Digital Soil Mapping: soil fertility status and fertilizer recommendation for Ethiopian agricultural land

1. ETHIOPIAN DEVELOPMENT
RESEARCH INSTITUTE
Digital Soil Mapping: soil fertility status and
fertilizer recommendation for Ethiopian
agricultural land
Hailu Shiferaw
IFPRI-ESSP
Ethiopian Economic Association
Conference
July 16, 2014
Addis Ababa
1

2. 2
Outline
• Introduction
• Objective
• Mapping procedure overview: approaches for soil
nutrient prediction
• Results found:
– Soil fertility status by nutrients, and
– Types of recommended fertilizers
• Further works

3. Background
Plants require many nutrients
(at least 12 types of nutrients)
S, Fe, Zn, and B
deficiencies can
limit the response
to NP(K)
Deficiencies must
be addressed
together
Nitrogen
Phosphorus
Potassium
Sulfur
Zinc
Magnesium
Calcium
Manganese
Yield
Boron

4. Background …

5. Countries with blending or
compound fertilizer plants in Africa
Fertilizer blending is a special type
of fertilizer mixing, where blends
are prepared by the mechanical
mixing of two or more granular
materials of fairly uniform size and
density in defined proportions. It
originated in the USA and now
dominates the fertilizer market in
many areas.
Often, a farmer has a bulk blend
prepared according to the soil test
report of the particular farm – a tailor-
made, ready-to-use mixture. The main
advantages to the farmers are:
• Nutrients are supplied in ratios to suit
the needs of particular soils and crops
• The cost per unit of plant nutrient is
generally low
• The cost of transportation and
spreading is low because of the high
analysis of bulk blends.
Whatisit?Whatareitsadvantages?
Mauritius
Legend:
Existing blending
plants and use
complex fertilizers
Guinea
Bissau
Niger
Chad Sudan
Tunisia
Algeria
Mali
Libya
Egypt
Mauritania
Morocco
Western
Sahara
Nigeria
Benin
Togo
Burkina
Ghana
Ivory
Coast
Guinea
Senegal
Liberia
Sierra Leone
Gambia
Ethiopia
Djibouti
Eritrea
Uganda Somalia
Kenya
Cameroon
C.A.Republic
Congo
Gabon
Equatorial
Guinea
Democratic
Rep. of Congo
Tanzania
Zambia
Angola
Mozambique
MadagascarZimbabwe
Botswana
Namibia
Swaziland
Lesotho
South
Africa
Malawi
Burundi
Rwanda
São Tomé e
Principe
S.Sudan
Comoros
No blending plants, but
consume compound
fertilizers
Seychelles
Many African countries have already developed fertilizer
blending plants; most use Compound fertilizers

6. EthioSIS workflow, products & services overview
Field
obser.
data
(CU)
NSTC
NATIONAL DATA CENTER BACKUP (PMO)
MAIN ETHIOSIS DATABASE (MOA)
Field
observ. data
Ethio.pts
Spect
data
Ethio.grids
Ethio.outputs
Lab data
(Labs across
Ethiopia)
WMS/portal
Africa
Grids
(AfSIS)
Raw Imagery
(NASA)
WC
data
Lab
Data
Tablets in
Field
Endusers’
computers
1
2
1
3
3
4
5
1
2 3
7
6
9
10
4
5
Legacy Data
Legacy Data
8
Today’s talk
Data flow
Processing activity
Processing intensity

7. • Historical soil information collection in Ethiopia has not been coordinated and
didn’t answer the question of status and lack of nutrients at the national level.
• Recommendation of specific fertilizers to increase yield to Ethiopian farmers was
not adequately based on knowledge about nutrient status of the agricultural
soils
• EthioSIS was launched to provide information on the status of soil fertility of the
agricultural lands
Introduction
• So far, EthioSIS has accomplished soil fertility survey in 240 woredas in the country.
• Of these, 35 are woredas in Tigray, thus making Tigray the first region where mapping has
been completed.
• By next year this time, the number of woredas for which soil fertility survey has been
completed will reach >500.
• By next year this time, Amhara and SNNPRS will also graduate while we only be left with
90 woredas in Oromia, and a few from the emerging Regions.
• So far 12 types of blended fertilizers are found to be deficient

