Promoting sustainable land-use management: water, carbon and nutrient turnover
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Promoting sustainable land-use management:
water, carbon and nutrient turnover
Dirk Hölscher &
Pak Soekisman
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Objectives
• Present key results
• Draw conclusions for agricultural and forest
management
Tadulako University Palu
Bogor Agricultural University
Slide 2
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Land use types & land use gradients
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Aboveground biomass, premontane natural forests
Hertel et al. 2009
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Tree cover (%)
Steffan-Dewenter et al., 2007
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Meteorological flux tower in
a montane rainforest, Bariri
Tadulako University Palu
Bogor Agricultural University
Slide 6
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Measured net ecosystem exchange flux Fc,
extrapolated respiration flux RE, and
the sum of both fluxes Pg (gross photosynthesis)
8
Ecosystem Respiration 1760 g C m-2 year-1
RE
6
CO2 flux (g (C) m-2 d-1)
www.storma.de
4
2
0
Net turbulent uptake 970 g C m-2 year-1
-2
Fb
-4
-6
-8
Pg
Gross photosynthesis 2730 g C m-2 year-1
-10
OCT ' 03
JAN ' 04
APR
JUL
OCT
JAN ' 05
MAR
Ibrom et al., 2007
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
CO2 fluxes between the atmosphere: forest vs. cacao
Ibrom et al., 2007
Tadulako University Palu
Bogor Agricultural University
Slide 8
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Land use types and net ecosystem productivities:
scenarios
Olchev et al., 2008
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Land use types and net ecosystem productivities:
model results
Olchev et al., 2008
Tadulako University Palu
Bogor Agricultural University
Slide 10
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Fluxes of sensible (H) and latent (E) energy:
forest vs. cacao
Ibrom et al., 2007
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Sap flux of cacao and shade trees
Köhler et al. 2009
Tadulako University Palu
Bogor Agricultural University
Slide 12
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Cacao tree water use vs. canopy gap fraction
Shade trees enhanced water use
by cacao trees
(R2adj = 0.39, p = 0.043, n = 9)
Tadulako University Palu
Köhler et al. 2009
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Gumbasa river watershed
³
#
Catchment size:
c
1275 km²
/#
c
c
c
c
c
c
River discharge
c
³
#
c#³
³
#
³
#
c
R2 = 0.86
c
c
c
/# c
R²=0.83
0
³
#
/#
c
c
10
auto m atic s tage recorde r
automatic stage recorder
stage recorder - Fo restry departm ent
stage
recorder – Forestry
clim ate
station station
climate
climate
station
STORMA
clim ate station
- S TOR
M A project
20 Kilometers
main irriga tion channel
main irrigation chanel
re Li nd u National
Parc
LoreLoLindu
National
Park
PALU R IVER w atershed
Palu river watershed
Gerold & Leemhuis 2008
Gauging stations
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Modeling discharge of the river discharge, Gumbasa
watershed: effects of land cover change
Discharge (2003):
status quo 2003:
590 mm
land use scenario A1: 838 mm
+ 42%
1200m annual crops
Land use scenario A2: 724 mm
+ 23%
1200m change into cacao
16
discharge [mm d-1]
14
12
actual land use
land use scenario A1
land use scenario A2
10
8
6
4
2
3
01
/1
1/
0
3
01
/0
9/
0
3
01
/0
7/
0
3
01
/0
5/
0
3
3/
0
01
/0
01
/0
1/
0
3
0
Gerold & Leemhuis 2008
Tadulako University Palu
Bogor Agricultural University
Slide 15
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Modeled run off components
8
Direct flow
-1
Discharge (mm d )
7
Interflow
6
Base flow
5
4
3
2
1
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
2003
Kleinhans et al. 2004
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Nutrient balance of maize and agroforest
Dechert et al., 2004
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Summary
land use types & land use gradients
•
High carbon storage in forests of Sulwesi
•
High carbon uptake by forest
•
Shade trees enhance transpiration from agrofrests
•
River discharge change with land cover change suggested
•
