Conservation Agriculture (CA) in Southern Africa: Longer term trends in soil quality and crop productivity

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Conservation Agriculture (CA) in Southern Africa
Longer term trends in soil quality and crop
productivity
By Christian Thierfelder and Isaiah Nyagumbo In
collaboration with Amos Ngwira, Ivy Ligowe,
Sebastiao Famba, Ivan Cuvaca, Mwangala Sitali,
Tobias Charakupa, Herbert Chipara and Sign Phiri
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Introduction
Environmental situation in southern Africa

• Unreliable climatic conditions (drought)
• Challenging soils
• Increased physical, chemical and biological soil
  degradation
• Reliance on maize as staple food crop

A possible solution

• Sustainable crop intensification through
  Conservation Agriculture (CA) .

. BUT widespread promotion of CA in southern
Africa without scientific base has also provoked
a lot of critique!
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Trial Locations in Southern Africa

• Henderson Research Station, Zimbabwe (since
  2004/05), 884 mm average rainfall
• Farmers Training Center, Monze, Zambia (since
  2005/06), 748 mm average rainfall
• Sussundenga Research Station, Chimoio, Mozambique
  (since 2006/07), 1155 mm average rainfall
• Chitedze Research Station, Lilongwe, Malawi
  (since 2007/08), 920 mm average rainfall

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Treatments to focus on
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• AT Direct seeder

• Fitarelli jab-planter

• Dibble stick

• Magoye ripper

• Basin planting

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Results from the LT trials
Three phases of a crop rotation
(Maize-Cotton-Sunnhemp) in Monze, Zambia
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Infiltration
Henderson
Monze
Chitedze
Sussundenga
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Cumulative soil erosion from 2005-2011
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Soil moisture in 0-60cm, Henderson, Zimbabwe,
2009/2010
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Soil moisture in 0-60cm, Monze, Zambia, 2009/2010
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Effect of treatments on soil organic carbon in
the CA LT trial in Monze FTC. 0-30 cm, Zambia,
October 2005 and 2008.
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Aggregate stability () at Monze FTC, 2009
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Summary of maize grain yield at Henderson,
Zimbabwe, 2005-2011
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Summary of maize grain yield at Monze FTC,
Zambia, 2006-2011
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Summary of maize grain yield at Sussundenga,
Mozambique, 2007-2011
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Summary of maize grain yield at Chitedze, Malawi,
2007-2011
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Conclusions

• CA offers many opportunities for farmers in
  southern Africa
• Results from LT trials show
• higher infiltration,
• lower soil erosion,
• higher soil moisture,
• Increased carbon and aggregate stability
• Higher crop performance in the longer term
• Benefits of CA emerge over time
• Rotations play a significant role in CA cropping
  systems

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Conclusions

• Promoting CA in southern Africa has challenges
• Residue retention
• Rotations
• Weed control
• Mindset

• More socio-economic and biophysical studies are
  needed to understand and overcome those
  challenges
• The CA trials are the only source of scientific
  longer term data in southern Africa..
• ..they need to be supported (financially) and
  used effectively (by science)...!

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Thank you very much for your attention!
CA long-term trial at the Monze Farmer Training
Centre, Zambia