A presentation from the WCCA 2011 event held in Brisbane, Australia.

1. The effect of tillage practice and residue management
on wheat yield and yield stability in two agro-
ecological environments in Mexico

2. Two cropping systems
Cd. Obregón (39 m):
Irrigated wheat-based system
El Batán (2249 m)
Mexico
Rainfed highland system
City

3. Strategic research
● Long-term and component technology trials
● Different environments
Contrasts and similarities => process level
Keeps thinking flexible
Obregon => mimic environments
● Network of excellence
● Center of training => on farm trials

7. El Batán: Characteristics
● Non-equatorial semi-arid highlands (2240 masl)
● Rain fed agriculture
● Periodical drought
● Periodical water excess
● Wind and water erosion
● Grain yield < 2 ton ha-1

8. El Batán: Characteristics
● Soil: Haplic Phaeozem
(Clayic)

9. El Batán: target environment

10. Treatments
● Zero tillage
● Conventional tillage
 after harvest
 One pass with a chisel plough to 30 cm depth
 Two passes with a disk harrow to 20 cm depth and two passes
with a spring tooth harrow to 10 cm.
 The spring tooth harrow was used when needed for weed
control (typically twice) during the winter fallow season.
 the seed bed preparation
 One pass with a chisel plough to 30 cm depth
 Two passes with a disk harrow to 20 cm depth and one pass
with a spring tooth harrow to 10 cm

11. Govaerts et al., 2005
Govaerts et al., 2005

12. Govaerts et al., 2005
Govaerts et al., 2005

13. Zero vs. Conventional
ZT CT
Govaerts et al., 2005
Govaerts et al., 2005

14. Total monthly precipitation
(mm) El Batán, México
Average
2008 2009
Month 1991-2007
June 106 102 105
July 116 102 39
August 117 153 63

15. Zero vs. Conventional
ZT CT
Govaerts et al., 2005

16. El Batán: results
8
7
Grain yield (t/ha at 12% H2O)
6
5
4
3
2
1
0
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
Year
ZT-Keep ZT-Remove CT-Keep
CT-Remove ZT-KeepM1/3W ZT-Keep1/2
CT: conventional tillage; ZT: zero tillage

17. El Batán: results
Management Average yield Coefficient of
practice (t ha-1 at 12% H2O) variation (%)
CT-Keep 5.31 BC 22.3 B
CT-Remove 5.04 C 23.2 B
ZT-Keep 5.96 A 19.0 B
ZT-Remove 3.92 D 35.8 A
ZT-Keep M1/3W 4.93 C 33.8 A
ZT-Keep1/2 5.59 AB 24.7 B
CT: conventional tillage; ZT: zero tillage

18. El Batán: results
Management Slope Inter- R²
practice cept
CT-Keep 0.82 1.12 0.85
CT-Remove 0.88 0.52 0.86
ZT-Keep 0.82 1.77 0.80
ZT-Remove 1.06 -1.49 0.86
ZT-Keep M1/3W 1.33 -1.90 0.97
ZT-Keep1/2 1.09 -0.02 0.94
CT: conventional tillage; ZT: zero tillage

19. Cd. Obregón: Characteristics
● Arid coastal plains (39 masl)
● Irrigated agriculture
● Irrigation applied in furrows

20. Cd. Obregón: Characteristics
● Soil: Haplic Vertisol
(Calcaric, Chromic)
15 cm
35 cm
80 cm
110 cm

21. Cd. Obregon: target environment

22. Treatments
● Permanent beds
● Conventional tillage
 after harvest of each crop
 disk harrow to 0.20 m depth (2–3 passes)
 the seed bed preparation
 Remaking the beds => weed control

23. Cd. Obregón: results
8.0
Grain yield (t/ha at 12% H2O)
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Year
CTB-Keep PB-Burn PB-Remove PB-Partial PB-Keep
CTB: conventionally tilled beds; PB: permanent beds

24. Cd. Obregón: results
Management Average yield Coefficient of
practice (t ha-1 at 12% H2O) variation (%)
CTB-Keep 7.01 BC 10.69 A
PB-Burn 6.65 C 11.66 A
PB-Remove 7.24 AB 9.53 A
PB-Partial 6.91 BC 10.28 A
PB-Keep 7.42 A 8.65 A
CTB: conventionally tilled beds; PB: permanent beds

25. Cd. Obregón: results
8.5
Treatment yield (Mg/ha at 12% H2O)
8.0
Management Slope Inter- R²
7.5
practice cept
7.0 CTB-Keep 1.07 -0.52 0.95
PB-Burn 1.09 -0.98 0.91
6.5
PB-Remove 0.96 0.42 0.96
6.0
PB-Partial 1.00 -0.11 0.93
5.5 PB-Keep 0.85 1.44 0.91
5.0 CTB: conventionally tilled beds; PB: permanent
5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 beds
Year mean yield (Mg/ha at 12% H2O)
CTB-Keep PB-Burn
PB-Remove PB-Partial
PB-Keep Linear (CTB-Keep)
Linear (PB-Burn) Linear (PB-Remove)
Linear (PB-Partial) Linear (PB-Keep)

26. Conclusion
● CA highest yielding in both environments
● Differences in stability were only found in rain
fed, more adverse conditions
● Straw fully removed or burned combined with ZT
is not sustainable
● More research is needed to design optimal
systems with partial residue retention

27. http://conservacion.cimmyt.org
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