Historical Perspectives in Addressing Soil Fertility Problems,Key Soil Fertility Research at IITA

1. Developing ISFM Options for Smallholder
Agriculture in Africa: Experiences from WA
Sylvester OIKEH (Ph D)
Africa Rice Center (WARDA)
Cotonou, Benin
Seminar for the Position of IITA Soil Fertility Specialist
22 September 2008, IITA, Ibadan, Nigeria

2. Outline of Presentation
• Background
• Historical perspectives on soil
fertility
• Key soil fertility research at IITA
• Concept of ISFM
• My vision

3. Outline of Presentation Cont‟d
• Linking vision with key experiences
• Resource mobilization efforts
• Conclusion

4. Background

5. What is Soil Fertility?
• Capacity of the soil to supply
nutrients (N, P, K and other essential
nutrients) to the crop
• Mixture of soil chemical, physical
and biological factors affecting land
potential
• Major problem: Inherent low fertility
of African soils

6. Macronutrient Application Vs. Losses in Africa
5.0 4.4
Million tons per year 4.5 Loss
4.0 Applied
3.5 3.0
3.0
2.5
2.0
1.5
1.0 0.8
0.5
0.5 0.3 0.2
0.0
N P K
Nutrients Source: Sanchez et al. 1997)
• In the developed world, overuse of fertilizer & manure is damaging envt.
• In SSA, low use of fertilizer is a major cause of environmental degradation
and poverty.
• Africa losses USD 4 billion/yr due to soil nutrient mining.

7. SOIL NUTRIENT MINING IS KILLING AFRICA
1995-97 2002-04
Source: IFDC

8. Fertilizer Use Around the Globe
Netherlands Source: FAOSTAT, July 2003;
Vietnam Norman Borlaug, 2004
Japan
UK
China
France
Brazil
USA
India
South Africa
Cuba
Benin
Malawi Fertilizer use: 8 kg per ha
Ethiopia
Mali in Sub-Sahara Africa is the
Burkina Faso
Nigeria
lowest in the world
Tanzania
Mozambique
Guinea
Ghana
Uganda
600 Kg/ha
• Fertilizer Summit, 2006: „to increase the fertilizer use from 8 to 50 kg ha nutrients
0 100 200 300 400 500
-1
by 2015‟.
• Fertilizer is a “golden bullet” to power African Green Revolution (Adesina, 2007)

9. Historical Perspectives in
Addressing Soil Fertility Problems
Period Paradigm Role of fertilizer Role of organic Experiences
inputs
1960s External Use of fertilizer Organic resources Limited success
& input alone will ↑ and played a minor role because of Shortfall
1970s Paradigm sustain yields in infrastructure,
policy, etc.
1980s Organic Fertilizer played a Organic resources Limited adoption; OM
input minimal role are main source of production requires
Paradigm nutrients (Alley excessive land &
farming system) labor
1990s Sanchez’ Fertilizer use was Organic resources Difficulties to access
2nd essential to were the entry organic resources
Paradigm eliminate the main point; but served hampered adoption
nutrient functions beside (e.g. improved fallow)
constraints nutrients release
2000s ISFM Fertilizer is a Access to organic On-going!
Paradigm major entry point resources has both (Here we are!)
to ↑ yields and social and
supply needed economic
Annon (2007) org. inputs dimensions

10. Key Soil Fertility Research at IITA
• Diagnostic studies on identification
deficient nutrients in production
systems across agroecologies
• Fertilizer response studies, but mostly
on cereals (maize); limited on roots
and tubers
• Alley farming/ improved fallow (limited
adoption)
• Cereal-legume rotations (include ISFM)
• Use of phosphate rock in legume
rotation systems (limited promotion)

11. Concept of ISFM
The application of soil fertility
management practices (appropriate
fertilizer + organic input + improved
germplasm) and the knowledge to
adapt these to local conditions to
optimize fertilizer and organic
resource- use efficiency and crop
productivity

12. ISFM + Enabling environment
Integrated Soil Fertility Management Strategy
Institutions
Integrated Pest Soil Conservation
and policy
management water management
ISFM
Ecosystem
Resilient germplasm /
Services
fertilizer (Org+Inorg)
Markets

