How "Climate-Smart" is Conservation Agriculture in Southern Africa?
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How “Climate-smart” is Conservation Agriculture in Southern Africa? By: Christian Thierfelder
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Transcript of How "Climate-Smart" is Conservation Agriculture in Southern Africa?
How “Climate-smart” is Conservation Agriculture in Southern Africa?
By: Christian Thierfelder
The Challenges:
Days after planting in each cropping season
0 20 40 60 80 100 120 140 160 180 200 220
Cum
mul
ativ
e ra
infa
l (m
m d
-1)
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50
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2004/2005
2006/2007
2012/2013
2011/2012
2008/2009
2010/2011
2009/2010
2005/2006
2007/2008
Uncertenties increase!Rainfall variability in Zimuto Communal Area, Zimbabwe 2004-2013
Thierfelder et al., 2014
Yield gaps in southern Africa are between 50% to more than 100%!
Time (years)
Ave
rag
e m
aiz
e y
ield
kg
ha-1
0
500
1000
1500
2000
2500
3000
Average maize yield in Zimbabwe
Average Maize Grain Yields - Zimbabwe
Source: FAOSTAT, 2014
Projected change in agriculture productivity, 2080
Source: Hugo Ahlenius, UNEP/GRID-Arendal.
Sust
aina
ble
incr
ease
in
prod
uctiv
ityC
limate change
adaptation
Climate change mitigation
Climate-smart Agriculture (CSA)
CSA
How is Conservation Agriculture being defined?CA comprises the following
principles: • Minimal soil movement• Surface crop residue retention• Crop rotations and green manure
cover crops
Why Conservation Agriculture? To combat increasing land
degradation (physical, biological and chemical)
To respond to climate variability and change….
The need for more efficient use of resources (sustainable intensification)
Rising production costs To reduce the risk of crop failure
Known challenges of CA system... Biomass trade-offs in mixed crop livestock systems-
competition for residues
The Malawi “Sausage”
Known challenges of CA system... Weed control in the initial years CA needs changes in the way farmers do agriculture Availability of critical inputs (equipment, herbicides) Farm size – sometimes limits rotation Yield benefit delayed in some systems Moisture limits adoptability
• Basin planting
• Jab-planter • AT Direct seeder
• Dibble stick
• Hoe-planter
• Magoye ripper
New mechanization ideas....?
How does CA adress the three different pillars: adaptation, mitigation and productivity.....?
Climate Change Adaptation
Conventional ridge tillage Conservation agriculture
Earthworm counts in the first 30 cm, Monze, 2010/2011
d
a
abcd
abc
abcd
bcd
ab
a
bcd
cd
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
CP- Maize DS- Maize BA- Maize DS- Cotton/Maize
DS- Maize/Cotton
DS-Sunnhemp/
Maize/ Cotton
DS- Maize/Cotton/
Sunnhemp
DS- Cotton/Sunnhemp/
Maize
CP- Cotton/Maize
CP- Maize/Cotton
Treatments
Ear
thw
orm
co
un
ts (
cou
nts
/m²)
Conservation agriculture treatments
Time (min)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n in
mm
h-1
0
10
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130
Conventional ploughing - MaizeCA- Dibble stick, MaizeCA- Dibble stick, Maize-Cowpea
Chitedze, Malawi
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, maizeRip-line seeded, maize
Direct seeding, maizeRip-line seeded, maize-cowpea
Henderson, Zimbabwe
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
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70
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90
100
110
120
130
CA- Direct seeding, maize
Conventional ploughing, maize
CA- Direct seeding, maize after sunflower
Sussundenga, Mozambique
Time (min)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Infi
ltra
tio
n r
ate
(in
mm
h-1
)
0
10
20
30
40
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90
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130
Direct seeding, maize-cotton
Conventional ploughing, maize
Direct seeding, maize-cotton-sunnhemp
Direct seeding, maize
Monze, Zambia
Infiltration is crucial in CA systems!
Soil moisture, 0-60cm, MFTC, 2011/2012
Date
Ra
in
fa
ll (m
m d
-1 )
0
10
20
30
40
50
60
70
80
Ava
ila
ble
s
oil m
ois
tu
re
(m
m)
0
20
40
60
80
100
120
140
160
180
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240
Conventional ploughing, maize (CP-M)
Direct seeding, maize (DS-M)Direct seeding, maize-cotton (DS-MC)
Rainfall 2011/2012
Yield gain DSM: 27% DSMC: 53%
CA performance under seasonal dry spells, Monze Farmer Training Centre
Date
Ra
infa
ll (
mm
d-1
)
0
10
20
30
40
50
60
70
80
Ava
ila
ble
so
il m
ois
ture
(m
m)
0
10
20
30
40
50
60
70
80
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120
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140
150
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field capacity
50% avail. moist.
Rainfall in 2005/2006, total 734 mmBasin planting (BA)
Conventional ploughing (CP)Direct seeding (DS)
Source: Thierfelder and Wall, 2010
CA performance in a wet and dry year, Malawi, 2007/08 and 2011/12
Ma
ize
gra
in y
ield
(kg
ha
-1 )
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
4018
4948 4789
Conventional ridge tillageCA + sole maizeCA + maize/legume intercropping
Wet year 2007/2008
2485
40864223
Dry year 2011/12
+23% +19%
+64% +70%
Too much water…… Balaka 2015!
