Understanding existing spatial variability diagnostics at regional scale

Understanding existing spatial variability
diagnostics at regional scale

International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org

70
60
Yield t ha -1 cycle -1

50
40
30
20
10
0
Uganda Rwanda Burundi North Kivu South Kivu

Sites (n) 9 5 5 4 4
Farms (n) 84 128 147 120 120
Cycle = the period between subsequent harvests from a single mat. This value is around 1 year at 1200 m.a.s.l. but increases with altitude
Sites = nr. of districts (Uganda) or villages (Rwanda, Burundi, North Kivu, South Kivu)
The top and bottom of the error bars represent the maximum and minimum site average yield per region/country

from Lake Victoria basin to Albertine rift

East Rwanda
Rusizi
East Burundi Kivu
Semliki
SW Uganda Region
Central Uganda 25 t/ha/cycle 45 t/ha/cycle
15 t/ha/cycle
1600-
2100m
1100m 1300-1400m

Rainfall

Pest and disease pressure

Soil fertility

Plant densities


5.0

 Drought major constraint <1200 mm/yr 4.5
 Soil fertility highly variable, but generally
better near Albertine rift 4.0

 High foliar K conc = high productive sites
3.5
 Pest pressure low > 1300m
 BBTV and BXW ‘restricted’ to hotspots 3.0

K (% of dry matter)
Conclusion: abiotic stresses very important 2.5

2.0

Cy oke
1.5

Ka ga-2

R
G an
G ga-1u
Ci ale

Ki
Ki

N
Bu

Lu i
Ki ung

M ala
Lu nd

uh
Kbam
an
ite g
Bi

ite

ru
bo

b

ze
bu o

un
al b

rh
rh
ng

hi o-

an
t

ng
iva a

ye

ol
h
o

go
a
i

Yield gap analysis in Uganda


diagnostics at village scale
Poor Medium Rich
‘Poor’ versus ‘Rich’ farmers: Number of farms 17 28 5

• Yields Banana performance
Bunch weight 16.2b 16.4b 20.1a
• Arable land
Average spacing (m) 2.2 2.3 2.2
• Hired labor
Land, livestock, and labor
• Livestock
Tot. arable land (ha) 0.32b* 0.48b 0.55a
• External revenues % land und. banana 70 70 70
• Commercialization Hired labor (man/day) 0.5b 0.8b 3.2a

Cows (nr) 0.77 2.2 3.0
Conclusion: Soil Org Carbon (%) 1.3 1.3 1.4
Large differences in access Weevil damage (XT %) 4.0 5.4 4.4
to resources → technology Income sources
choice Earning salary % 0b 4b 40a
Ext. financial sup. % 24b 50ab 80a
PhD thesis ongoing on farmer
% farms selling ban. 47b 75a 100a
innovation in GL region
*Letters behind numbers in the same row indicate significant differences (p<0.1)


diagnostics at farm scale

Delstanche, van Asten, Gaidashova, Delvaux – Eurosoil conference
MSc thesis I.A. Newton
Most still needs to be published

Understanding existing temporal variability
on-farm monitoring study in SW Uganda
150 plants - 10 farms - 2 years
• Peak production May – Oct
→ prices are low
• Low production Nov – Feb
→ prices are high
Sucker emergence → Harvest date
• Give preference to suckers
emerged in Q1 over those that
emerged in Q4
• Farmers prefer desuckering in
Dec-Jan, but they should then
leave the smallest, not the biggest
suckers

Got Matooke for Christmas →
Birabwa, van Asten, Newton, Taulya,
Mombasa presentation – to submit to Act Hort


Understanding existing cropping systems
Comparing banana-coffee mono and intercrop

APEP-funded project
300 farmer fields in Uganda

• Bananas do not reduce (<13%)
coffee yields, but Robusta
banana yields
• Banana intercrop generates
+ 700 $/ha/yr in Robusta
+ 1900 $/ha/yr in Arabica

PhD research on banana-coffee
systems has started in Burundi
under CIALCA-II

van Asten, Mukasa, Uringi
poster Mombasa – Act Hort, to be submitted
R4D review feature story


