TSBF
Fertility
Soil
Biology
B Vanlauwe
TSBF-CIAT
Kenya, Nairobi
b.vanlauwe@cgiar.org
Integrated soil fertility management:...
TSBF
Fertility
Soil
Biology
B Vanlauwe
TSBF-CIAT
Kenya, Nairobi
b.vanlauwe@cgiar.org
Integrated Soil Fertility
Management:...
 Finally, fertilizer is back on the African research
for development agenda! [though the pro-organic
agriculture voice & ...
 Soils are old; limited rejuvenation
Production environment in Africa
 Only about 10% of the arable land in use
Production environment in Africa
 Only about 10% of the arable land in use
[limited areas with large population densities]
Production environment in Africa
 Lack of infrastructure, market organization
Production environment in Africa
Mombasa
264 USD
Masaka
(Uganda)
421 USD
International
market
165 USD
 Lack of infrastructure, market organization
Product...
Production environment in Africa
 Lack of favorable policy [e.g, Nigeria: subsidies
have been on/off over the past 30 years]
 Declining capacity in R&D f...
FAO Index of Net Food Output per Capita, 1961-2000
80
90
100
110
120
130
140
150
160
1961
1963
1965
1967
1969
1971
1973
19...
Necessary components of ISFM
1. Fertilizers are indispensable
Necessary components of ISFM
2. Organic resources are limited but necessary
Crop Oilpalm Imperata Manure
residues leaves
A...
Necessary components of ISFM
3. Improved germplasm enhances nutrient uptake
Necessary components of ISFM
4. Fields are
heterogeneous
Good soil – same farm
Poor soil – same farm
‘The application of soil fertility management
practices, and the knowledge to adapt these to
local conditions, which maxim...
Agronomic efficiency
= [Increase in yield]/[Fertilizer nutrients applied]
Definition of ISFM
0
500
1000
1500
2000
2500
300...
Agronomic efficiency
= [Increase in yield]/[Fertilizer nutrients applied]
Definition of ISFM
0
500
1000
1500
2000
2500
300...
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
Step 1: Fertilizer and germplasm
0
1000
2000
3000
low medium high
manage me nt
maizeyield[kgha
-1
]
control (no fertilizer...
Early
Specific
variety
Dual
purpose
variety
Step 1: Fertilizer and germplasm
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
Source: Vanlauwe et al, PLSO, 2010
Step 1: Fertilizer and germplasm
0
5
10
15
20
25
30
Local Improved - OPV Improved -
Hyb...
Step 1: Fertilizer and germplasm
Soil C issues Zimbabwe, clayey soils
Source: Zingore al,
EJSS, 2005
Important research issues
Site (country) Fert Duration Organic C (g kg-1)
years - Fert + Fert Diff.
Zaria (Nigeria) AS 15 ...
Total millet dry matter yield as affected by long-term
application of crop residues and fertilizer, Sadore, Niger
0
1000
2...
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
Step 2: Combining fert and OM
Source: Vanlauwe et al,
PLSO, 2010
Site (years) Source of organic
matter
Organic C (g kg-1)
None Fert OM Fert
+OM
Ibadan (10) ACa with Leucaena 5.9 5.8 9.7 9...
0
10
20
30
40
50
SoilC(gCkg-1
soil)
Silt and clay
Microaggregates
Macroaggregates
Control T. diversifolia C. calothyrsus Z...
Source: Vanlauwe et al, PLSO, 2010
Step 3: Adaptation to local conditions
0
500
1000
1500
2000
2500
3000
Infield Outfield
...
Step 3: Adaptation to local conditions
IF acid soil THEN apply lime
IF soil crusting THEN superficial tillage
IF plow laye...
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
Step 3: Adaptation to local conditions
Occurrence of non-responsive soils!
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
Agronomicefficiency
Current
practice
Germplasm
& fertilizer
+ Organic
resource mgt
+ Local
adaptation
Germplasm
& fertiliz...
An enabling environment for ISFM
 AE within the ISFM is based on short term gains
 Focus on productivity… but indications that
soil C can also be increas...
1. This is the time for soil science and plant
nutrition to show impact in Africa; ISFM will drive
investments in soil fer...
1. This is the time for soil science and plant
nutrition to show impact in Africa; ISFM will drive
investments in soil fer...
1. This is the time for soil science and plant
nutrition to show impact in Africa; ISFM will drive
investments in soil fer...
1. This is the time for soil science and plant
nutrition to show impact in Africa; ISFM will drive
investments in soil fer...
1. Under which conditions (population, soil,
markets, etc) can ISFM be the model for
intensification?
Questions for a frui...