8. Total by July 2015 = 501
woredas
Introduction

9. Objective
Specific objectives:
• map fertility status of macro and micronutrients for agricultural
areas,
• Identify deficient areas of each soil nutrient (macro & micro) by
administrative level.
• Produced soil fertility status of Ethiopia that enables the country to
revise its fertilizer advisory services
• Develop soil test based-fertilizer recommendations
General Objective:
develop digital soil mapping using geo-statistical approach

10. Methodology; data type & sources
Data types:
• Field data (geographic locations)
• Wet chemistry and spectral soil data
• Covariates (satellite images and other legacy
data)
• Land use data (agricultural land)
• Admin boundaries

11. Explanatory Variables (covariates)
used for soil nutrient prediction
• Climatic factors: Mean Annual Precipitation (MAP) and
Mean Annual Air Temperature (MAT), Land surface
temperature of the day and night (LSTd and LSTn);
• Reflectance: Blue, Red, NIR, MIR, BSAn, BSAs, BSAv,
WSAn, WSAs, WSAv;
• Topographic: Compound Topographic Index (CTI),
elevation, slope and relief; and
• Vegetation indices: EVI, fPAR, LAI, NDVI, NPP.

12. MODIS & Landsat reflectance &
vegetation products
MODIS energy balance (e.g, LST,
fPAR, albedo)
WorldClim & TRMM climatologies
(e.g, MAP Fournier Index & PET)
SRTM & ASTER terrain models
(e.g, elevation, CTI, slope, relief)
Examples of useful remote sensing covariates for digital soil
mapping & monitoring
available at:
ftp://africagrids.net

13. Methodology ---modeling approach
• Both Linear and non-linear models were
developed: kriging / RK with simulation model
• Using critical values for each soil nutrient
• 95% confidence interval
• Map resolutions of 1km grid size: we tested 250m for Tigray
• Predicted soil nutrients <- as a function of soil
nutrient results from lab and other relevant
covariates

14. Methodology --- Critical level concept
The critical level is the soil test level, below which a crop response to a nutrient
application may be expected given that no other nutrient is limiting

15. Some results

16. 16
First draft fertilizer recommendation suggests 54.7% coverage of NPSBZn & 30.3 % of NPSB

17. First draft fertilizer recommendation suggests 51.11% coverage of NPSBZn & 40.95 % of
NPKSBZn

18. First draft fertilizer recommendation suggests 68.59% coverage of NPSB & 9.40 % of NPS

19. Fertilizer recommendation map by woreda and
Fertilizer formulae
• Combined deficit areas of each nutrients
• Identify areas of proportions of each blend (combined
deficit nutrients)
 Fertilizer types are combined from deficit of
macro and micronutrients
• Fertilizer formulas developed by soil experts
• 12 types of blend fertilizers recommended for Ethiopian
soil (so far 6 types are unique for Tigray Region)
• These replace DAP, but Urea will be used as additional
top dressing fertilizer.

20. Fertilizer recommendation Types
Standard
Formula
No.
Fertilizer Type
Percent
coverage
for Tigray
Remarks
Standard
Formula Modified Blends for
Tigray soil
Percent
coverage
No.
for
Tigray
1 NPS
Not recommended for Tigray but for other
regions
2 NPSB 7.3
Also
recommend
ed for other
Regions
2 NPSB* 7.3
3 NPKSB 10.2 3 NPKSB* 10.2
4 NPSZnB 6.8
4 & 5
5
NPSZnB & NPKSZnB
NPKSZnB *
35.4
5 NPKSZnB 28.6
6, 7 &
127
NPSZn, NPKS & NPKSZn
NPKSZn* 3.7
6 NPSZn 1.5
8 & 10
10
NPSFeZn & NPKSFeZn
NPKSFeZn*
9.9
7 NPKSZn 1.5
So far,
recommend
ed for
Tigray
Region
9 NPSFeZnB* 3
8 NPSFeZn 8 11 NPKSFeZnB* 28.4
9 NPSFeZnB 3
* these are selected blend types discussed and agreed with
regional representatives for implementations on Tigray soil.
10 NPKSFeZn 1.9
11 NPKSFeZnB 28.4
12 NPKS 0.7

