ Ensurethat the hole is not refilled to the top so that some space remains to collectand store runoff water.

4)   Planting

§ Plantthe selected crop in the hole at onset of the rain.

§ Thenumber of seeds per hole depends on crop type, its variety and climate.

§ Ifyou plant seeds in pairs, remember to thin to single plants later.

5)   Crophusbandry

Once the crop is growing in the plantingpit, the following management practices are needed:

§ Keepthe field clear of weeds. Do not use a jembe (hoe) to dig outside the pits(catchment). Clear the weeds using a panga (machete) to leave the catchmentfirm and compacted.

§ Insidethe pits, weed normally to encourage infiltration.

§ Protectthe crop from pests and diseases.

Figure 2: Maize crop planted in the holes.

Usingplanting pits has advantages and disadvantages as outlined below.

Advantages of zai pit technology

1.    Onceprepared, the pits can be re-used for up to four crop seasons without addingmore manure.

2.    Increasedcrop yield and better crop survival in time of drought. The pits can make adifference between getting a harvest or nothing at all in a low rainfallseason.

3.    Weedcontrol is easier.

4.    Waterconservation in the pit, thus reducing soil erosion on other parts of the farm.

5.    Improvedsoil fertility and environmental conservation.

6.    Theorganic material used attracts termites, which play a crucial role as they digchannels in the soil, improving the soil’s structure. The termites also digestthe organic material, making nutrients more easily available to the cropsplanted or sown in the pits.

Disadvantages of zai pit technology

1.    Akey limitation with the pits is the heavy labour demanded in preparing the pitsthe first time (between 300 and 450 hours/hectare).

2.    Theymay not work well in waterlogged soils.

3.    Mechanisationis not possible.

4.    Additionaleffort from the farmers who have to maintain the holes, by deepening andrefilling them with manure before each wet season.

Thebenefits of using planting pits far outweigh the disadvantages.

Name and contact of the organisation:

KenyaAgricultural Livestock and Research Organization (KALRO),

P. O.Box 57811-00200, Nairobi, Kenya;

Email:director@kalro.org;

Tel:+254-20-4183301- 20

Fax:+254-20-4183344;

Mobile:+254-722 206 988, 722 206 986, 733 333 223, 733 333 224

Name and address of key scientist:

Jane W.Wamuongo,

P. O.Box 57811-00200, Nairobi, Kenya;

Email:JWWamuongo@karlo.org;

Tel:+254-20-4183344;

Fax:+254-20-4183344;

Mobile:+254-722 206 988, 722 206 986, 733 333 223, 733 333 224

Name and address of key scientistsinvolved in generation of the innovation:

BarrackOkoba, KALRO-Kabete,

P. O.Box 147300-00800, Nairobi, Kenya;

Email:okoba2000@yahoo. com;

Telephone:+254-20 -4444137/144;

Fax:+254-20 -4443926

Name and contact of key partners:

KenyaInstitute of Organic Farming, c/o Michael Waweru Nduati,

P. O.Box 34972 GPO 00100;

Email: kiof@iconnect.co.ke;

Telephone:+245733799072/733817240