1. Under which conditions (population, soil,
markets, etc) can ISFM be the model for
intensification?
2. Is fertilizer a v...
1. Under which conditions (population, soil,
markets, etc) can ISFM be the model for
intensification?
2. Is fertilizer a v...
1. Under which conditions (population, soil,
markets, etc) can ISFM be the model for
intensification?
2. Is fertilizer a v...
Thank you!
Merci beaucoup!
Asante sana!
Integrated soil fertility management: definition and impact on productivity and soil C
Integrated soil fertility management: definition and impact on productivity and soil C
Integrated soil fertility management: definition and impact on productivity and soil C
Integrated soil fertility management: definition and impact on productivity and soil C
Integrated soil fertility management: definition and impact on productivity and soil C
Integrated soil fertility management: definition and impact on productivity and soil C
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Integrated soil fertility management: definition and impact on productivity and soil C

  1. 1. TSBF Fertility Soil Biology B Vanlauwe TSBF-CIAT Kenya, Nairobi b.vanlauwe@cgiar.org Integrated soil fertility management: definition and impact on productivity and soil C ABSTRACT Traditional farming systems in sub-Saharan Africa depend primarily on mining soil nutrients. The African Green Revolution aims at intensifying agriculture through dissemination of Integrated Soil Fertility Management (ISFM). In this paper we develop a robust and operational definition of ISFM, based on detailed knowledge of African farming systems and their inherent variability and of optimal use of nutrients. We define ISFM as ‘A set of soil fertility management practices that necessarily include the use of fertilizer, organic inputs, and improved germplasm combined with the knowledge on how to adapt these practices to local conditions, aiming at maximizing agronomic use efficiency of the applied nutrients and improving crop productivity. All inputs need to be managed following sound agronomic principles.’ Issues that will be covered in this paper include: (i) the use of mineral fertilizer and expected responses under varying soil conditions, (ii) the use of locally available organic inputs in combination with fertilizer, and (iii) the integration of legume species in rice-based systems, including aspects of improved agronomy. Examples are given for specific African farming systems with high potential for adoption of ISFM, including sorghum and millet based systems in the Sahel, legume-maize systems in the savanna, and cassava-based systems in the humid forest. For each above theme, both issues of crop productivity and soil carbon stocks and dynamics will be covered. Finally, the conditions that enable the adoption of ISFM, including access to markets and appropriate policy, are also discussed.
  2. 2. TSBF Fertility Soil Biology B Vanlauwe TSBF-CIAT Kenya, Nairobi b.vanlauwe@cgiar.org Integrated Soil Fertility Management: definition and impact on productivity and soil C
  3. 3.  Finally, fertilizer is back on the African research for development agenda! [though the pro-organic agriculture voice & no-to-fertilizer voices are still heard!]  Statement in 1996 (Research Director, IITA): ‘You can’t include fertilizer in your work since farmers in Africa are not using fertilizer’  The Alliance for a Green Revolution in Africa (AGRA) (headed by K Anan): ‘By 2015, increase fertilizer use from 8 to 50 kg fertilizer nutrients/ha’  Soil health program of AGRA [50% improved plants, 50% improved soils] The opportunity…
  4. 4.  Soils are old; limited rejuvenation Production environment in Africa
  5. 5.  Only about 10% of the arable land in use Production environment in Africa
  6. 6.  Only about 10% of the arable land in use [limited areas with large population densities] Production environment in Africa
  7. 7.  Lack of infrastructure, market organization Production environment in Africa
  8. 8. Mombasa 264 USD Masaka (Uganda) 421 USD International market 165 USD  Lack of infrastructure, market organization Production environment in Africa Bukavu (DRCongo) 900 USD
  9. 9. Production environment in Africa
  10. 10.  Lack of favorable policy [e.g, Nigeria: subsidies have been on/off over the past 30 years]  Declining capacity in R&D for soil fertility mgt  Insufficient investment in agricultural R&D  Brain drain  Climate change, drought  Civil strife  HIV/AIDS, malnutrition  Land tenure insecurity  High inflation, low salaries  Etc, etc, etc Production environment in Africa
  11. 11. FAO Index of Net Food Output per Capita, 1961-2000 80 90 100 110 120 130 140 150 160 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 World E SE Asia South Asia Sub-Sahara Current status of agriculture in Africa
  12. 12. Necessary components of ISFM 1. Fertilizers are indispensable
  13. 13. Necessary components of ISFM 2. Organic resources are limited but necessary Crop Oilpalm Imperata Manure residues leaves Availability? Acceptability? Quality?
