INVESTIGATING CONSERVATION INVESTIGATING CONSERVATION AGRICULTURE SYSTEMS IN ZAMBIA AND AGRICULTURE SYSTEMS IN ZAMBIA AND
ZIMBABWE TO MITIGATE FUTURE ZIMBABWE TO MITIGATE FUTURE EFFECTS OF CLIMATE CHANGEEFFECTS OF CLIMATE CHANGE
By Christian Thierfelder and Patrick C. WallBy Christian Thierfelder and Patrick C. Wall
Table of content IntroductionIntroduction
Brief description of trial sitesBrief description of trial sites
Effects of CA on infiltration Effects of CA on infiltration and soil moistureand soil moisture
Yield responses to soil Yield responses to soil moisturemoisture
ConclusionsConclusions
Introduction:Introduction:Most models suggest that the southern African region will be Most models suggest that the southern African region will be affected by climate changeaffected by climate change
IPCC, AR4, 2007IPCC, AR4, 2007
Effect of climate change on crops in Effect of climate change on crops in southern Africasouthern Africa
The big losers in The big losers in southern Africa in southern Africa in terms of production terms of production will be maize and will be maize and wheatwheat
(Lobell et al., 2008. Science)
Farmer need to adapt to the new situation!
Change in management (date of planting)Change in management (date of planting)
Change in variety e.g. to shorter (or longer?) Change in variety e.g. to shorter (or longer?) season varietiesseason varieties
Change in fertiliser use (targeting and Change in fertiliser use (targeting and concentrating fertilizers)concentrating fertilizers)
Change in crops - e.g. to more drought resistance Change in crops - e.g. to more drought resistance speciesspecies
Change towards Change towards water-efficient cropping systemswater-efficient cropping systems
Water efficient cropping systemsWater efficient cropping systems::
Retain more water on-site through:Retain more water on-site through:
Higher infiltrationHigher infiltration
Less water run-offLess water run-off
Reduced evaporationReduced evaporation
Higher water storage in Higher water storage in the soil the soil
Higher biological activity Higher biological activity (earthworms create soil (earthworms create soil pores)pores)
The more water can be retained and stored on-The more water can be retained and stored on-site the more there is available for crop site the more there is available for crop
production!production!
Effects of CA on Earthworm counts, Effects of CA on Earthworm counts, Monze, FTC, Zambia 2007Monze, FTC, Zambia 2007
What is Conservation Agriculture?What is Conservation Agriculture? CA comprises the following
principles:
– Minimal soil movement
– Surface crop residue retention
– Crop rotations and green manure cover crops
LocationsLocations
Henderson Research Station (HRS), Mashonaland Central Province, Zimbabwe17.57°S, 30.99°E, 1136 m.a.s.l
Monze, Farmers Training Center (MFTC), Zambia16.24°S, 27.44°E, 1103 m.a.s.l
Brief description of treatmentsBrief description of treatments
Conventional ploughing, maize, no residues
CA: direct seeding, maize, residue retention
CA: direct seeded rotation, maize after cotton, residues retention
Conventional ploughing, maize, no residues
CA: direct seeding, maize, residue retention
CA: rip-line seeding, maize, residue retention
Henderson Research Station, Zimbabwe (HRS)Henderson Research Station, Zimbabwe (HRS)
Monze, Farmer Training Centre, Zambia (MFTC)Monze, Farmer Training Centre, Zambia (MFTC)
Infiltration curves measured by mini-rainfall simulator in January 2008 (left) and 2009 (right) in two conservation agriculture and one conventional treatment, Henderson Research Station, Zimbabwe
January 2008January 2008 January 2009January 2009
Infiltration curves measured by mini-rainfall simulator in January 2008 (left) and 2009 (right) in two conservation agriculture and one conventional treatment, Monze, Farmer Training Centre, Zambia
January 2008January 2008 January 2009January 2009
Crops are at tasselingCrops are at tasseling
Available soil moisture in the first 60cm at the Monze Available soil moisture in the first 60cm at the Monze Farmer Training Centre, Zambia, 2005/2006Farmer Training Centre, Zambia, 2005/2006
Crops are at tasselingCrops are at tasselingCrops are at tasselingCrops are at tasseling
Soil moistureSoil moisture
measurements,measurements,
Monze, FTC,Monze, FTC,
2008/20092008/2009
Initial crop Initial crop developmentdevelopment
Available soil moisture in the first 60cm at the, Monze Available soil moisture in the first 60cm at the, Monze Farmer Training Centre, Zambia, 2008/2009Farmer Training Centre, Zambia, 2008/2009
Initial crop Initial crop developmentdevelopmentInitial crop Initial crop developmentdevelopmentInitial crop Initial crop developmentdevelopment
Maize grain yield in four consecutive years at Monze Maize grain yield in four consecutive years at Monze Farmer training Centre, 2005-2009Farmer training Centre, 2005-2009
Maize grain yield in five consecutive years at Maize grain yield in five consecutive years at Henderson Research Station, Zimbabwe, 2004-2009Henderson Research Station, Zimbabwe, 2004-2009
Conclusions: CA has the potential to improve the soil water balance CA has the potential to improve the soil water balance
of major cropping systems in southern Africa and of major cropping systems in southern Africa and mitigate seasonal dry spellsmitigate seasonal dry spells
At HRS, Zimbabwe and MFTC, Zambia a generally At HRS, Zimbabwe and MFTC, Zambia a generally higher infiltration and soil moisture content was higher infiltration and soil moisture content was discovered on CA plotsdiscovered on CA plots
Conclusions: contd...... However, in some cases, higher soil moisture did not However, in some cases, higher soil moisture did not
transform into higher maize yieldstransform into higher maize yields
Higher available soil moisture will reduce the risk of Higher available soil moisture will reduce the risk of crop failure and therefore contribute to improved crop failure and therefore contribute to improved livelihood of African smallholder farmers.livelihood of African smallholder farmers.
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