Prof. John AnnandaleProf. John Annandale (University of Pretoria) (University of Pretoria)

Prof. Rui BritoProf. Rui Brito (University Eduardo Mondlane) (University Eduardo Mondlane)

Dr. Martin SteynDr. Martin Steyn (University of Pretoria) (University of Pretoria)

Prof. Richard Stirzaker Prof. Richard Stirzaker (CISRO)(CISRO)

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Paiva MunguambePaiva Munguambe

WATER & NITROGEN WATER & NITROGEN MANAGEMENT ON SALT-MANAGEMENT ON SALT-

AFFECTED SOILS IN THE CHÓKWÈ AFFECTED SOILS IN THE CHÓKWÈ IRRIGATION SCHEME, IRRIGATION SCHEME,

MOZAMBIQUEMOZAMBIQUE----------------- - Progress ReportProgress Report - -----------------

Final Scientific Workshop – CP 17Final Scientific Workshop – CP 17JHB, 15 to 18 June 2009JHB, 15 to 18 June 2009

UEM/FAEF

IntroductionIntroduction

IntroductionIntroduction……

Some features of the CIS Designed in the 50s… drainage was not so relevant….!! Water from Massingir & Macarretane Dams (Gravity) HICEP…… 30,000 ha ( 1,000 ha salinazed & only 6 to 7,000 ha

effectively cultivated) 12,000 farmers (Small <4 ha; Medium 4 to 15 ha; big > 20

ha) Private company (MIA) Water Users Association Rice (summer crop) : 2 to 4.5 ton/ha Vegetables + maize (winter crops): tomatoes up to 60

ton/ha; Heavy clay soils (low infiltration & transmissivity rates) Good irrigation water ( 0.5 dS/m) Poor crop and irrigation water management (Irrigation

Efficiency < 30%) Poor infrastructure management (State & farmer's

management)

IntroductionIntroduction……

Research questions, hypotheses & objectives

(i) How to leach salts but conserve nitrogen on salt-affected soils of the CIS?

Hypothesis 1: Improved irrigation water and nitrogen management

strategies will increase water and nitrogen use efficiency

in salt-affected soils.

Hypothesis 2: Shallow water-table in salt-affected soils affects the salt

dynamics in the root zone.

Hypothesis 3: Current irrigation water management under heavy clay

textured soils with a shallow water table contributes

both to nitrogen losses and low water use

efficiency.

MethodologyMethodology

• 3 Saline Sites (Non-S, Mod-S & Saline)

• Trial Layout (2X2 Factorial; 3 Rep; CRBD):2007; 08;

09

• Wtreatments- Calendar & SWD to FC

• Ntreatments – 100 kg/ha ( 5 on/ha) & 200 kg/ha (>10 ton/ha)

• WFD – drained water (N & Salt Analysis) at depths

• Monitoring (eg., climate & parameters, yields, etc.)

• ? Modelling exercise!!?

Methodology…

Instrumentation & Monitoring

Preliminary ResultsPreliminary ResultsEC & N03 drained water (WFD): 3 Sites Dry SeasonEC & N03 drained water (WFD): 3 Sites Dry Season

Preliminary ResultsPreliminary Results……

EC & N03 drained water (WFD): 3 Sites Dry SeasonEC & N03 drained water (WFD): 3 Sites Dry Season

Preliminary ResultsPreliminary Results……

EC & N03 drained water (WFD): 3 Sites Wet SeasonEC & N03 drained water (WFD): 3 Sites Wet Season

Preliminary ResultsPreliminary Results……

EC & N03 drained water (WFD): 3 Sites Wet SeasonEC & N03 drained water (WFD): 3 Sites Wet Season

Preliminary resultsPreliminary results……

Yield (Maize PAN 67): Dry & Wet SeasonsYield (Maize PAN 67): Dry & Wet Seasons

Preliminary ResultsPreliminary Results……

Salt accumulation process: ModSaline & Saline Salt accumulation process: ModSaline & Saline SitesSites

Preliminary ResultsPreliminary Results……

Salt accumulation process – Saline & ModSaline Salt accumulation process – Saline & ModSaline sitessites

Rep

1

Rep

2

Rep

3

WT (WT (1.2 m to 0.90 m)1.2 m to 0.90 m)

Irrigation canal waterlogging

20 m20 m

Challenges & On-going Challenges & On-going ActivitiesActivities• REGIONAL & in situ HYDROLOGY AFFECTS SALT

DYNAMICS

– WHAT MODELLING APPROACH CAN BETTER SUIT?

• Modelling processes…. understanding the causes & effects (Micro

scale) …

• Modelling better future management scenarios (Macro scale) …

Water vs. N & Salts

• ARE THERE APPROPRIATE MODELS?

– Water, Salts & Nitrogen Management (Saltmed; APSIM; etc.)

Challenges & On-going Challenges & On-going ActivitiesActivities……

INPUTSINPUTSField Trials ResultsoSoil data

Texture; Soil Layers; Saturated Hydraulic Conductivity; Infiltration Rates;

oClimate dataETo & Rainfall

oIrrigation & drainage dataDepths; Timing & EC; Irrigation Water Management

oGroundwater dataDepth & EC

oCrop dataPlanting date; Yield, etc.

HYROLOGICAL MODEL

CROP MODEL

WATER & NUTRIENTS MODEL

INTEGRATED MODELLING

SOUND

ENVIRONMENTAL

SCENARIOS

FARMER’S

PERSPECTIVES

OUTPUTS

Recommendations

Improved Irrigation Water and Nitrogen & Salt Management

Practices

Challenges & On-going Challenges & On-going ActivitiesActivities……

• AGREED ON THE CHAPTERS (THESIS)

• WRITING UP

• HOPEFULLY TO SUBMIT BY THE END DECEMBER 2009

Thank you!