Agroforestry strongly benefits from nitrogen input by N
fixing shade trees
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Implications
•
Very important to conserve remaining forests
•
Shade trees positively influence cacao cultivation
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Drought experiments
Premontane rainforest
Cacao/Gliricidia agroforest
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Cacao-Gliricidia agroforest
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
80% of plot area was covered by plastic panels (March 07- mid April 08);
n=3 roof (treatment) plots, n=3 control plots
M. Köhler
G Moser
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Soil water content
Tree sap flux
Cacao bean
yield
Tadulako University Palu
Litterfall
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Cacao bean dry mass (kg ha-1 2wk-1)
Cacao yield
Roof closure
120
Desiccation period Rewetting period
100
Control
80
-55%, p0.05
20
*
0
March
May
July
Sep
2007
Nov
Jan
March
May
2008
Moser et al. under review
Tadulako University Palu
Bogor Agricultural University
July
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Roof Cacao
to control ratio
1.2
1.0
0.8
0.6
0.0
-11%, p>0.05
Roof closure
Soil
storage
(mm)
Soilwater
water
storage
(mm)
Sap flux cacao
Soil water storage and cacao water use
600
500
400
Control
Mean±SD, n=3
Roof
300
- 40%, p < 0.05)
0
01Feb07
01Jun07
Tadulako University Palu
01Oct07
01Feb08
Bogor Agricultural University
01Jun08
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Complementary use of soil water
deuterium signal
Plant water
ACacao
B
Gliricidia
0.0- 0.1
Soil water (depth in m)
www.storma.de
0.1- 0.3
0.3- 0.5
0.5- 0.7
0.7- 1.0
Cacao
-70
Gliricidia
-60
-50
δ D (‰)
-40 -70
-60
-50
-40
δ D (‰)
Schwendenmann et al. 2009
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Water uptake depth cacao and Glricidia
Proportion of water uptake from a given soil depth interval (%)
0
Soil depth interval (cm)
www.storma.de
20
40
60
80
100
0-30
Cacao Jan 07
Gliricidia Jan 07
30-100
Schwendenmann, unpublished
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Root water potential
Cacao
Gliricidia
0
Control
Root water potential (bar)
Root water potential (bar)
0
-2
-4
-6
-8
-10
Roof
-12
-14
Cacao
R
C
Feb 07
-2
-4
-6
-8
-10
-12
-14
R
C
July 07
R
C
Aug 07
R
C
Sep 07
R
C
Mar 08
Gliricidia
R
C
R
C
R
C
R
C
R
C
Feb 07 Jul 07 Aug 07 Sep 07 Mar 08
Osmotic adjustment in cacao
Moser et al. under review
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
CO2 soil efflux
CO2 efflux (Mg C m-1 h-1)
Period of roof closure
Experiment period
Van Straaten, unpublished
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
CO2 efflux (Mg C m-1 h-1)
CO2 efflux response to soil moisture
(Adj R2 = 0.338, n = 94)
Van Straaten, unpublished
Volumetric water content (m3 m-3)
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Summary
cacao drought experiment
•
Cacao yield was little influenced for several months; a strong
(~50%) reduction was observed at the end of the experiment
•
Little response of tree water use to drought
•
Cacao and Glriricidia trees use soil water resources complementary
•
Small effects of drought on soil CO2 efflux
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Implications
•
Cacao is a suitable crop even where short dry spells occur
•
Shade trees: no negative effect on cacao tree performance
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Forest
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
0.7
vol. soil water content Pono ( )
Soil moisture
Throughfall displacement period
0.5
0.3
0.4
3
3
(m m )
0.6
Roof closure
10 cm
40cm control
40cm roof
40 cm
0.5
0.5
0.3
0.4
3
3
(m m )
0.6
0.7
0.3
0.4
3
3
(m m )
0.6
0.7
10cm control
10cm roof
150cm control
150cm roof
06/2007
03/2007
06/2007
150 cm
09/2007 12/2007
03/2008 06/2008
06/2008 09/2008
Tadulako University Palu
Köhler, unpublished
12/2008 03/20096/2009
06/2009
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Sap flux: all trees
Js Ratio roof over control
Complete dataset: roof plots devided by control plots
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0
25
50
75
100
125
150
175
200
225
250
275
300
325
Day of year 2008
Schuldt, unpublished