  14. 14. Necessary components of ISFM 3. Improved germplasm enhances nutrient uptake
  15. 15. Necessary components of ISFM 4. Fields are heterogeneous Good soil – same farm Poor soil – same farm
  16. 16. ‘The application of soil fertility management practices, and the knowledge to adapt these to local conditions, which maximize fertilizer and organic resource use efficiency and crop productivity. These practices necessarily include appropriate fertilizer and organic input management in combination with the utilization of improved germplasm’ Definition of ISFM
  17. 17. Agronomic efficiency = [Increase in yield]/[Fertilizer nutrients applied] Definition of ISFM 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 0 50 100 150 200 Fertilizer nutrients applied (kg/ha) Cropyield(kg/ha)
  18. 18. Agronomic efficiency = [Increase in yield]/[Fertilizer nutrients applied] Definition of ISFM 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 0 50 100 150 200 Fertilizer nutrients applied (kg/ha) Cropyield(kg/ha)
  19. 19. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/  Average of 8 kg nutrients/ha  Relatively poor AE due to poor fertilizer management  Lack of use of improved germplasm Current practice
  20. 20. Step 1: Fertilizer and germplasm 0 1000 2000 3000 low medium high manage me nt maizeyield[kgha -1 ] control (no fertilizer applied) fertilizer applied Maizegrainyield(kg/ha) Management regime Management intensity (planting date, crop density and time of phosphorus application), Tinfouga, Mali (Bationo et al., 1997).
  21. 21. Early Specific variety Dual purpose variety Step 1: Fertilizer and germplasm
  22. 22. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/ Step 1: Fertilizer and germplasm
  23. 23. Source: Vanlauwe et al, PLSO, 2010 Step 1: Fertilizer and germplasm 0 5 10 15 20 25 30 Local Improved - OPV Improved - Hybrid N-AE(kggrainkg-1 N) Average SED
  24. 24. Step 1: Fertilizer and germplasm Soil C issues Zimbabwe, clayey soils Source: Zingore al, EJSS, 2005
  25. 25. Important research issues Site (country) Fert Duration Organic C (g kg-1) years - Fert + Fert Diff. Zaria (Nigeria) AS 15 3.1 3.4 -0.3 Ife (Nigeria) AS 7 8.0 8.5 +0.5 Ibadan (Nigeria) AS 5 8.7 10.5 +1.8 Ife (Nigeria) AS 14 5.7 3.5 -2.2 Bouaké (Côte d’Ivoire) Urea 20 13.5 8.3 -5.2 Ibadan (Nigeria) Urea 5 8.7 9.0 +0.3 Ibadan (Nigeria) Urea 14 5.9 5.8 -0.1 Ife (Nigeria) Urea 14 5.7 8.0 +2.3 Ibadan (Nigeria) CANa 5 8.7 10.4 +1.7 Mokwa (Nigeria) CAN 12 3.1 3.3 +0.2 Ife (Nigeria) CAN 14 5.7 6.5 +0.8 Soil C issues
  26. 26. Total millet dry matter yield as affected by long-term application of crop residues and fertilizer, Sadore, Niger 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 1982 1984 1986 1988 1990 1992 1994 1996 Year Totalmilletdrymatter(kgha -1 ) Control Crop residues Fertilizer Crop residues + fertilizer 0 20 40 60 80 100 120 without crop residues with crop residues Drymatter/Napplied(kgkg -1 ) Step 2: Combining fert and OM
  27. 27. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/ Step 2: Combining fert and OM
  28. 28. Step 2: Combining fert and OM Source: Vanlauwe et al, PLSO, 2010
  29. 29. Site (years) Source of organic matter Organic C (g kg-1) None Fert OM Fert +OM Ibadan (10) ACa with Leucaena 5.9 5.8 9.7 9.3 Ibadan (10) AC with Senna 5.9 5.8 10.0 9.7 Ibadan (10) Rotation + Mucuna 5.9 5.8 7.4 8.3 Zaria (45) External Manure 3.3 2.9 5.0 5.0 Saria (18) External Manure 2.5 2.4 NA 3.5 Average 4.7 4.5 8.0 7.2 Step 2: Combining fert and OM Soil C issues
  30. 30. 0 10 20 30 40 50 SoilC(gCkg-1 soil) Silt and clay Microaggregates Macroaggregates Control T. diversifolia C. calothyrsus Z. mays b a a a Soil C contents of three aggregate size fractions (macroaggregates (>250 µm), microaggregates (53-250 µm), and silt and clay (<53 µm)) after 3 years of 4 Mg litter-C ha-1 yr-1 input (no input, T. diversifolia, C. calothyrsus, and Z. mays) in a maize cropping system in Central Kenya. Source: Gentile et al, 2010 Step 2: Combining fert and OM Soil C issues
  31. 31. Source: Vanlauwe et al, PLSO, 2010 Step 3: Adaptation to local conditions 0 500 1000 1500 2000 2500 3000 Infield Outfield Controlmaizeyield(kgha -1 ) SED (a) 0 5 10 15 20 25 30 35 40 45 Infield Outfield N-AE(kggrainkg -1 N) SED (b)
  32. 32. Step 3: Adaptation to local conditions IF acid soil THEN apply lime IF soil crusting THEN superficial tillage IF plow layer THEN deep tillage IF drought THEN water harvesting IF … THEN …
  33. 33. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/ Step 3: Adaptation to local conditions
  34. 34. Step 3: Adaptation to local conditions Occurrence of non-responsive soils!
