conservation agriculture (ca) in southern africa: longer term trends in soil quality and crop...
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Presentation at WCCA5 by Christian Thierfelder and Isaiah NyagumboTRANSCRIPT
Conservation agriculture (CA) in Conservation agriculture (CA) in southern Africa: Longer term southern Africa: Longer term trends in soil quality and crop trends in soil quality and crop productivityproductivity
Conservation agriculture (CA) in Conservation agriculture (CA) in southern Africa: Longer term southern Africa: Longer term trends in soil quality and crop trends in soil quality and crop productivityproductivity
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
IntroductionIntroductionIntroductionIntroduction
Unreliable climatic conditions (drought) Challenging soils Increased physical, chemical and
biological soil degradation Reliance on maize as staple food crop
Environmental situation in southern Africa:
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!
Trial Locations in Southern Africa:Trial Locations in Southern Africa:Trial Locations in Southern Africa: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
Treatments to focus on:Treatments to focus on:Treatments to focus on:Treatments to focus on:
Trial sites Treatments Crops Henderson, Zimbabwe Conventional ploughed control Maize CA- Ripline seeding (Magoye ripper) Maize CA- Direct seeding (Jabplanter) Maize CA- Direct seeding (Jabplanter) Maize-Sunnhemp Monze, Zambia Conventional ploughed control Maize CA- Direct seeding (AT direct seeder) Maize CA- Direct seeding (AT direct seeder) Maize-Cotton CA- Direct seeding (AT direct seeder) Maize-Cotton-Sunnhemp Sussundenga, Mozambique Conventional ploughed control Maize CA- Direct seeding (AT direct seeder) Maize CA- Direct seeding (AT direct seeder) Maize-Sunflower Chitedze, Malawi Conventional ploughed control Maize CA- Direct seeding (Dibble Stick) Maize CA- Direct seeding (Dibble Stick) Maize-Cowpea
•Magoye ripper
•Basin planting
•Fitarelli jab-planter
•AT Direct seeder
•Dibble stick
Results from the LT trialsResults from the LT trialsResults from the LT trialsResults from the LT trials
Three phases of a crop rotation
(Maize-Cotton-Sunnhemp) in Monze, Zambia
Time (min
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n (
mm
h-1
)
0
10
20
30
40
50
60
70
80
90
100
110
120
130
CA- Direct seeding, maizeConventional ploughing, maize
CA- Direct seeding, maize after sunflower
Sussundenga
Time (min)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n (
mm
h-1
)
0
10
20
30
40
50
60
70
80
90
100
110
120
130
CA-Direct seeding, maize-cotton Conventional ploughing, maize
CA-Direct seeding, maize-cotton-sunnhemp CA-Direct seeding, maize
Monze
Time (min)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n (
mm
h-1
)
0
10
20
30
40
50
60
70
80
90
100
110
120
130
Conventional ploughing - MaizeCA- Dibble stick, MaizeCA- Dibble stick, Maize-Cowpea
Time (min)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n (
mm
h-1
)
0
10
20
30
40
50
60
70
80
90
100
110
120
130
Conventional ploughing, maizeCA-Ripline seeding, maizeCA-Direct seeding, maize
Chitedze
InfiltrationInfiltrationInfiltrationInfiltration
Henderson
0
10
20
30
40
50
60
2005/2006 2006/2007 2007/2008 2008/2009 2009/2010 2010/2011
Date
Ero
sio
n in
t/h
a
Conventional ploughing
CA- Direct seeding, maize
CA- Ripline seeding + leg intercrop
Cumulative soil erosion from 2005-2011Cumulative soil erosion from 2005-2011Cumulative soil erosion from 2005-2011Cumulative soil erosion from 2005-2011
Soil moisture in 0-60cm, Henderson, Soil moisture in 0-60cm, Henderson, Zimbabwe, 2009/2010Zimbabwe, 2009/2010
Soil moisture in 0-60cm, Henderson, Soil moisture in 0-60cm, Henderson, Zimbabwe, 2009/2010Zimbabwe, 2009/2010
Soil moisture in 0-60cm, Monze, Zambia, Soil moisture in 0-60cm, Monze, Zambia, 2009/20102009/2010
Soil moisture in 0-60cm, Monze, Zambia, Soil moisture in 0-60cm, Monze, Zambia, 2009/20102009/2010
Effect of treatments on soil organic carbon in Effect of treatments on soil organic carbon in the CA LT trial in Monze FTC. 0-30 cm, the CA LT trial in Monze FTC. 0-30 cm,
Zambia, October 2005 and 2008.Zambia, October 2005 and 2008.
