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