1. SHADE TREE SPECIES COMPOSITION AFFECT WATER
DYNAMICS IN COFFEE AGRO-FORESTRY SYSTEMS OF THE
WESTERN GHATS. INDIA.
Vaast P1.3. Charbonnier F1. Guillemot J1. Maruti G2 & Devakumar AS2
1.CIRAD. Montpellier. France. 2UAS Bangalore. College of Forestry.
Ponnampet. Karnataka. India. 3ICRAF Nairobi. Kenya.
This study is part of the CAFNET Project: Connecting. enhancing and sustaining environmental
services and market values of coffee agroforestry in Central America. East Africa and India
Financed by European Commission
Program on Environment in Developing Countries

2. Context
•
•
India 5th largest world coffee producer (70%
Robusta)
Production concentrated in the Western Ghats
– One of the world hotspots of biodiversity
•
Climate characterized by South West Monsoon &
Long dry period (5 months)
•
Traditionally, coffee grown under multistrata
native shade trees (>50 spp /Ha)
•
Rapid expansion of coffee over last 30 years
•
Since the 80s, changes in coffee management =>
tree tenure, volatility of coffee price
(diversification: pepper/timber)=> exotic trees (i.e.
Grevillea robusta) replacing native species.
•
Water is one key ecosystems service identified by
stakeholders
1977
1997
2007

3. Study sites
• 6 sites (3 presented here)
• Western Site: Bettageri 3 500 mm yr-1
• Central Site: Pachat 2 000 mm yr-1
• Eastern site: Nanjarayapatna 1000 mm
• For each site. two 1 000 m² plots:
– shaded trees predominantly exotic (Grevillea
robusta >80%)
– shaded trees predominantly native species
(>80%)
Nanjarayapatna
•
Chettimany
Bettageri
Chettaly
Hoddur
Pachat
•
Plots of a same site nearest possible from each
other;
The bio-physical characteristics of plots the
most similar possible to only compare the
impact of shade composition on hydrological
fluxes.

4. Material & Methods
• Characteristics of coffee and trees (LAI, BA..)
• Hourly meteorological data (ETP)
• Daily sap flow monitoring
– Granier probe => Trees
– Dynamax probe => Coffee
• Daily rain interception (trees & coffee canopy)
• Stemflow (coffee & trees)
• Soil water content down to 1.6 m (Diviner 2000)
• Runoff

5. Water fluxes
GR = I + (Se) + T + R + ΔS + Drainage
Transpiration
Gross
Rainfall
Shade tree
Interception
Interception
Soil evaporation
Coffee
Runoff
Soil water stock
Drainage

6. Coffee
Shade trees
N
Western Site
Exotic
Native
LAImax*
LAImin*
N
LAImax*
1120
1420
2.3 (0.5)
2.6 (0.7)
1.5 (0.4)
1.3 (0.4)
1210
650
1.4 (0.3)
1.0 (0.4)
2210
1360
2 .0 (0.9)
2.4 (0.9)
1.5 (0.7)
1.7 (0.6)
500
480
1.7 (0.3)
0.9 (0.3)
1120
1560
3 (0.7)
2.6 (0.6)
2.1 (0.5)
1.8 (0.4)
430
150
0.9 (0.1)
1.0 (0.5)
CentralSite
Exotic
Native
Eastern Site
Exotic
Native
Coffee Density per ha (N). Basal area in m²/ha (BA).
Leaf area index at the end of the monsoon (LAImax).
Leaf area index at the end of the dry season (LAImin)
Standard deviation betwween parenthesis
Images taken from canopy analyzer CI 110. CID
Heterogenous canopy.
typical plurispecific.
native plot
Homogenous canopy. typical
of monospecific. exotic.
Grevillea robusta plot
Robusta coffee canopy

7. Transpiration
Tree
Interception
Soil evaporation
Coffee
Gross
Rainfall
Runoff
Soil water stock
Drainage
Gross throughfall Coffee Tree
SF
SF
Rainfall
mm
Western
Site
Exotic
Center
Site
Exotic
Eastern
Site
Exotic
Run-Off
Tree (%) System (%)
%
Native
930
%
%
71
0.3
5.0
3
25
4.0
0.3
2.9
4
20
5.0
78
0.4
2.9
5
18
5.2
85
2 040
%
78
3 368
Native
Native
Interception
0.5
2.0
6
15
5.7
78
0.7
0.6
1
22
3.8
81
1.3
1.0
4
19
3.4
Gross Rainfall (Gross RF) measured from June to October. Throughfall as direct rain reaching the soil. Coffee stem flow (Coffee SF). Tree
stem flow (Tree SF). and Interception expressed in percentage of the Gross rainfall

9. Estimated drainage from Total rainfall. net rain infiltration into the soil and
total system transpiration (coffee + tree) in native and exotic plots of the three
sites (Eastern. Central and Western) of the Kavery watershed.
Total
System
Estimated
Infiltration
Transp.
Transp.
(mm)
(mm)
(mm)
(mm)
(mm)
3 529
1 610
287
484
771
838
1 925
581
777
1 357
567
1 499
267
541
718
781
1 630
492
658
1149
480
537
118
200
318
219
601
217
290
508
93
Transpiration Drainage
Plot
Exotic
Tree
(mm)
Western
Coffee
Rainfall
Site
Net rain
Native
Central
Exotic
2 012
Native
Eastern
Exotic
Native
1 024

10. Conclusion
• Coffee canopy intercepts largest part (9-21%) of rainfall
(shade tree composition not important)
• Coffee under native trees transpires more than under
exotic ones
• Native trees transpire more than exotics (dry season),
but exotics dry out more topsoil
• Runoff comparable in exotic and native plots (3-6%)
• Rain infiltration higher in native than exotic
• Drainage below root zone lower in native than exotic
•  less water recharging aquifers/rivers in
native than exotic plots