21. Suggested Formulae for blends
1. Formula 1 NPS: 19 N – 38 P2O5 +7S
2. Formula 2*NPSB: 18 N – 36 P2O5 + 7S + 0.71B  (95kg NPS + 4.9 kg Borax)
3. Formula 3*NPKSB: 13.7 N – 27.4 P2O5 – 14.4 K2O + 5.1S + 0.54B  (72.2Kg NPS + 24.1kg KCl + 3.7kg
Borax)
4. Formula 4 NPSZnB: 17 N – 34 P2O5 + 7S + 2.2Zn + 0.67B (89.9 kg NPS + 5.5 kg ZnSO4 + 4.6 Kg
Borax)
5. Formula 5*NPKSZnB: 13.0 N – 26.1 P2O5 – 13.7 K2O + 5.6S+ 1.72Zn + 0.51B (68.7kg NPS+22.9 kg
KCl + 4.9 kg ZnSO4+3.5 kg Borax)
6. Formula 6 NPSZn: 17.7 N – 35.3 P2O5 + 6.5S + 2.5 Zn  (92.86kg NPS + 7.14 kg ZnSO4)
7. Formula 7*NPKSZn: 15 N – 31 P2O5 – 8 K2O + 7 S+ 2.2 Zn  (81 Kg NPS + 13.5 Kg KCl + 5.5 Kg ZnSO4)
8. Formula 8 NPSFeZn: 17 N – 35 P2O5 +8 S+ 0.3 Fe+ 2.2Zn  (91.2 Kg NPS + 3.3 Kg Fe-chelate +5.5 Kg
ZnSO4)
9. Formula 9*NPSZnFeB: 17 N – 33 P2O5 + 7 S+ 2.2 Zn+ 0.3 Fe+ 0.5 B  (87.7 kg /100 kg NPS + 5.5kg/ha
ZnSO4 + 3.3 Fe-chelate +3.5 kg Borax)
10. Formula 10*NPKSFeZn: 15 N – 30 P2O5 – 8 K2O +7.0 S+ 0.3 Fe-chelate+ 2.2Zn  (77.7 Kg NPS + 13.5
Kg KCl + 3.3 Fe-chelate +5.5 Kg ZnSO4)
11. Formula 11*NPKSFeZnB: 17 N – 20 P2O5 – 8 K2O + 11 S+ 2.2 Zn+ 0.3 Fe + 0.5 B  (44.2 Kg DAP + 20
Kg Urea+ 13.5 Kg KCl +10 Kg Elemental S + 5.5 Kg ZnSO4 + 3.3 Fe-Chelate + 3.5 kg Borax)
12. Formula 12NPKS: 15 N – 29 P2O5 – 8 K2O + 10S  (56.5 Kg MAP + 20 Kg Urea+ 13.5 Kg KCl+ 10 Kg)
* These formulae are discussed and agreed with Tigray Region’s partners to be used for Tigray’s soil.

