The document discusses improving soil fertility and nutrient management in developing countries. It covers topics such as world fertilizer consumption trends from 1961-2002, the role of fertilizers in the Green Revolution, impacts of fertilizers on soil organic matter and the environment, and challenges with nutrient management in different regions of Asia and Africa. In particular, it notes that while fertilizer use has increased crop production globally, Africa has seen less progress and still struggles with widespread phosphorus and micronutrient deficiencies in many countries.

1. Improving Soil Fertility and
Nutrient Management in
Developing Countries
K.F. Bronson
Texas A&M and Texas Tech University

2. Outline
• World fertilizer consumption/crop production
– 1961-2002/malnutrition
• Green revolution & fertilizer
• Soil organic matter build-up & fertilizer
• Fertilizers and the environment
• Nut mgt in Asia
-- Central Asia
-- South Asia
-- SE Asia
• Nut mgt in Africa
-- West Africa
• Future needs for research and outreach

3. Fertilizer use and crop
production worldwide

4. World cereal production and total fertilizer
2500 160
consumption, 1961-2002 (FAOSTAT)
140
2000
Fertilizer consumption (mill Mt)
120
Cereral production (mill Mt)
100
1500
80
Cereal production
1000 Fertilizer consumption 60
40
500
20
0 0
1961 1964 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000
Africa is an exception Year

5. Production
per capita
and
Production
Area per
capita

6. Percent of population malnourished for 1990-2001
45
40
35
Percent of pop undernourished
30
1990-1992
25 1999-2001
20
15
10
5
0
Devg Asia India Bang China Indo Sub-Africa Niger Mali S.A. Brazil Colum
Countries

7. Calories/person/day for 1990-2001
3500
3000
1990-1992
1999-2001
2500
Calories/person/day
2000
1500
1000
500
0
Devg Asia India Bang China Indo Sub-Africa Niger Mali S.A. Brazil Colum
Countries
Note: World avg 2700-2800 cal, USA avg 3500-3800 cal

8. Fertilizer and the green
revolution

9. Response of tall, traditional rice and semi-dwarf rice to
N fertilizer, Philippines, 1968
10.00
9.00
8.00
7.00
Grain yield (t/ha)
6.00
5.00
Tall, native variety
IR8
4.00
3.00
2.00
1.00
0.00
0 20 40 60 80 100 120
Nitrogen rate (kg/ha)

11. “African Exception” (Avery, 2000)
• Africa has been low population with low
input/low yield bush fallow. 25 % good
cropland not used
• Green revolution efforts targeted Asia,
were not transferable to Africa
• Poor record keeping
• Poor governance

12. Why hasn’t the green revolution been
successful in Africa? (Evenson&Gollin)
• No elite germplasm for cassava, beans
sorghum, millet
• Crops are more diverse & mostly dryland
• Large landholdings for cash crops

13. Fertilizer and soil organic matter

15. Total soil organic C and total soil N in 0-15 cm
Inceptisol after 30 yr of rice-wheat-jute cropping,
West Bengal, India (Manna et al., 2006)
Nutrient
Total organic C Total N
management
g/kg mg/kg
Control 5.1 c 422 f
N 5.7 d 660 d
NP 6.3 c 750 c
NPK 7.4 b 867 b
NPK + FYM 7.9 a 927 a

17. Crop residue removal

18. Advantages of organic manures
• Boost yields, retard yield declines
• Provide N, P, micronutrients
• Fortify seeds with micronutrients
• Build-up soil organic matter
• Improve soil physical properties
• Improve soil water relations

19. Limitations of organic manures
• Availability/transport costs
• Nutrient imbalance (i.e. manure is about
2:1 N:P2O5, plants need 5-7:1 N:P2O5)
• Variability in composition
• Potential for polluting surface waters
• Limited nutrient availability in 1st year
• Pathogens

20. Fertilizer and the environment

21. Nitrous oxide fluxes in irrigated rice as affected
by N fertilizer source and mid-season drainage,
4
Los Banos, Philippines, 1993 dry season.
3.5
3
2.5
N2O (mg N/m2/d)
2
1.5
Urea
Ammonium sulfate
1
0.5
0
0 20 40 60 80 100 120
-0.5
Days after transplanting