13. Vision
• Promote ISFM in cereal-legume
rotations with focus on
promiscuous soybean-maize
systems in Africa using
participatory approaches
• Integrating mineral fertilizer
component of ISFM package
based on site-specific fertilizer
balanced management practices

14. Vision cont‟d
• Integrate ISFM principles into
conservation agriculture in SSA with
linkage to climate change/ land
degradation
• Transform IITA Nutrition lab to a
center of excellence for Bio-
fortification studies

15. Vision cont‟d
• Review and establish ISFM
guidelines for roots and tubers
(particular focus on yam &
cassava)

16. Promote ISFM in cereal-legume
rotations using participatory approach
Key issues:
• Limited N-use efficient crop varieties
• Dynamic nature of N in farmers‟ fields
• Limited use of available ISFM options

17. Promote ISFM in cereal-legume
rotations using participatory approach
Experiences: N-use efficient crop varieties
(Screened maize cultivars under variable N
to identify N-efficient cultivar)

18. N Vs. Root Length Density
Source: Oikeh, Kling, Horst, & Chude (1999). Field Crop Res. 62: 1-13
0-15
Soil depth (cm)
15-30
30-45
45-60
60-75
0 g/plant
2.26 g/plant
a • N application stimulated root
production in surface soil at
1994/35 DAS
75-90 early growth stage
0 0.1 0.2 0.3 0.4 0.5
0-15
Soil depth (cm)
15-30
30-45
0 g/plant
45-60 0.56 g/plant
2.26 g/plant
• Greater root growth and
60-75 distribution observed at 30 kg N
1994/silking
75-90 ha-1 (0.56 g/plant) than at 0N or
120N
0 1 2 3 4 5 6
Root length density (cm cm-3)

19. Root Length Density of Maize varieties
Plant ht RLE DM
Cultivar (cm) (mm/day) (g/plant)
0-15 (25 DAP)
Soil depth (cm)
25-28 DAP 35DAP
15-30
EV8728 61.5 74.5 17.8
30-45
87TZPB 57.5 69.8 15.2
45-60
SPL 63.5 79.6 18.0
60-75
35 DAS 8644-27 61.3 73.9 15.2
75-90
(HYB)
0 0.1 0.2 0.3 0.4 0.5
TZB 59.5 70.8 14.3
(CTL)
LSD 1.6 3.1 2.4
TZB (p=0.1)
Soil depth (cm)
0-15
8644
15-30 • Varietal differences in RL at 35DAS
30-45 SPL
45-60 TZPB • All improved cvs. had better RL and
EV8728 growth than the check
60-75
75-90 Silking • TZPB & SPL had better root systems
0 1 2 3 4 5 6
in lower depth at silking
Root length density (cm cm-3) Source: Oikeh, Kling, Horst, & Chude (1999). Field
Crop Research. 62: 1-13

20. Phenology, grain yield, HI, and N efficiency
parameters of maize cultivars as influenced by N
ASI LGF Grain yield HI N-util. eff. N-use eff.
Cultivar (d) (d) (Mg ha-1) (%) (%) (kg grain/kg avail. N)
EV8728 3.4 48.0 5.0 40 50 18.5
87TZPB 5.3 45.6 4.8 36 46 16.6
SPL 3.1 43.4 5.0 41 50 17.4
8644-27 5.2 47.9 5.2 43 54 18.5
TZB-SR 4.2 46.1 4.7 35 45 16.6
SED 0.2* 0.5** 0.1+ 0.5** 0.7** 0.5*
CV (%) 3 3 16 9 9 20
Source: Oikeh and Horst 2001: In: W.J Horst et al. (eds.). Plant Nutrition: Food security and sustainability of agroecosystems.
Development in Plant and Soil Science Book Series. Kluwer Academic Publishers, The Netherlands.

21. Mean N uptake over time as
influenced by N
N N uptake (kg ha-1)
Cultivar (kg ha-1) 35 DAP Midsilk Grain Stover NHI (%) Total N
0 11 42 29 18 60 47
30 18 54 47 25 65 72
120 19 86 87 39 69 126
SED 1* 3** 2** 1** 1** 3**
EV8728 17 59 57 26 68 82
87TZPB 15 70 56 29 65 85
SPL 19 55 59 27 68 86
8644-27 15 63 53 26 66 79
TZB-SR 14 56 48 29 58 77
SED 1* 4* 3* 1 ns 1** 3ns
Source: Oikeh, Carsky, Kling, Chude, & Horst (2003). Agriculture Ecosystems and Environment 100: 181-191.

