CA and rainfall variability in Zambia: Is CA a promising option for responding to droughts and floods? Bridget Umar

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A presentation made at the WCCA 2011 event in Brisbane, Australia.

A presentation made at the WCCA 2011 event in Brisbane, Australia.

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  • Higher labour requirements for Basins, higherweedinfestationafterfloods

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  • 1. CONSERVATION AGRICULTURE AND RAINFALL VARIABILITY IN ZAMBIA: Is CA a promising option for responding to droughts and floods? Bridget Bwalya Umar and Progress. H.Nyanga
  • 2. NORWEGIAN UNIVERSITY OF LIFE SCIENCES DETTE ER TITTELEN PÅ PRESENTASJONEN Introduction  Smallholder farmers in Southern Africa confronted by risks related to climate, mostly rainfall  Dependence on rain fed agriculture related to low agricultural productivity and variability in production due to water stress during critical crop development stages.  Approaches for dealing with climatic risks include water harvesting.  Conservation Agriculture (CA) promoted partly for its water soil and water loss reduction benefits (Mazvimavi & Twomlow 2009)  In-situ water harvesting effect is the main benefit of CA basins (Enfor et al 2011). www.umb.no 2
  • 3. 3 CA Basins www.umb.noDETTE ER TITTELEN PÅ PRESENTASJONENNORWEGIAN UNIVERSITY OF LIFE SCIENCES
  • 4. NORWEGIAN UNIVERSITY OF LIFE SCIENCES DETTE ER TITTELEN PÅ PRESENTASJONEN CA Basins and Rainfall  Improved water harvesting and water use efficiency in low rainfall areas  Problems of water logging in high rainfall areas.  Basin variant of CA mostly promoted in low rainfall areas.  However, with increasing rainfall variability, probability for low rainfall areas receiving high amounts of rainfall in a given season increasing.  What happens then?  We report on this www.umb.no 4
  • 5. 5 Our study www.umb.noDETTE ER TITTELEN PÅ PRESENTASJONENNORWEGIAN UNIVERSITY OF LIFE SCIENCES
  • 6. NORWEGIAN UNIVERSITY OF LIFE SCIENCES DETTE ER TITTELEN PÅ PRESENTASJONEN Our study  Panel study from 2007 to 2010  640-440 households  interviews with farmers and key informants  Field observations  Focus group discussions, on experiences during drought and flood periods.  Yields from fields under CA and Conventional Agriculture systems compared.  Rainfall data for the study areas for the period. www.umb.no 6
  • 7. NORWEGIAN UNIVERSITY OF LIFE SCIENCES DETTE ER TITTELEN PÅ PRESENTASJONEN Results Farming Season 2006/2007 2007/2008 2008/2009 Average area under CA (ha) 0.22 0.42 0.42 % of cultivated area under CA 11.5 16.5 24.9 Average are under CV (ha) 1.69 2.12 1.27 Total cultivated area (ha) 1.91 2.54 1.69 Average maize yield (tons/ha) 3.39 0.77 1.65 Average rainfall (mm) 1046.3a 1086.8a 858.6b CV = Conventional agriculture. This includes the use of mould board plough and traditional hand hoe for tillage. aMeans followed by the same letter in row are not statistically different at p≤ 0.05 probability level www.umb.no 7
  • 8. NORWEGIAN UNIVERSITY OF LIFE SCIENCES DETTE ER TITTELEN PÅ PRESENTASJONEN Results  % of cultivated area under CA increased steadily over the period.  Flooding experienced during the 2006/2007 and 2007/2008 seasons in the low rainfall study areas.  Large difference in the average maize yields between 2006/2007 and 2007/2008 seasons (importance of rainfall distribution)  Flooding during 2007/8 resulted in lower yields (p=0.0003) www.umb.no 8
  • 9. NORWEGIAN UNIVERSITY OF LIFE SCIENCES DETTE ER TITTELEN PÅ PRESENTASJONEN Discussion  Water logged basins were back-filled , raised to make small ridges. (soil disturbance increased)  FGD reported ability to harvest ”something” from CA fields despite the floods compared to conventionally tilled fields.  Similar sentiments expressed for drought periods.  Continued increase in area under ripping demonstrate farmers’ confidence in the tillage system under flood conditions.  Benefits of early land preparation and early planting associated with CA increases chances of survival of maize, and other crops. www.umb.no 9
  • 10. NORWEGIAN UNIVERSITY OF LIFE SCIENCES DETTE ER TITTELEN PÅ PRESENTASJONEN Area under CA Tillage System 0.35 0.30 0.25 0.20 Area (ha) Basins 0.15 Ripping 0.10 0.05 0.00 2006/2007 2007/2008 2008/2009 Farming season www.umb.no 10
  • 11. NORWEGIAN UNIVERSITY OF LIFE SCIENCES DETTE ER TITTELEN PÅ PRESENTASJONEN Conclusions  CA farmers adapting to climatic variability  Diversifying CA tillage systems to suit the climatic variability.  CA systems being perceived to be more robust in instances of extreme climatic events  Potential for higher production under CA during incidences of both droughts and floods. www.umb.no 11
  • 12. 12 www.umb.no Thank You!DETTE ER TITTELEN PÅ PRESENTASJONENNORWEGIAN UNIVERSITY OF LIFE SCIENCES