22. Methane fluxes in irrigated rice as affected by
N fertilizer source and mid-season drainage,
Los Banos, Philippines, 1993 dry season.
40
35
30
CH4 flux (mg C/m2/d)
25
20 Urea
Ammonium sulfate
15
10
5
0
0 20 40 60 80 100 120
-5
Days after transplanting

23. Cadmium content of phosphate rock
mg /kg mg/kg P2O5
Igneous Deposits
South Africa 1 3
Former USSR 1 3
Sedimentary Deposits
China 2 7
Morocco 26 80
Senegal 87 241
North Florida 6 20
North Carolina 38 128
Western US 92 292

24. Other environmental issues
• Eutrophication of surface waters
• Nitrate contamination of surface and
ground waters
• Arsenic contamination of groundwater
• Aral Sea crisis

25. Soil Fertility in Asia

26. Fertilizer use and grain production in India
160 20
18
140
Rice and wheat production (milln Mt)
16
Fertilizer cionsuption (milln Mt)
120
14
100
12
80 10
8
60
6
40 Rice production
Wheat production 4
20 Fertilizer consumption
2
0 0
19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 20 20
67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 01 03
Year

29. Chlorophyll meter and leaf color chart for in-
season N monitoring in Asia

30. Rice grain yields as affected by
chlorophyll meter-based management,
Ludhiana, India, 1997
N Total N Cultivar
management applied
kg N/ ha PR-106 PR-111
---------- Mg ha-1 -----------
Well-fertilized
240 5.80 a 7.02 a
reference
Chlorophyll
90 6.08 a 6.51 a
meter-based
Fixed-timing 120 6.14 a 6.54 a
Zero-control 0 4.42 b 4.72 b

31. Urea and single
superphosphate fertilization
in Eastern Uzbekistan

33. Uzbek farmers fertilization survey
• What is your cotton seeding rate (kg/ha)? 60
• What is your seedcotton yield goal (t/ha)? 2.9
• How much total urea do you apply (kg/ha)? 488
• How much superphosphate do you apply (kg/ha)?
421
• How much potash do you apply (kg/ha)? 32

34. Uzbek farmers’ survey for wheat
• What is your wheat seeding rate (kg/ha)? 250
• What is your yield goal (t/ha) ? 4.3
• How much urea do you apply (kg/ha)? 452
• How much superphosphate do you apply (kg/ha)?
419
• How much potash do you apply (kg/ha)? 3
• How often is your soil sampled and tested at the
local lab? No (100%)

35. Soil test results from three districts in Ferghana
valley, March, 2003
Quva (11) Bagdod (12) Okhunboboev (12)
Low Med High Low Med High Low Med High
Nitrate 100% 100% 66% 34%
P 55% 45% 100% 34% 34% 34%
K 18% 82% 100% 100%
1:1 pH 7.7 (0.4) 8.1 (0.2) 8.0 (0.2)
ECa
6.0 (0.6) 2.0 (0.2) 1.8 (0.3)
(mmo/cm)
a
irrigation water

36. Establishment of N and P fertilizer
rate trials in 2005
• Three locations (Quva, Ristan, and Bagdod)
• Soil tests (LaMotte) done 0-15 cm
• RCB design, N x P factorial, three reps
• Plot size 15 M x 8 (0.09 m rows)
• Urea-N rates of 0, 80, 160, and 240 kg N/ha
• Single superphosphate rates of 0, 45, and 90 kg
P2O5/ha

39. Nutrient management
recommendations for
Uzbekistan
• Farmers are applying ~ 2 X the N and P
fertilizer needed for the yield levels.
• Fertilizer timing can probably be simplified.
Phosphorus can be applied just once, pre-
plant. Urea applications might be reduced
to two splits (pre-plant and squaring).
• Recommend N and P fertilizer rate trials.