  35. 35. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/ Step 3: Adaptation to local conditions
  36. 36. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/ Increase in complexity
  37. 37. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/ Increase in complexity Complete ISFM??? - Improved fallows - Agroforestry systems - Biomass transfer systems - ??? - ???
  38. 38. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/ Increase in complexity ‘Simple’ approaches - Demonstrations - Information folders - Diagnosis non- responsive fields - Supply chain issues - [Partial] subsidy
  39. 39. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/ Increase in complexity The Malawi fertilizer subsidy programme - Fertilizer + seed starter packs - From net importer to net exporter (2006) -AE is 14 kg grain/kg fertilizer nutrient
  40. 40. Agronomicefficiency Current practice Germplasm & fertilizer + Organic resource mgt + Local adaptation Germplasm & fertilizer’ + Organic resource mgt Germplasm & fertilizer ‘Full ISFM’ Move towards ISFM Increase in knowledge Responsive soils Poor, less-responsive soils A B C Yield/ Increase in complexity ‘Simple’ approaches - Demonstrations - Information folders - Diagnosis non- responsive fields - Supply chain issues - [Partial] subsidy Intensive approaches - Farmer capacity - Farmer field schools - Interactive learning - Diagnosis SF status - Best-fit options - Extension training
  41. 41. An enabling environment for ISFM
  42. 42.  AE within the ISFM is based on short term gains  Focus on productivity… but indications that soil C can also be increased (soil-based ecosystem services)  It is difficult to achieve complete ISFM; probably a realistic goal should be to ‘move towards’ rather than achieving complete ISFM everywhere  Local diagnosis is crucial for local adaptation Limitations to the AE concept
  43. 43. 1. This is the time for soil science and plant nutrition to show impact in Africa; ISFM will drive investments in soil fertility focusing on resource-use efficient agriculture! Take home messages
  44. 44. 1. This is the time for soil science and plant nutrition to show impact in Africa; ISFM will drive investments in soil fertility focusing on resource-use efficient agriculture! 2. The AE concept works; fertilizer as an entry point towards agricultural intensification in SSA Take home messages
  45. 45. 1. This is the time for soil science and plant nutrition to show impact in Africa; ISFM will drive investments in soil fertility focusing on resource-use efficient agriculture! 2. The AE concept works; fertilizer as an entry point towards agricultural intensification in SSA 3. Moving towards complete ISFM: immediate impact is possible while investments in capacity building for complete ISFM are happening Take home messages
  46. 46. 1. This is the time for soil science and plant nutrition to show impact in Africa; ISFM will drive investments in soil fertility focusing on resource-use efficient agriculture! 2. The AE concept works; fertilizer as an entry point towards agricultural intensification in SSA 3. Moving towards complete ISFM: immediate impact is possible while investments in capacity building for complete ISFM are happening 4. Creating an enabling environment for ISFM Take home messages
  47. 47. 1. Under which conditions (population, soil, markets, etc) can ISFM be the model for intensification? Questions for a fruitful debate
  48. 48. 1. Under which conditions (population, soil, markets, etc) can ISFM be the model for intensification? 2. Is fertilizer a valid entry point to improve soil fertility and soil C status and ensure longer term productivity increases? Questions for a fruitful debate
  49. 49. 1. Under which conditions (population, soil, markets, etc) can ISFM be the model for intensification? 2. Is fertilizer a valid entry point to improve soil fertility and soil C status and ensure longer term productivity increases? 3. How do we diagnose and manage non-responsive soils? Questions for a fruitful debate
  50. 50. 1. Under which conditions (population, soil, markets, etc) can ISFM be the model for intensification? 2. Is fertilizer a valid entry point to improve soil fertility and soil C status and ensure longer term productivity increases? 3. How do we diagnose and manage non-responsive soils? 4. At which scale should ISFM recommendations be developed (variation at different scales)? Questions for a fruitful debate
  51. 51. Thank you! Merci beaucoup! Asante sana!

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