1. Benefits and Challenges of Crop Rotations in Maize-based Conservation Agriculture (CA) Cropping Systems of Southern Africa
By Christian Thierfelder and Stephanie Cheesman

2. Outline of this presentation
Introduction
Biophysical benefits of rotations
Economic benefits of rotations and associations
Challenges in promotion of rotations and associations
Priorities for future interventions

3. The focus of this talk: Crop rotations and associations
Minimal soil movement
Surface crop residue retention
Crop rotations and associations

4. Rotations: the most neglected principle of CA
CA principle
% practicing in 2009/10 season
Basin preparation
100
Mulching 51
Rotation 18
24 Districts and wards visited
720 HHs interviewed
CA beneficiaries only
Source FAO, 2010.
CA pre-harvest survey

5. Rotations: the most neglected principle of CA …..contd.
Reasons:
Dedication of limited land area to food security crops
Marketing of rotational crops and economic considerations
Un-availability of seed (GMCCs)
Nature of current CA extension – focus more on relief less on recovery
Planting patterns - row crops in basin systems
Limited information

6. Some benefits of rotations and associations are known for generations……..!
Reduction in pest and diseases
Biological N-fixation through leguminous crops
……others are relatively unknown!

7. Analysis of crop rotations at the Monze Farmer Training Centre, Zambia, 2006-2010
Treatments:
Conventionally ploughed control plot (CPM)
Direct seeded sole maize (DSM)
Direct seeded cotton-maize rotation (DS-CM)
Direct seeded cotton-sunnhemp-maize rotation (DS-CSM)

8. Biophysical benefits of rotations and associations
Effects on water infiltration, Monze, Zambia, 2009

9. Direct seeded: maize
Conventional ploughing
Direct seeded: maize-cotton
Direct seeded: maize-cotton-sunnhemp

10. Biophysical benefits of rotations and associations
Effects on available soil moisture, Monze, Zambia

11. Biophysical benefits of rotations and associations
Effects on soil carbon in the first 10 and 30 cm,
Monze, Zambia
Treatments
Total Ca
rbon (%)
Change cm
2008
0-10cm %
2005
0-30cm
Conventional ploughing
0.67
0.56 b
-16.4
0.58
0.54 c
-7.3
DS: maize
0.72
0.76 a
+5.6
0.69
0.75 a
+9.4
DS: cotton-maize
0.64
0.68 ab
+6.3
0.61
0.61 bc
+0.6
DS: cotton-sunnhemp-maize
0.68
0.77 ab
+13.2
0.63
+8.3

12. Biophysical benefits of rotations and associations
Effects on aggregate stability, Monze, Zambia

13. Biophysical benefits of rotations and associations
Earthworms counts, Monze, Zambia

14. Biophysical benefits of rotations and associations
Effects on maize yield, Monze, Zambia

15. Economic benefits of rotations and associations
Maize-cotton rotation, Monze, Zambia, 2009

16. Overall Gross Margin (US$ ha-1 year-1), Monze Farmer Training Centre, Zambia [without market for sunnhemp and low market for cotton]

17. Overall Gross Margin (US$ ha-1 year-1), Monze Farmer Training Centre, Zambia [with market for sunnhemp]

18. Economic analysis, Malawi, Total Land Care, 2009
Assumptions:
Analysis based on 12 TLC/CIMMYT demonstration plots
Control: planted in ridge and furrow system
CA planted on the flat with dibble stick
Legume: Pigeon pea intercrop
Herbicide use on CA plots

19. Why are farmers not adopting rotations?
Malawi:
Over 70% of cropped land is dedicated to maize
Farmer own less than 1 ha land on average
Food security considerations more important than income generation
Possible solutions:
maize-pigeon pea intercropping
maize-cowpea intercropping
Maize-pigeon pea intercropping

20. Why are farmers not adopting?…contd.
Zambia:
Farmer own more land (optimal utilization)
Farmers experiment with some cash crops in rotations (cowpea, cotton, groundnuts) but
Markets are often not available to sell surplus
Unavailability of seed (GMCCs)
Possible solutions:
Concentration and increased productivity of maize
Rotations and GMCCs on remaining land
Development of functional markets
Maize-cowpea rotation under CA

21. Priorities for future CA promotion
Farm level:
Encourage rotations and associations wherever possible
Promote growing important cash crops (i.e. groundnuts, cassava, tobacco, cotton etc.) under CA
Develop technical bulletins for various rotational crops under CA
Identify niches for different rotational crops in the farming systems
Growing paprika under CA

22. Priorities for future CA promotion
Policy level:
Create an enabling environment for input and out markets to facilitate selling of produce
Promote CA not as a “maize only system” but as a whole farming system
Support research on rotations and associations for sustainable crop production
Rotations with different green manure cover crops in CA

23. THANK YOU FOR YOUR ATTENTION!