Cycle 1
Cycle 2
Cycle 3

Pushing system components to their boundaries A 90
A
75
2005 - 1034mm
2006 - 1334mm
2007 - 1633mm

Drought trials 60

45

30

15

Pot trials 0
Sept 2004 Mar 2005 Sept 2005 Mar 2006 Sept 2006 Mar 2007 Sept 2007

Rainfall (mm)
a. Four cultivars (AAA-EA, AAA, ABB, AB) Cycle 1

Cycle 2

b. Three moisture treatments B 90
2005 - 1206mm
75

pF 1.8 – 2.1
2006 - 1380mm

no stress: 60
2007 - 935mm

45
moderate stress: pF 2.5 – 2.7 30

pF 2.8 – 2.9
15
strong stress: 0
Dec 2004 June 2005 Dec 2005 June 2006 Dec 2006 June 2007 Dec 2007

c. Measure stress (e.g. stomatal conductance) C Saturation (pF 0) Field capacity (pF 2) Wilting point (pF 4.2) 0-30 cm 30-60 cm 60-90 cm

0.45
c. Determine water use efficiency
0.35

d. Use findings to validate field results

Volumetric moisture content (m 3 m-3)
0.25

0.15

Interim results: bananas don't look stressed 0.05
April 2005 Nov 2005 June 2006 Dec 2006 July 2007
when they actually are! D Saturation (pF 0) Field capacity (pF 2) Wilting point (pF 4.2) 0-30 cm 30-60 cm 60-90 cm

0.45

Planning field trial in CIALCA-II project 0.35

0.25
Results from the above not published thus far
0.15
Field trial results - Nyombi et al (PhD reseach) in 2009
0.05
June 2005 Jan 2006 Aug 2006 Feb 2007 Sept 2007


Testing the hypotheses in the field
Nutrient omission trials
8000
1. Setup

Banana finger biomass (kg ha -1)
a. Central and Southwest Uganda
b. N, P, K, Mg, Zn, S, B, Mo 6000

c. Target yield 50 t/ha/yr
4000
2. Preliminary findings after 2-3 cycles
a. K is most deficient
2000
b. Fertilized yields poor (< 30 t/ha/yr) 0N-0P-0K 0N-50P-600K
150N-50P-600K 400N-0P-600K
c. Drought stress is a major problem 400N-50P-0K
400N-50P-600K
400N-50P-250K
Max dillution
Max concentration
d. Ferralsols soils → poor root systems 0
0 200 400 600 800
e. Fertilizer improves sensory quality K uptake (kg ha-1)

0
6.0 FULL
5.5
Rooting depth (cm)

5.0

4.5

4.0
-50
3.5

3.0

2.5

2.0

1.5
-100
1.0

0.5

0.0
-150 -100 -50 0 50 100 150
Horizontal distance from center of pseudostem -K
(cm)

Nyombi, van Asten, et al.: Draft ready → submit Feb 2009
Taulya, van Asten, et al: Global plant sci book - submittedAgriculture – Institut international d’agriculture tropicale – www.iita.org
International Institute of Tropical

Optimal mulch thickness
On-station trial at ISAR, Rwanda

1. 0 cm mulch
2. 5 cm mulch
3. 10 cm mulch
4. 20 cm mulch
With and without shading
30

Soil Moisture Conten (Vol %)
Soil moisture monitoring
→ 5 cm already very effective
20 Mulch rates

Soil chemical properties 0 cm
1.00

→ improvement proportional to application 10 5 cm
2.00

10 cm
3.00
Van Asten, Twagirayezu, Gaidashova
0 20 cm
4.00
Rwanda Agricultural Conference 1 2 3 5 6 7 8 9 10 11 12
Presentation and paper, 2007. Week Number (1 = 9 Sept)


Mulch and zero-tillage trials
Setup in CIALCA project
8 researcher-managed trials
in Rwanda, Burundi, and DRC