22. Promote ISFM in cereal-legume
rotations using participatory approach
Experiences: Dynamic nature of N in
farmers„ fields
Livelihood analysis:
 5 Villages in 3 States, NGS, Nigeria
 Major constraints as ranked by farmers:
• Low soil fertility/lack of fertilizers
• Striga hermonthica infestation
• Early season drought causing replanting

23. Patterns of NO3-N (0-30 cm)
Dynamics in 35 Farmers‟ Fields, NGS
(7 fields)
(7 fields)
(7 fields)
(14 fields)
Source: Weber, Chude, Pleysier, & Oikeh (1995). Exp. Agric. 31: 333-344.

24. Managing N Dynamics Using
ISFM Package
ISFM with Stylo
organic inputs (fallen
leaves + roots) slowed
down N mineralization
and N losses in soil-
plant system
Source: Oikeh, Chude, Carsky, Weber, & Horst (1998). Experimental Agriculture 34: 73-83

25. On-farm ISFM Package
6
1.3 Mg ha-1 yield advantage
5 from legume rotation with
Grain yield (t ha-1)
N-use eff. maize over 2-yr
4 continuous N-ineff. maize
3
2
TZB-SR (N-ineff.)
1 8644-27 (N-use eff.)
0
Maize
Soybean
Stylo
Previous crop
Source: Oikeh, Chude, Carsky, Weber, & Horst (1998). Experimental Agriculture 34: 73-83

26. Mean Mineral N Balance (loss)
160 from Soil-plant System
•
140
120
35 – 122 kg N ha-1
lost (leaching)
•
N loss (kg ha-1)
100
SPL had >
80 capacity to take up
N during
60 grainfilling period
thus minimizing N
40 losses
20 • SPL had deep fine
root system
0
87TZPB-SR
EV8728-SR
8644-27
TZB-SR
SPL
Cultivars
Nl/g = (Nup(t2) + Nmin(t2))  (Nfert + Nmin(t1) + N(rain)) Source: Oikeh, Carsky, Kling, Chude, & Horst (2003).
Agriculture Ecosystems and Environment 100: 181-191.

27. Model Maize (Ideotype)
for African Savanna (e.g. SPL)
Adapted: Oikeh, Kling, Horst, & Chude (1999). Field Crop Res. 62: 1-13
• High seedling vigor and dense root system in
surface soil at early growth stage
• Fine, deep, and dense root system late in
season with extended N absorption into
grainfilling
• Short ASI and LGF
• > one ear per plant under low N
• High grain yield and harvest index
• Good grain processing quality (Oikeh, Kling, & Okoruwa
(1998). N fertilizer management effects on maize grain quality in West Africa. Crop
Science 38:1056-1061)

28. What Next ?
• Promote grain legume-cereal ISFM
Africa-wide using participatory
approaches
• Develop new ideotypes of crops for
Africa using experience from maize
ideotype
• Use existing models to predict
nutrient flow and out-scaling ISFM
options

29. Integrating mineral fertilizer
component of ISFM options based on
site-specific FBMP
Key issues:
• Limited fertilizer recommendations
based on site-specific variability in soil
fertility
• Fertilizer applications based on crop
responses/ agroecologies lead to over
or under-application in some fields

30. Integrating mineral fertilizer
component of ISFM options based on
site-specific FBMP
Experiences: Cultivar response to fertilizer
(cultivar fertilizer) across agroecologies

31. N Vs. Dry-matter Yield
Source: Oikeh, Kling, Horst, & Chude (1997). Proceedings 5th Eastern and Southern Africa Regional Maize Conf.,
Arusha, Tanzania 3-7 June 1996. CIMMYT, Addis Ababa, Ethiopia, pp 163-167
Dry-matter Yield
16 Total
14
12
Y =8.8 + 6.0N - 1.3N2 R2=1.0
• 5 maize cultivars
screened under 4 N
Yield (t ha-1)
10 levels for 2 yrs
8 • 60 kg N ha-1
Grain adequate for maize
6 production under the
Y =2.8 + 3.5N - 0.8N2 R2=0.99 conditions of the
4
experimental site
2
0
0 30 60 90 120
Nitrogen rate
(kg ha-1)