40. Soil Fertility in
Afghanistan
• Soil pH ranges from
7.5-8.8 (Mean 8.2)
• CaCO3 ranges 3-42%
(Mean 23%)
• Phosphorus and deficiencies are widespread.
• 46 % soils < 10 ppm Olsen-P
• 66 % soils < 0.5 ppm DTPA-Zn
• Potassium is generally adequate

41. Fertilizer use
• Only on irrigated fields, mainly wheat
• Average of 152 kg diammonium phosphate
(18-46-0) (27 kg N/ha, 70 kg P2O5/ha)
• Average of 150 kg urea/ha (70 kg N/ha) in
two splits
• Infrequent response – reasons?
• Little manuring

43. Cereal production in Afghanistan, 1964-2003 (FAO, 2003)

44. Challenges for future of agriculture in
Afghanistan – Soil & Crop Mgt
• Cash crop replacement for opium poppy
• Research no-till wheat for dryland
• Inexpensive implements to band P fertilizer
• Access to Zn fertilizer
• Rebuild cotton gins for cotton production
• Training of agric. Scientists (undergraduate
and graduate level)

45. Soil Fertility in Africa

46. Production
per capita
and
Production
Area per
capita

47. Agronomically, what has changed in
40-50 years?
• SoilP levels have probably decreased overall if
~5 kg P/ha is removed per year
•Expansion into more marginal lands
•Yield has decreased
•Fallow frequency and duration have decreased
•Other problems associated with land degradation,
e.g. soil crusting, wind and water erosion, etc.,
increase.

48. Soil nutrient depletion
in Africa,
Smaling et al., 1997

49. Consumption, production, export, and import of mineral
fertilizer in Sub-Saharan Africa 1988-1999 (IFDC Website)
1988/89: 1,182,000 mt 1998/1999: 1,282,000 mt
Totals for 1990- 1991- 1992- 1993- 1994- 1995- 1996- 1997- 1998- 1999- 2000-
Sub-Saharan 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
Africa
(x 1000 mt N + P2O5+K2O)
Consumption 1246 1267 1287 1341 1212 1073 1305 1252 1232 1303 1230
Production 547 543 573 539 376 348 327 272 314 296 167
Exports 207 190 179 171 134 110 95 117 157 103 83
Imports 1058 933 1096 1090 1026 827 1216 1162 1160 1146 1164
Despite recognition of acute P and other nutrient deficiencies for ~ 50 y, no real
sign of progress in fertilizer consumption

50. Improving Crop Production under low
soil P fertility
• Regional Phosphate Rock
• Partially acidulated PR
• Water soluble P fertilizers (SSP, TSP)
-- Regional SSP/TSP production
-- Import SSP/TSP/DAP
• Genetic Approach
• Agroforestry/VAM

51. Geologic Irony
Bationo,Christianson, and
Mokwunye, 1989.

52. Grain yields as affected by Kodjari phosphate rock
(PR) and TSP, Burkina Faso (Frederick et al., 1992)
Millet Sorghum Maize
Phosphorus
------------------------ kg/ha -------------------------
Treatments
Control 596 916 2219
PR 698 (68) 1006 (39) 2464 (35)
PAPR 728 (88) 1103 (81) 2839 (88)
TSP 745 1146 2919
RAE (relative agronomic effectiveness are in parentheses)

53. Grain and seedcotton yields as affected by Tilemsi
phosphate rock (PR) and SSP, Mali, 1989-1992
(Bationo et al., 1997)
SSP Tilemsi PR
Sougoumba ------------- kg/ha ---------------
Sorghum 1.43 (11)a 1.52 (27)a
Cotton 1.42 (33) 1.39 (55)
Tinfounga
Maize 2.61 (22) 2.26 (27)
Cotton 1.61 (33) 1.41 (55)
aP source rates in kg P/ha/yr are in parentheses

54. Agroforestry
Faidherbia albida
African winterthorn/Mimosa –
VAM&Bradyrhizobium

55. Soil available P as affected by
distance from Faidherbia albida
30
Payne et al Crop
Soil depth
BRAY I P (mg kg-1)
Sci. 38:1585-1591.
20 100 cm
50
20
10
0
0 5 10 15
DISTANCE (m)

56. Needs for soil fertility
research/education/capacity
building

57. Research/extension education/capacity
building needs for improving soil fertility &
nutrient management
• India/South Asia – More balanced fertilization, more
manure and residue
• Afghanistan – Cotton, hort crops, P, micronutrients
• Uzbekistan – more efficient irrig., rationalize N and P,
i.e. less application/more for export
• Southeast Asia – improve NUE in rice w/LCCs,
urea briquettes, green manures, P, animal manure
• West Africa – PAPR, N, lime, HYVs, animal waste
• Training of agric. Scientists (undergraduate,
graduate/post-docs/visiting)