Ma
ize
gra
in y
ield
(kg h
a-1 )
0
1000
2000
3000
4000
5000
6000
ihi
bcde
cdef
bcdabc ab
a
def
Conventional tillage CA-Basin planting CA-Direct seeding
cdefcdefcdef
ghi
efg efgdefg
fghefg defg
def def
Traditional variety, Matuba DT variety, ZM309
DT variety, ZM401
DT variety, ZM523
DT variety, ZM625
DT variety, Pan53
DT variety, Pristine601
Adaptation to Climate Change – Integration of Climate-smart Technologies
Climate Change Mitigation!
What do we know about the mitigation potential of CA? Improved mitigation potential through more
efficient water and nutrient use (precision agriculture, microdosing)
Reduced fossil fuel needs for land preparation Small reductions (CO2) but also increased (NOx) in
GHG emissions Overstatement of the global potential for soil C
sequestration under no-till agriculture (Powlson et al. 2014)
Mitigation potential ● Data on soil carbon
sequestration inconclusive – some studies report benefits, some not…..! (Govaerts et al. 2009, Ngwira et al. 2012; Thierfelder and Wall 2012)
● Carbon accumulation depends on organic inputs and is often observed in the first 0-30 cm but not in deeper layers
Soil carbon dynamics, Monze FTC, 2005-2010
0-30 cm
Year
2004 2005 2006 2007 2008 2009 2010 20110
5
10
15
20
25
30
35
Conventional agriculture, maizeCA, maizeCA, maize-cotton rotationCA, maize-cotton-sunnhemp rotation
Sustainable Increase in Maize Productivity
Longer term maize grain yields on farmers fields in Zambia – Monze, 2006-2014Longer term maize grain yields on farmers fields in Zambia – Monze, 2006-2014
Harvest year
2006 2007 2008 2009 2010 2011 2012 2013 2014
Ma
ize
gra
in y
ield
(kg
ha-1
)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Conventional ploughing, maize (CPM)Ripline seeding, maize (RIM)
Direct seeding, maize (DSM)
a
NS
b
b
NS
NS
aa
aa
ab
b
b
a
a
a
b
a
a
b
a
Thierfelder et al. 2013
Regional perspective – Southern Africa, 80% positive maize yield responses to CARegional perspective – Southern Africa, 80% positive maize yield responses to CA
Conventional tillage yield (kg ha-1)
0 2000 4000 6000 8000 10000
Co
ns
erva
tio
n a
gri
cult
ure
tre
atm
ent
yie
ld (
kg h
a-1
)
0
2000
4000
6000
8000
10000
1 :2
line
1:1
line
Planting basins, Mozambique
Ripline seeding, Zambia
Manual direct seeding, Mozambique
Direct seeding, Zambia
Manual direct seeding, Malawi
Manual direct seeding, intercrop., Malawi
Ripline seeding, ZimbabweDirect seeding Zimbabwe
Thierfelder et al. 2015
Overall performance of CA systems in Malawi (a) and Zambia/Zimbabwe (b)
Maiz
e g
rain
yie
ld (k
g h
a-1
)
0
2000
4000
6000
8000
10000
12000
Conventional ridge and furrow system,
sole maize
Conservation agriculture, sole maize
Conservation agriculture, maize/legume intercropping
3555 b 4707 a 4727 aa)
0
2000
4000
6000
8000
10000
12000
Conventional control Ripline seeding AT direct seeding
2760 b 3218 a 3521ab)
Mai
ze g
rain
yie
ld (
kg h
a-1
)
Thierfelder et al. 2015
Years under CA
0 1 2 3 4 5 6 7 8 9 10
-2000
-1000
0
1000
2000
3000
4000
Conventional tillage against rippingF(x)=180.7x - 247.8;
Conventional tillage against direct seedingF(x) = 31.5x + 185.0
b)
Mai
ze y
ield
ben
efit
CP
aga
inst
CA
(kg
ha
-1)
Years under CA
0 1 2 3 4 5 6 7 8 9
Mai
ze y
ield
ben
efit
C
P a
gain
st C
A (
kg h
a-1)
-2000
-1000
0
1000
2000
3000
4000
Conventional against CA, sole maizeF(x)= 54.3x + 1019.7
Conventional agains CA, maize/legumeF(x)= 100.6x + 855.9
a)
Thierfelder et al. 2015
CA performance depending on years of experience in Malawi (a) and
Zambia/Zimbabwe (b)
Economic viability of CA systems in Malawi● CA systems in Malawi are more profitable● Less labour needed for land preparation and weeding● Increased cost for herbicides are easily compensated● Advantages in groundnut systems
Gross margins (USD) maize, Central Malawi
Harvest year
2012 2013 2014
Gro
ss
ma
rgin
s (
US
D)
ma
ize
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Conventional ridge tillage, maize
Conservation agriculture, maize
Conservation agriculture maize/cowpea intercropping
Gross margin (USD), groundnuts, Central Malawi
Harvest year
2012 2013 2014
Gro
ss
ma
rgin
s (
US
D)
gro
un
dn
uts
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Conservation agriculture, groundnuts 1
Conservation agriculture, groundnuts 2
Conventional practice, groundnuts
With CA - 25 labour days saved!
Adaptation potential of CA is high CA improves infiltration and soil moisture CA conserves moisture if residues are applied Mitigation potential inconclusive! Soil carbon increase depend more on organic input than tillage Productivity increase documented after 3-5 cropping seasons CA is more profitable in some areas depending on cropping
systems and inputs used
Thank you very much!
Thank you very much!