Tadulako University Palu
Bogor Agricultural University
350
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Stem wood production (2nd year)
Stem wood production (Mg ha-1 yr-1)
www.storma.de
10
8
6
4
2
0
Control
Tadulako University Palu
Roof
Moser, unpublished
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
CO2 soil efflux
CO2 efflux (Mg C m-1 h-1)
Period of roof closure
Experiment period
Van Straaten, unpublished
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
CO2 efflux (Mg C m-1 h-1)
CO2 soil efflux vs. soil moisture
(Adj R2 = 0.79, n = 93)
Van Straaten, unpublished
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Summary
forest drought experiment
•
Little response in tree sap flux to drought
•
Tree diameter growth was significantly reduced
•
Strong effect of drought on soil CO2 efflux
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Overall summary
• Old-growth forest is to be conserved
• Agroforestry is a promissing option in postforest landscapes
• Shade trees play a central role in cacao
cultivation
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Tadulako University Palu
Bogor Agricultural University
Slide 41
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Promoting sustainable land-use management:
water, carbon and nutrient turnover
Dirk Hölscher &
Pak Soekisman
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Objectives
• Present key results
• Draw conclusions for agricultural and forest
management
Tadulako University Palu
Bogor Agricultural University
Slide 2
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Land use types & land use gradients
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Aboveground biomass, premontane natural forests
Hertel et al. 2009
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Tree cover (%)
Steffan-Dewenter et al., 2007
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Meteorological flux tower in
a montane rainforest, Bariri
Tadulako University Palu
Bogor Agricultural University
Slide 6
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Measured net ecosystem exchange flux Fc,
extrapolated respiration flux RE, and
the sum of both fluxes Pg (gross photosynthesis)
8
Ecosystem Respiration 1760 g C m-2 year-1
RE
6
CO2 flux (g (C) m-2 d-1)
www.storma.de
4
2
0
Net turbulent uptake 970 g C m-2 year-1
-2
Fb
-4
-6
-8
Pg
Gross photosynthesis 2730 g C m-2 year-1
-10
OCT ' 03
JAN ' 04
APR
JUL
OCT
JAN ' 05
MAR
Ibrom et al., 2007
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
CO2 fluxes between the atmosphere: forest vs. cacao
Ibrom et al., 2007
Tadulako University Palu
Bogor Agricultural University
Slide 8
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Land use types and net ecosystem productivities:
scenarios
Olchev et al., 2008
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Land use types and net ecosystem productivities:
model results
Olchev et al., 2008
Tadulako University Palu
Bogor Agricultural University
Slide 10
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Fluxes of sensible (H) and latent (E) energy:
forest vs. cacao
Ibrom et al., 2007
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Sap flux of cacao and shade trees
Köhler et al. 2009
Tadulako University Palu
Bogor Agricultural University
Slide 12
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Cacao tree water use vs. canopy gap fraction
Shade trees enhanced water use
by cacao trees
(R2adj = 0.39, p = 0.043, n = 9)
Tadulako University Palu
Köhler et al. 2009
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Gumbasa river watershed
³
#
Catchment size:
c
1275 km²
/#
c
c
c
c
c
c
River discharge
c
³
#
c#³
³
#
³
#
c
R2 = 0.86
c
c
c
/# c
R²=0.83
0
³
#
/#
c
c
10
auto m atic s tage recorde r
automatic stage recorder
stage recorder - Fo restry departm ent
stage
recorder – Forestry
clim ate
station station
climate
climate
station
STORMA
clim ate station
- S TOR
M A project
20 Kilometers
main irriga tion channel
main irrigation chanel
re Li nd u National
Parc
LoreLoLindu
National
Park
PALU R IVER w atershed
Palu river watershed
Gerold & Leemhuis 2008
Gauging stations
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Modeling discharge of the river discharge, Gumbasa