32. NPK vs. Mean Grain Yield of 4
NERICAs Humid Forest, Nigeria
6
NERICA yield (Mg ha-1) c
60 kg/ha N
5
13 kg/ha P b
4
25 kg/ha K
3
a
2
1
0 N60-P13-K25 N120-P26-K25
Zero N60-P13-K25 N120-P26-
Fertilizer treatment K25
N60-P13-K25= 60 kg N, 13 kg P and 25 kg K per ha
N120-P26-K25= 120 kg N, 26 kg P and 25 kg K per ha.
Source: Oikeh et al. (2006). Fertilizer summit, 2006

33. What Next ?
Integrate mineral fertilizer
component of ISFM options
based on site-specific nutrient
content and crop requirement

34. Integrate ISFM principles into conservation
agriculture in SSA with linkage to climate
change/ land degradation
Key issues:
• Climate change
• Land degradation
• Declining soil fertility

35. Integrate ISFM principles into conservation
agriculture in SSA with linkage to climate
change/ land degradation
Experience: Cowpea-NERICA Ecotechnology
(example of ISFM option developed
with farmers in NGS, Benin)

36. Organic inputs
Farmer‟s 80-day Cowpea (Katchè) 75-day Dual-purpose Cowpea
85-day NERICA 8
(Resilient, N-use efficient)
+
Mineral N (20 kg ha-1)

37. Opening Ceremony of Soil Fertility Lab, WARDA Cotonou
AAS

38. Cowpea Rotation Vs. Soil-N at
21 and 42 DAS in 5 farmers‟ Fields
NO3-N (T21; kg ha-1) Nmin (T42; kg ha-1)
Rotation
Soil Depth (cm) Soil Depth (cm)
0 – 15 15 – 30 0 – 15 15 – 30
IT89KD-288 11.0 12.8 31.0 26.2
IT90-277-2 17.7 8.6 33.1 22.7
IT97-568-11 20.6 15.1 40.5 25.7
IT97K-1069-6 11.6 14.3 36.4 28.2
IT93K-452-1 15.6 13.9 28.0 23.5
Katechè (local) 12.7 8.5 25.0 27.0
Fallow 12.6 10.4 24.9 22.7
SE (Rot Depth) 2.78 3.31
Source: Oikeh, Niang, Abaidoo, Houngnandan, Koichi, Kone, & Toure (??). Cowpea-NERICA Rice Ecotechnology for
Sustainable Management of Degraded Tropical Savanna Soil. Soil Science Society of America Journal (in preparation).

39. Mean NERICA8 Yield Vs. Previous Cowpea
(5 farmers‟ fields, NGS, Benin)
1.2
1
Grain Yield (Mg.ha -1)
0.8
0.6
0.4
0.2
0
IT90-277-2 IT97-568-11 IT97K-1089-6 IT93K-452-1 Local (Katché) Fallow
•
Previous crops
Previous cowpea (IT97-568-11) + 20N gave 2.4 times > yield than
previous fallow + 0N (CTL) in Cowpea-NERICA Ecotechnology
Source: Oikeh, Niang, Abaidoo, Houngnandan, Toure & Mariko (2008). Abstract Submitted to Annual Meeting of CSA Societies, USA

40. N Fertilizer Replacement Value of
Previous Cowpea cv. IT97-568-11
2.5
26 kg/ha N replacement
Grain Yield (Mg ha -1)
2 (N savings to the farmer)
from NERICA8 Vs. N
1.5
response curve
1
0.5
0
0 10 20 30 40 50 60 70 80
N Level (kg ha-1)
Source: Oikeh, Niang, Abaidoo, Houngnandan, Toure & Mariko (2008). Abstract Submitted to Annual Meeting of CSA Societies, USA

41. What Next ?
Promote conservation
agriculture using ISFM
principles

42. Transform IITA Nutrition lab to center of
excellence for Bio-fortification studies
Key issues:
• Analyses of samples in
advanced lab
• High transaction costs in
developing micronutrients
enhanced crops