22. PROPOSED FERTILIZERS: Diga Woreda - Oromia
Formula 2: 18.1 N – 36.1 P2O5 – 0.0
K2O + 6.7S + 0.00Zn+ 0.71B  NPSB
(95kg/100kg NPS + 4.9 kg Borax)
Formula 4: 16.9 N – 33.8
P2O5 – 0.0 K2O + 7.3S +
2.23Zn+ 0.67B
 NPSBZn
(86 kg/100kg NPS + 6.4 kg/100kg
ZnSO4 + 4.6 Kg/100kg Borax)
Formula 5: 13.0 N –
26.1 P2O5 – 13.7 K2O
+5.6S+ 1.72Zn + 0.51B
 NPKSBZn
(68.7kg/100kgNPS+22.9kg/haKCl+4.9kg/
haZnSO4+3.56Borax)

23. The Ethiopian Soil Information System (EthioSIS) team will establish a web mapping portal similar to the one seen
below. The portal will allow stakeholders to view and download map data on a large range of soil properties
Data/Map Layers
Land Features
– Above surface vegetation
– Topography
– Land Use
– Erosion risk (wind and water)
Soil Physical properties
– Infiltration Capacity
– Texture
– Bulk Density
Soil Chemical Properties
– pH, EC, exchange acidity
– CaCO3 content (for high pH soils)
– Soil Organic Carbon
– Total nitrogen
– Available sulphur, phosphorus
– Exchangeable cations (K, Ca, Mg, Na)
– CEC
– micro-nutrients (Fe, Mn, Cu, Zn, B)
- Blend fertilizer maps and
recommendations
Eventual EthioSIS output
This list represents the current
EthioSIS aspirations; it can grow
this list to address a even wider
range of land information for
the specific sites of choice
Final web services

24. Demonstration (site trials) of new fertilizers

25. Initial observations from 2013 demonstrations: the
blended fertilizers are giving significant crop yield
increase as shown in the pictures below
Plot with DAP + Urea only.
Planting date 08/05/2013
Maize plot fertilized with
blended fertilizer (14 N-21
P2O5-15 K2O + 6.5 S+ 1.2
Zn + 0.5 B.)
Planting date 22/05/2013
• Location: SNNPR,
Region Soddo TVET
College
• Crop: Maize (Shone
variety)
• Fertilizer: Blended
fertilizer vs. DAP+Urea
• Planting: Blend plot
planted two weeks later
Blended fertilizer
demonstration
Maize on plot with blend
grew faster , greener, wider
leaves and thicker stems than
the one with DAP + Urea,
planted 2 weeks earlier
Source: Team analysis
This site is already visited by
more than 5,000 people

26. Blended fertilizer demonstration on farmer’s plot in East
Wollega, Guto Gida woreda, Demeksa kebele---October 8, 2013
The same tef variety Kuncho planted 15 days earlier
as broadcast and with DAP and Urea didn’t perform
well compared to the other adjacent plot
Teff variety Kuncho row-planted 15 days later
than the adjacent plot and that received blended
fertilizer 2 (NPSZn) showed good crop stand with
green color

27. Sample pages of Tigray Soil Fertility Atlas

28. Sample pages of Tigray Soil Fertility

30. Sample pages of Woreda Level Soil Fertility

31. Further works
• Using agricultural land as a base of prediction
• Refining the grid size 250 or 500m instead of 1k
• Ground level validation works by the research group are
necessary and should be continuous.
• About 500 woredas in all regions will be covered by the
end of 2015 so that the result will be refined as more
samples are included
• Local productions of blend fertilizers

32. Fertilizer blending plants
• Five fertilizer blends are to establish locally at four
major regions;
• Cooperative unions will operate these plants as a
business plant;
• One of the plant has been operated since 1 June 14
• 74,000 tons will be produced in 2014, and
• By 2017, Ethiopia will produce about 500,000 metric
tons of blend fertilizer.

33. The Fertilizer Blending initiative will make it possible for
Ethiopia to locally produce up to 400k tons of blends
396
367
172
500
0
300
600
2016 2018201720152014
20
Production (kton)
Tigray, Amhara, Oromia & SNNP
Production should start between
June 2014
Construction and equipment are
currently being procured
When
Where
Status
The Fertilizer Blending initiative
Capacity 100kton per plant (500k tons total)
Expected production of local plants (ktons)
Already for the first year, a production of
74kton of blended fertilizer is expected

34. One of the Blending Plant- Becho Woliso
by farmers’ cooperative unions

35. Innovations to help our country grow