Presentation delivered at the CIALCA international conference 'Challenges and Opportunities to the agricultural intensification of the humid highland systems of sub-Saharan Africa'. Kigali, Rwanda, October 24-27 2011.

1. Exploring the scope of fertilizer use in the
East African region
Wairegi, L.W., van Asten, P.J.A.

2. Introduction
● Data sources: FAOSTAT 2008/2009, AMITSA,
personal communication.
● Moisture content: Maize (14%), Beans (12%),
Banana (84%), Cassava (62%), Rice (12%),
Coffee (12%)
● Nutrient recovery: 50% for N, 15% for P and
60% for K of fertilizer applied

3. Proportion of arable land under crops (%)
Burundi DRC Kenya Rwanda Uganda Tanzania
Maize 13 22 33 11 13 30
Beans 24 3 15 26 14 12
Bananas 31 5 2 27 27 8
Cassava 7 28 1 11 6 10
Rice 3 6 0* 1 2 8
Coffee 2 1 3 3 5 1
Total 80 65 54 79 67 69
* 0.4%
Rice refers to paddy rice

4. Nutrients (kg) required to produce 1t edible DM yield
Residue Edible yield
120
90
Nitrogen 60
30
0
Maize Beans Banana Cassava Rice Coffee
8
6
Phosphorus 4
2
0
Maize Beans Banana Cassava Rice Coffee
120
90
Potassium 60
30
0
Maize Beans Banana Cassava Rice Coffee

5. Fertilizer (Kg) required to replenish nutrients taken up (for 1t edible
drymatter)
1000
Urea TSP Muriate of potash
800
600
400
200
0
Maize Beans banana cassava Rice Coffee

6. Yields and estimated nutrients in edible yield in the region
Yield N P K Total
(t/ha) (Kg) (Kg) (Kg) (kg)
Maize 1.0 18 4.2 7 29
Beans 0.6 27 2.2 17 46
Bananas 1.0* 11 1.2 31 43
Cassava 2.8 21 3.0 33 56
Rice 2.3 30 5.9 6 42
Coffee 0.5 13 1.0 11 24
*Burundi not included
Averages for 2008 and 2009
Reference: FAOSTAT, 2011

7. Examples of inputs used in the region
Burundi DRC Kenya Rwanda Uganda Tanzania
Fertilizer 0.6 0.1 50.6 3.4 0.8 7.5
consumption
(kg/ ha arable land)

8. Prices!

9. Average prices (USD) of 1t edible yield (dry matter)
4000 Maize Beans Banana
Cassava Rice Arabica coffee
3000
2000
1000
0
Burundi DRC Kenya Rwanda Tanzania Uganda

10. Fertilizer prices (USD)
Burundi DRC* Kenya Rwanda Uganda Tanzania
Urea 754 1250 534 540 712 563
TSP 1000 1250 806 675 853 773
MOP 1000 1250 705 567 853 773
* South Kivu

11. Ratio between price of 1t edible yield and cost of fertilizer
a) Based on total above ground biomass
10
Burundi DRC Kenya Rwanda Tanzania Uganda
8
6
4
2
0
Maize Beans Banana Cassava Rice Coffee
*Robusta coffee 1.3 in DRC and 2.0 in Uganda

12. Ratio between price of 1t edible yield and cost of fertilizer
b) Based on nutrients removed in edible yield
20 burundi DRC kenya rwanda tanzania uganda
15
10
5
0
Maize Beans Banana Cassava Rice Coffee
*Robusta coffee 4.3 in DRC and 7.6 in Uganda

13. How change in crop price affects ratio
Rice
6 a) Burundi Arabica coffee
Banana
4 Beans
Cassava
2 Maize
Price of 0
1t yield/
Fertilizer 0 50 100 150 200 250
cost Arabica coffee, Rice
6 b) Uganda Robusta coffee
4 Banana
Beans, Cassava
2
Maize
0
0 50 100 150 200 250
Price of 1t yield (% of average)

14. How change in fertilizer price affects ratio
a) Burundi
8 Rice
6 Arabica coffee
Banana
4 Beans, Cassava
2 Maize
Price of 0
1t yield/ 0 50 100 150 200 250
Fertilizer
cost b) Uganda
8 Arabica coffee, Rice
6 Robusta coffee
Banana
4 Beans, Cassava
2 Maize
0
0 50 100 150 200 250
Cost of fertilizer required for 1t yield (% of average)

15. If beans fix 50% N and residues are retained in field…
Fixed N by bean crop yielding 1t can meet
requirements for:
0.5
0.4
0.3
Yield
(t/ha) 0.2
0.1
0
Maize Banana Cassava Rice Coffee

16. Conclusion and outlook
● Coffee and rice are the best for use of mineral fertilizer and
maize is the worst – this seems contrary to the current
practice!
● Fertilizer use is attractive in countries with “cheap” fertilizer (for
farmers) compared with countries where fertilizer is more expensive.
Investigate cost-effectiveness of subsidies at a national level.
● This study is a simplified approach for exploratory purpose ->
however, ISFM and crop mixtures can improve efficiency/profitability
● There is need and scope for fertilizer use in the East African
region, but choice of crop for intensification, and decision on amount
and type of fertilizer should depend on input/output prices, crop
residue management, and crop response.

17. Conclusions and outlook
● Need to fine-tune mapping of “economic” benefits of
fertilizer use amongst crop within the countries, as function
of spatial variation of input/output prices.
● Need to equip farmers with simple decision support tools
that can aid in making decisions on what crop to intensify
in, type of inputs to use, management practices

18. THANK YOU
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