Sand hydroponics: An alternative technology for pre basic potato 

seed production.

By Daniel G. Mbiri  CIP SSAd.mbiri@cgiar.org

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IntroductionIn sub‐Saharan Africa just like the other humid tropical areas   Ralstonia solanacearum poses a serious challenge to potato  seed production. There has been an increase in consumption of potatoesOne strategy for overcoming this challenge was toincrease area under production and yields per unit areaCIP intervened through introduction of aeroponics technology in the year 2008 under the 3G technologyAeroponics technology revolutionized production of pre basic  seeds in sub‐Saharan Africa

Aeroponics requires constant supply of electricityIn many Sub Saharan Africa countries there isunreliable supply of electricity and man powerSand hydroponics offers an alternative technology forclean pre basic potato seeds productionSand hydroponics uses ordinary sand sterilized withordinary sodium hypochlorite bleachAn elevated tank is used for the flow of nutrientssolution by gravity.

Sodium hypochlorite bleach is cheaper thansteam boilers based technologySand hydroponics offers an alternativetechnology for clean pre basic potato seedsproduction.Materials and methodsThe screen houseSand hydroponics technology is screen housebased technology. The screen house must havea water proof roof

Sketch of simple screen house Sand hydroponics unit

Water sourceA dependable source of clean water should be convenient.A pH meter and an electric conductivity (EC) meter can beused for monitoring EC and pH of the waterSandSand that is too fine is not convenient as it compacts andlimits root development.Sand recycling

Sand can be recycled after one harvest. Ones through withharvest, all organic material (roots, stems, tubers) are removedand bleach is used just like on fresh sand.

Nutrient solutionGreenhouse grade fertilizers are used. The following canconstitute 1000 Liters tank:

1.potassium phosphate 136 g

2. Calcium Nitrate 236 g

3. Potassium nitrate 504 g

4. Magnesium Sulphate 100 g

5. Microsol B 12 g

Results and discussions (season one)

Clone Tubers per plant

Tube per M2

381381.13 Box 6 431

Local variety

Box 4.4 320

Local Variety

pots 19.9 550

• An intermediate technology• In Sub Saharan Africa electricity supply is still low compared to western developed economies. Sand hydroponics promises an intermediate technology .

• Economically feasible• The use of easily available timber and sand makes sand hydroponics a technology of choice for seed production in sub‐Saharan Africa

• Environmentally friendly• Potato plants  from sand hydroponics are grown on sterile substrate and there is no effluent discharged into the environment

• Simplicity of the technology• Sand hydroponics is so simple that any rural group can implement on simple wooden boxes or pot

• Simplicity

• Costs Comparison of production costs per season

GREENHOUSE SYSTEM INITIAL COST ($) COST/SEASON ($)

Aeroponics 3,543.21 2,273.32

Sand hydroponics ‐

beds

2,768.45 1,364.44

Sand hydroponics ‐

pots

908.04 878.41

Conventional ‐beds 13,308.81 1,795.82

Conventional ‐pots 10,556.84 1,039.42

• Conclusions• Sand hydroponics is the technology of choice in sub‐Saharan Africa

• To meet the increased demand for clean seeds Sand hydroponics is the way forward

• Sand culture is one of the most efficient and cost‐effective methods of soilless culture

• Sand hydroponics is new in the region and there are prospects of replicating it to many community groups and institutions within sub‐Saharan Africa.

Recommendations• Sand hydroponics technology to be replicatedin other countries

• Research works on side effects of sodiumhypochlorite to be carried out

• Research work on the number of times sandcan be recycled

• Both aeroponics sand hydroponics should beimplemented simultaneously in SSA

THE END