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Adaptive capacity of maize-based conservation agriculture to climate stress in Malawi

  1. Adaptive capacity of maize-based conservation agriculture to climate stress in Malawi Amos Ngwira Peter Steward Christian Thierfelder Rothamsted Research Centre, 23 May 2018
  2. Challenges
  3. Yield gaps in southern Africa are between 50% to more than 100%!
  4. Average Maize Grain Yields - Malawi Time (years) 1980 1985 1990 1995 2000 2005 2010 2015 2020 Averagemaizeyields(Mgha-1) 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 Source: MoAIWD, 2015
  5. Projected change in agriculture productivity, 2080 Source: Hugo Ahlenius, UNEP/GRID-Arendal.
  6. Conservation agriculture CA comprises the following principles: • Minimal soil movement • Surface crop residue retention • Crop rotations and/or associations
  7. Reasons for on-station longer-term trials… • To get a scientific understanding of specific CA systems • To quantify the longer-term effects on chemical, physical and biological soil quality and water dynamics • To calibrate and validate crop/soil simulation models • To assess the potential effects and consequences of widespread adoption of CA to be able to convince policy makers
  8. Long term experiments in southern Africa • Henderson Research Station, Zimbabwe (since 2004/05) • Farmers Training Center, Monze, Zambia (since 2005/06) • Susundenga Research Station, near Chimoio, Mozambique (since 2006/07) • Chitedze Research Station, Lilongwe, Malawi (since 2007/08) • Domboshawa Training Centre, Zimbabwe ( since 2009/10) • New LT trials under SIMLESA and SIMLEZA (Msekera Research Station)
  9. Treatments • Check plot (CP); traditional farmers practice using hand hoe (ridge and furrow system), maize as a sole crop, no residue retention, stubble removed for the following season • Basin (BA); maize as a sole crop, residues retained • Dibble stick (DS); maize as a sole crop, residues retained • Crop rotation (A); direct seeding with dibble stick, maize- cowpea rotation, residues retained • Crop rotation (A2); direct seeding with dibble stick, cowpea- maize rotation, residues retained • Maize intercropping (IP); direct seeding with dibble stick, maize with pigeon pea intercropping, residues retained • Maize intercropping (IC); direct seeding with dibble stick, maize with cowpea intercropping, residues retained • Maize intercropping (IM); direct seeding with dibble stick, maize with velvet bean intercropping (seeded 8 weeks after maize), residues retained
  10. How does CA enhance adaptive capacity of maize-based systems to climate stress? Conventional ridge tillage Conservation agriculture
  11. Remarkable increase in infiltration in CA systems compared with conventional tillage Time (min) 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Infiltrationinmmh-1 0 10 20 30 40 50 60 70 80 90 100 110 120 130 Conventional ploughing - Maize CA- Dibble stick, Maize CA- Dibble stick, Maize-Cowpea
  12. CA performance in a wet and dry year, Malawi, 2007/08 and 2011/12 Maizegrainyield(kgha-1 ) 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 4018 4948 4789 Conventional ridge tillage CA + sole maize CA + maize/legume intercropping Wet year 2007/2008 2485 4086 4223 Dry year 2011/12
  13. Predicted crop yields, 2010-2030 13 Years 2010 2015 2020 2025 2030 Maizegrainyield(kgha -1 ) 2000 3000 4000 5000 Growingseasonrainfall(mm) 0 200 400 600 800 1000 1200 1400 1600 1800 year vs CT-sole maize year vs CA-sole maize year vs CA maize-cowpea rotation rain
  14. Selection of management options through strategic and economic analysis Cumulative probability distribution plots on maize yields Stochastic dominance analysis of monetary returns ($/ha)
  15. Simulating drought, Chitedze 2015-2017
  16. Effect of drought on flowering dates, Chitedze 2015-2017 P = planting U = erection of shields D = removal of shields * = Flowering date CA = flowering date CP Steward et al 2018 in prep
  17. AB AC AB CD DE AB ADG EF CEGH ABDH DEF A A B BC BC BC BC C Maize grain yields simulating drought Steward et al 2018 in prep
  18. Conclusion • CA resulted in enhanced capacity of maize-based cropping systems to drought stress in Malawi • However in wet seasons there is no clear yield advantage of CA versus conventional tillage • In drier years, CA resulted in higher soil water infiltration that resulted in improved soil water content in CA compared with conventional tillage • For wider adoption, CA needs to be tailored to local biophysical and climate context as well as by targeting where farmers might manage cover
  19. Role of mechanization and labour saving technologies
  20. ACKNOWLEDGEMENT
  21. Thank You
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