A presentation from the WCCA 2011 conference in Birsbane.

1. Maize Yield Increases and Stabilization
under CA in semi-arid Districts of Tanzania
by
Saidi Mkomwa1; Zakaria Mkoga1;
Wilfred Mariki2 and Marietha Owenya2
1African Conservation Tillage Network (ACT);
2Selian Agricultural Research Institute (SARI)
Presented at
The Fifth World Congress on Conservation Agriculture,
Brisbane Convention & Exhibition Centre, Brisbane Australia
26 – 29 September 2011

2. Contents
1. Introduction
2. Materials and Methods
3. Results and Discussions
4. What are the Implications for smallholder
adoption of CA?
5. Acknowledgements

3. Introduction–study sites &farmers
CA SARD project phase 2 from 2007 to
March 2011.
Funded by German Govt, Implemented
by FAO with the Tanzania and Kenya
Governments
8000 households learned CA by doing

4. CA SARD
PROJECT
Scaling Up CA in Africa

5. Materials and Methods
 Study of 8 FFS from Arumeru & Karatu
Districts, Arusha Region Tanzania
 For three consecutive years from 2005
to 2007.
 Gender mixed farmer groups with 20 –
25 farmers each cultivating about 2ha.
 Learning CA by experimenting with
alternative crop production technologies

6. Treatments
1. Jab planter, glyphosate weed control, lablab
cover crop planted after first weeding,
2. Ripping, glyphosate weed control, jab planting
in the ripper furrow, pigeon peas intercrop,
3. Jab planter, glyphosate weed control, pigeon
peas intercrop,
4. Ripping, glyphosate weed control, jab planter,
lablab cover crop and
5. Farmers practice - ox ploughing, hand hoe
weed control.

7. Oxen ripping
Jab planting Oxen direct seeding

8. Schematic Plot-layout vs Treatments
Plot 1 Plot 2 Plot 3 Plot 4 Plot 5
Jab Ripper Jab Ripper Plough
Reduced; Farmer’s
COVER SEED PLA- TILLAGE
None Reduced; None
AD ripper A/Drawn Practice –
ripper (Plough)
Jab AD direct Jab AD direct Hand hoe
CEMENT
planter seeder planter seeder (for Maize
& Beans)
Lablab Pigeon Pigeon Lablab Traditional
CROP
peas peas (Beans -
crop)

9. Plot 1 Plot 2 Plot 3 Plot 4 Plot 5
Jab Ripper Jab Ripper Plough
Maize All All All All crop
MAINTENAN
CE OF SOIL
stover tops residues residues residues residues
COVER
only retained retained retained removed
removed
Lablab None None Pigeon None
COVER CROP
years 1& 2 Maize Maize peas for Maize /
ROTATIONS
Pigeon only only years 1&2 beans
peas years Lablab for intercrop
3 and 4 years 3&4

10.  Plot sizes varied from one FFS to
another, ranging from 390 - 1440 m2.
 Data collected on: rainfall, labour
input, soil property changes, maize
grain yield and cover crop grain yield.
 Recommended crop spacing and use of
improved maize seeds were practiced.
 Neither industrial nor inorganic
fertilizers were used.

11. Maize Grain Yield (Means for 6 FFS plots)
No Treatment Maize grain yield (kg/ha)
 Each FFS treated as a replication
. 2005 2006 2007
1 Data analysed using by SAS
 Jab planter,
glyphosate, lablab
programme 1,735 2,889 2,738
2 Ripping, glyphosate,
jab, p/peas 1,949 3,018 1,973
3 Jab planter,
glyphosate, p/peas 1,770 2,566 1,369
4 Ripping, glyphosate,
jab, lablab 2,043 2,357 1,320
5 Farmer’s practice, ox
ploughing 1,353 1,502 993
Grand mean 1,770 2,466 1,679
Annual rainfall 528 755 988
(mm) (532)
Source: ARI Selian field data, 2007; Arusha foundation seed farm (some rainfall records).

12. CROP YIELDS DUE TO CA WITH TIME
3,500
3,000
2,500
YIELDS (kg/ha)
2,000
Jab planter, glyphosate,
1,500 lablab
Ripping, glyphosate, jab,
p/peas
Jab planter, glyphosate,
1,000 p/peas
Ripping, glyphosate, jab,
lablab
500 Farmers practice, ox
ploughing
-
2005 2006 2007
YEAR

13. Effect of tillage
 Ripping with either lablab or pigeon peas
produced significantly different and higher grain
yields (of 1,949 & 2,043 kg ha-1 ) vs direct
seeding with the jab planter (1,735 &1,770 kg
ha-1 ) and conventional ox ploughing (1,353 kg
ha-1) during year 1 of CA. 528 mm rainfall
 The trend in yield increase differences continued
during the second year (755 mm)

14.  Jab planter with lablab & p/peas
was highest in year 3 (2,738
kg/ha) followed by ripping
(1,973 with lablab and 1,320 kg
ha-1 with pigeon peas).
 The ox ploughed plots produced
the lowest grain yield
throughout

15. Effect of cover crops.
 The yield increase trends with time
and rainfall variations were
consistent for lablab. It produced
and maintained the highest yield of
2,738 kg ha-1 in year 3 (in a year
with a grand mean of 1,697 kg ha-1)
while pigeon peas dropped
drastically to 1,320 kg ha-1

16. Yield variations across sites
 Yields across different FFS varied
greatly (from a maximum of 7.6
tons/ha in Rhotia Kati for ripper with
pigeon peas to 0.2 tons/ha for the
farmers’ practice in Getamock), which
was understandable due to the
differing farmer management skills
and the initial degraded status of the
fields.

17. Preferred CA technologies
 Of the 352 households practicing
 66% are women
 64% are FFS members
 36% are non-FFS members enticed by
the benefits of CA;
 The preferred planting/tillage
technologies are:
 the ripper (61%) for FFS members;
complimented by the jab planter for seed
placement, or manual

18. CONCLUSIONS
 CA increases and stabilise yields with
time and with fluctuations in rainfall
compared to conventional ploughing.
 Increases in grain yields increase
food security.
 POINT OF DEPARTURE: Increased
yields for smallholders owning small
pieces of land (typically 1 ha) does
not enable them to eradicate poverty.

19. Conclusions ..
 CA translates to saved time (up to
57% of the growing season) – which
might not necessarily translate into
meaningful utilisation if opportunity
costs are not accessible
 What is 2 months of saved time if
there is nothing productive to do in
the remaining 8 months of the year?

20. THE WAY FORWARD
Make full use of CA based value chains
Walking tractor seeder development
Value addition of oil seeds under CA rotations
Access to equitable markets

21. ACKNOWLEDGEMENTS
CA SARD was funded by the
Government of the Federal Republic
of Germany and implemented by
FAO, The Governments of Tanzania
and Kenya. ACT coordinated the
project at the Regional Level.
Their support is sincerely
acknowledged

22. We have the opportunity to make a difference ….
… we, not somebody else …
www.act-africa.org
THANK YOU