Effect of treatments on soil organic carbon in Effect of treatments on soil organic carbon in the CA LT trial in Monze FTC. 0-30 cm, the CA LT trial in Monze FTC. 0-30 cm,
Zambia, October 2005 and 2008.Zambia, October 2005 and 2008.
ns
ns
ns nsc
a
bc ab
0.00
0.20
0.40
0.60
0.80
1.00
1.20
Conventional control CA - Direct seeding,maize
CA - Direct seeding,cotton-maize
CA - Direct seeding,cotton-sunnhemp-maize
Treatments
To
tal
carb
on
(%
)
2005 2008
decrease: -7.3% increase: +9.4% increase: 0.6% increase: +8.3%
Aggregate stability (%) at Monze FTC, 2009Aggregate stability (%) at Monze FTC, 2009Aggregate stability (%) at Monze FTC, 2009Aggregate stability (%) at Monze FTC, 2009
b
aa
a
0
5
10
15
20
25
30
35
40
45
50
55
Conventionalcontrol
CA - Directseeding, maize
CA - Directseeding, cotton-
maize
CA - Directseeding, cotton-sunnhemp-maize
Treatments
Ag
gre
gat
e st
abil
ity
(%)
Summary of maize grain yield at Henderson, Summary of maize grain yield at Henderson, Zimbabwe, 2005-2011Zimbabwe, 2005-2011
Summary of maize grain yield at Henderson, Summary of maize grain yield at Henderson, Zimbabwe, 2005-2011Zimbabwe, 2005-2011
Harvest year
2005 2006 2007 2008 2009 2010 2011
Mai
ze g
rain
yie
ld (
kg
ha
-1)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Conventional ploughing, maize
CA- Direct seeding, maize
CA- Direct seeding, maize-sunnhemp rotation
b
aa
NS
NS
NS
a
b
c
ab
b
NS
a
Summary of maize grain yield at Monze FTC, Summary of maize grain yield at Monze FTC, Zambia, 2006-2011Zambia, 2006-2011
Summary of maize grain yield at Monze FTC, Summary of maize grain yield at Monze FTC, Zambia, 2006-2011Zambia, 2006-2011
Summary of maize grain yield at Sussundenga, Summary of maize grain yield at Sussundenga, Mozambique, 2007-2011Mozambique, 2007-2011
Summary of maize grain yield at Sussundenga, Summary of maize grain yield at Sussundenga, Mozambique, 2007-2011Mozambique, 2007-2011
Summary of maize grain yield at Chitedze, Summary of maize grain yield at Chitedze, Malawi, 2007-2011Malawi, 2007-2011
Summary of maize grain yield at Chitedze, Summary of maize grain yield at Chitedze, Malawi, 2007-2011Malawi, 2007-2011
ConclusionsConclusionsConclusionsConclusions 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
ConclusionsConclusionsConclusionsConclusions
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)…...!
Promoting CA in southern Africa has challenges: Residue retention Rotations Weed control Mindset
Thank you very much for your Thank you very much for your attention!attention!Thank you very much for your Thank you very much for your attention!attention!
CA long-term trial at the Monze Farmer Training Centre, Zambia