43. Transform IITA Nutrition lab to center of
excellence for Bio-fortification studies
Experience:
“Micronutrient
Enhancement of Maize to
Reduce Hidden Hunger”
Calcium
Deficiency
Ricket, WHO
Iron Deficiency Anemia, WHO

44. Summary of Findings
• Evaluated 49 late- & early-maturing
maize across 3 contrasting ecologies for
2 yrs for Fe & Zn conc.
• Mean Fe: 16.5 – 23.1 mg kg-1 Late maize
• Mean Zn: 16.1 – 23.9 mg kg-1 “
• Mean Fe: 16.9 – 20.7 mg kg-1 Early maize
• Mean Zn: 18.2 – 21.2 mg kg-1 “
• Evaluated bioavailable Fe using a Model
Gut (mimic digestive system; Glahn et al. 1996)
Sources: 1. Oikeh, Menkir, & Maziya-Dixon (2003). Journal of Plant Nutrition. 26: 2307 – 2319.
2. Oikeh, Menkir, Maziya-Dixon, Welch, Glahn, & Gauch JR. (2004). Journal of Agric. Science (Camb.). 142: 543 – 551.

45. A Cartoon of the In Vitro
Digestion/Caco-2 Cell Culture Model
(Glahn et al. 1996)
500 mg maize sample
Pepsin Digestion
pH 2, 1 h, 37 C (50 mL tube)
Insert ring
Pancreatin-Bile Digestion
Culture well pH 6.8 – 7.0, 2 h, 37 C
Dialysis membrane Soluble iron
15K MWCO
Caco-2 cells
Harvest cells for ferritin determination
24 h post start of Panc/Bile digestion

47. ANOVA of location, variety and G  E interactions
on Fe bioavailability from Early-maturing maize
% of total
variation
Pr>F
Source Fe Fe
bioav. bioav. Fe bioav.
(%) LOG (%)
Loc 0.444 0.523 <1
Var 0.006 0.029 12
VxL 0.586 0.353 10
CV 35 7
(%)
Sources: Oikeh, Menkir, Maziya-Dixon, Welch, & Glahn (2003). Journal of Agricultural and Food Chemistry 51: 3688-3694

48. Caco-2 Cell Ferritin Formation
Early-Maize (as % of Control)
175
* *
* *
Caco-2 Cell Ferritin 150
(as % of Control)
125
100 Control
(22)
75
50
25
0
3
4
2
6
5
11
8
14
1
15
9
19
13
18
20
7
16
10
17
12
Variety
Sources: Oikeh, Menkir, Maziya-Dixon, Welch, & Glahn (2003). Journal of Agricultural and Food Chemistry 51: 3688-3694

49. What Next ?
Back-stop breeders to
develop and promote
micronutrient enhanced
crops at IITA

50. Review and establish ISFM
guidelines for roots and tubers
Key issue:
Limited studies on improving soil
fertility for roots and tubers in Africa

51. Review and establish ISFM
guidelines for roots and tubers
Experience: None!

52. What next?
 Literature review on soil fertility studies
on roots and tubers
 Conduct ISFM studies on roots and tubers
 Develop ISFM guidelines for roots and
tubers production in Africa

53. Resource Mobilization Efforts
(2006-2008)
Project Donor Value Partner
Smallholder rice-based livelihood and UNDP $ 5.0m Min. of Agric.
income enhancement project for Liberia Liberia/WARD
A/IITA/ AVRDC
Alleviating rural poverty through IFAD $ 1.5m IRRI/WARDA
improving rice production in E. & S.
Africa
Enhancing smallholder access to IFAD $ 1.5m WARDA
NERICA seed for alleviating rural
poverty in WCA
Development of sustainable rice MOP $ 0.18m WARDA
farming systems in LAC soils in West Japan
African lowlands: Nutrients cycling in
sawah vs. non-sawah rice farming
systems
NUE Rice for Africa USAID $4.0m AATF/ARCAR
DIA/ WARDA

54. Conclusion
The vision of African Leaders: “to
increase the fertilizer use from 8 to 50 kg
ha-1 nutrients by 2015” (Fertilizer
Summit, 2006) can only be actualized
with the right enabling environments,
with the right people in the right places

55. Thank you!
Merci!!
Asante sana!!!
Eshe‟o!!!!