1. Mulch removal + tillage
2. Self-mulch + no-till
3. Trypsacum + no-till
4. Hyparrhenia + no-till
All intercropped with bush beans

Objectives
• Impact on nutrient stocks and flows
PhD thesis Syldie Bizimana (ISABU - Burundi)

• Impact on soil physics and root systems
PhD thesis Tony Muliele (INERA - DR Congo)
• Impact on banana + bean crop performance
MSc thesis Agnes Mukdandida (ISAR- Rwanda)


other field and lab trials

Planting density trials in Rwanda
• from 1000 – 5000 plants/ha
• 3 different cultivars
• 3 contrasting agro-ecologies
• compare with farmer practices
PhD thesis Telesphore Ndabamenye (ISAR-Rwanda)
CIALCA-Bioversity sponsored

Abuscular Mychorrizal Fungi (AMF)
• On-farm diagnostics and pot trials Rwanda
• Diagnostics and field trial in Kenya, Uganda
Mulch x Nematode trial in Rwanda
• Establish yield loss due to P. Goodeyi
PhD thesis Svetlana Gaidashova (ISAR-Rwanda)
Collaboration in Kenya with TSBF
AMF research presented in Mombasa conference
Paper on AMF on-farm diagnostics to be submitted


Crop growth and nutrient response models
Ugandan potential yield – 112 t/ha/yr

Crop growth model based on:
A
1. Light interception and L.U.E.
2. Temperature sum and biomass partitioning
3. Water limited yield
4. Nutrient (N, P, K) limited yield (QUEFTS)
PhD research of Kenneth Nyombi (Wageningen University)
+

B = C DTR
dDLAI/dt

LAI
DAvtmp

RAIN
PARINT
dGLAI/dt
EVAPO
RNINTC KDF

TRANRF
SLA
WATER
RN

PTRAN W lv, g W lv,d
TRAN Tsum
EXPLOR (dW/dt) lv,d
(dW/dt) lv dTsum/dt
dW/dt
W st
(dW/dt) st
LUE Tbase
DRAIN W rt W rt,d
(dW/dt) rt,d
(dW/dt) rt
W co

(dW/dt) co

W su
(dW/dt) su

W bu
(dW/dt) bu


On-farm testing of best-bet technologies
the APEP project

APEP demo plots Uganda matooke farm gate bunch price

• application of blanket NPK fertilizer 300

• 94 demos versus 84 control

Bunch price (USH/kg)
• Demos yield 25 – 100% 200

• MRR > 500% close to Kampala
100
• MRR < 100% beyond Masaka
0
Conclusion: 0 50 100 150 200 250 300 350
Distance to Kam pala
Fertilizer only profitable near Kampala
New fertilizer recommendations
Banana and Coffee taking into account
• nutrient deficiencies (= region)
• target yield (= resource availability)
Van Asten et al., APEP final technical report
Wairegi, van Asten, et al. AFNET conference paper
Van Asten et al., Mombasa presentation, Act Hort


Projected banana-coffee work

Capacity development
Output 4 Partnerships & training materials
Capacity &
Scientific synergies synergies

Output 1 Output 2 Output 3
Crop physiology Agronomy Socio-economics
Effect of banana shade under Identify and test improved soil Strengthen coffee-value chain
different levels of water and and water management through:
nutrient stress on: technologies Determinants for investments
Coffee yield (quantity, quality) Identify drivers of productivity Access to input markets
Photosynthetic capacity Map nutrient deficiencies Output markets (niches)
Pest & disease pressure Participatory testing Organisational structures
Trade-off analysis Cost-benefit analysis

Plant arrangement Improved soil and Empowerment of
Strengthening
recommendations water practices coffee-value chain
coffee actors

organ plant field farm farm organisation market

IITA
NARO
AIT IFPRI

Figure 2: Relational diagram showing the relationship between the research conducted
for the four outputs, the spatial level that the research activities primarily target, and the
technical backstopping domains of the project research partners.

Understanding existing spatial variability diagnostics at regional scale

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Understanding existing spatial variability diagnostics at regional scale