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In field In field Rainwater Harvesting for Rainwater Harvesting for Improved Maize Production Improved Maize Production

(Synthesis Results – Lessons & Challenges)(Synthesis Results – Lessons & Challenges)

By

Mário Chilundo & Paiva MunguambeMário Chilundo & Paiva Munguambe

UEM-FAEF

Final Scientific Workshop

JHB, 15-18th June 2009

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Main Objective of the trialsMain Objective of the trials

Increase water availability for crop growth

though in field water harvesting technique

RWH principleRWH principle

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RWH principle…RWH principle…

Chókwè

Semi-Arid region

October to March: rainy season with 75 % of the annual rain;April to September: dry season with 25 % of the annual rain.

Chókwè’s average annual rainfall: 582.0 mm

Introduction…Introduction…Introduction…Introduction…

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Balanço hídrico(Pr-ETc)

Water balance (Pr-ETc)Water balance (Pr-ETc)Water balance (Pr-ETc)Water balance (Pr-ETc)

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Study area Study area

Chókwè

MethodologyMethodology

• On station trials (EAC)

• Design: RCBD

• Crop: Maize (Matuba: 120 days; Potential yield: 5-6 ton/ha)

• Seasons (2006/07; 2007/08 and 2008/9)

• Mulch: 20 ton/ha (vegetable residues)

• Rain gauge: Precipitation

• Parameters: plant height and grain yield

RWT principle RWT principle • RWT: Catchment area covered by PVC plastic

• Ratio: control S80 (80*30 cm; 1:1); S160 (160*30 cm; 1:2) and

S240 (240*30 cm; 1:3) – 8 rows/plot (6 effectives+ 2 border)

Cropping Area (CA)

80X30 cm

Catchment Area (CTA)

160X30 cm

Ratio (CTA/CA) = 2:1

Plastic cover

Trials…Trials…

Maize grain yield (ton/ha)Maize grain yield (ton/ha)

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a

a

B

A b

C

2007/08

Total of 392 mm

2008/09

Total of 471.1 mm

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Results (WUE – Water Productivity)Results (WUE – Water Productivity)

Estimated Costs (500 mEstimated Costs (500 m22 plot) plot)

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   Quantity Costs (USD)

Activity Unity Control (1:1) T2 (2:1) T3 (3:1) Control 

(1:1) T2 (2:1) T3 (3:1)

PVC Plastic m - 204 156 - 306 312

Seeds kg 2 0.5 0.3 2 0.5 0.3

Sowing Unity 1 1 1 15 10 5

Weeding Unity 3 1 1 45 15 15

Total         62.0 331.5 332.3

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Ratios 1:2 (S160) and 1:3 (S240) increased water availability for

the crop, resulting in higher grain yields per plant and thus

increase WUE;

Climate change vs rainfall patterns vs sowing dates need to be

addressed because they will have impact on the yields;

Need to test other “local” material as alternative due to high

investments costs (plastic) ;

Need to consider IPDM and fertilizers to increase water

productivity and yields

Final remarks/challengesFinal remarks/challengesFinal remarks/challengesFinal remarks/challenges

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OBRIGADOOBRIGADO