watershed: effects of land cover change
Discharge (2003):
status quo 2003:
590 mm
land use scenario A1: 838 mm
+ 42%
1200m annual crops
Land use scenario A2: 724 mm
+ 23%
1200m change into cacao
16
discharge [mm d-1]
14
12
actual land use
land use scenario A1
land use scenario A2
10
8
6
4
2
3
01
/1
1/
0
3
01
/0
9/
0
3
01
/0
7/
0
3
01
/0
5/
0
3
3/
0
01
/0
01
/0
1/
0
3
0
Gerold & Leemhuis 2008
Tadulako University Palu
Bogor Agricultural University
Slide 15
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Modeled run off components
8
Direct flow
-1
Discharge (mm d )
7
Interflow
6
Base flow
5
4
3
2
1
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
2003
Kleinhans et al. 2004
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Nutrient balance of maize and agroforest
Dechert et al., 2004
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Summary
land use types & land use gradients
•
High carbon storage in forests of Sulwesi
•
High carbon uptake by forest
•
Shade trees enhance transpiration from agrofrests
•
River discharge change with land cover change suggested
•
Agroforestry strongly benefits from nitrogen input by N
fixing shade trees
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Implications
•
Very important to conserve remaining forests
•
Shade trees positively influence cacao cultivation
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Drought experiments
Premontane rainforest
Cacao/Gliricidia agroforest
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Cacao-Gliricidia agroforest
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
80% of plot area was covered by plastic panels (March 07- mid April 08);
n=3 roof (treatment) plots, n=3 control plots
M. Köhler
G Moser
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Soil water content
Tree sap flux
Cacao bean
yield
Tadulako University Palu
Litterfall
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Cacao bean dry mass (kg ha-1 2wk-1)
Cacao yield
Roof closure
120
Desiccation period Rewetting period
100
Control
80
-55%, p0.05
20
*
0
March
May
July
Sep
2007
Nov
Jan
March
May
2008
Moser et al. under review
Tadulako University Palu
Bogor Agricultural University
July
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Roof Cacao
to control ratio
1.2
1.0
0.8
0.6
0.0
-11%, p>0.05
Roof closure
Soil
storage
(mm)
Soilwater
water
storage
(mm)
Sap flux cacao
Soil water storage and cacao water use
600
500
400
Control
Mean±SD, n=3
Roof
300
- 40%, p < 0.05)
0
01Feb07
01Jun07
Tadulako University Palu
01Oct07
01Feb08
Bogor Agricultural University
01Jun08
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Complementary use of soil water
deuterium signal
Plant water
ACacao
B
Gliricidia
0.0- 0.1
Soil water (depth in m)
www.storma.de
0.1- 0.3
0.3- 0.5
0.5- 0.7
0.7- 1.0
Cacao
-70
Gliricidia
-60
-50
δ D (‰)
-40 -70
-60
-50
-40
δ D (‰)
Schwendenmann et al. 2009
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Water uptake depth cacao and Glricidia
Proportion of water uptake from a given soil depth interval (%)
0
Soil depth interval (cm)
www.storma.de
20
40
60
80
100
0-30
Cacao Jan 07
Gliricidia Jan 07
30-100
Schwendenmann, unpublished
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Root water potential
Cacao
Gliricidia
0
Control
Root water potential (bar)
Root water potential (bar)
0
-2
-4
-6
-8
-10
Roof
-12
-14
Cacao
R
C
Feb 07
-2
-4
-6
-8
-10
-12
-14
R
C
July 07
R
C
Aug 07
R
C
Sep 07
R
C
Mar 08
Gliricidia
R
C
R
C
R
C
R
C
R
C
Feb 07 Jul 07 Aug 07 Sep 07 Mar 08
Osmotic adjustment in cacao
Moser et al. under review
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
CO2 soil efflux
CO2 efflux (Mg C m-1 h-1)
Period of roof closure
Experiment period
Van Straaten, unpublished
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
CO2 efflux (Mg C m-1 h-1)
CO2 efflux response to soil moisture
(Adj R2 = 0.338, n = 94)
Van Straaten, unpublished
Volumetric water content (m3 m-3)
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Summary
cacao drought experiment
•
Cacao yield was little influenced for several months; a strong
(~50%) reduction was observed at the end of the experiment
•
Little response of tree water use to drought
•
Cacao and Glriricidia trees use soil water resources complementary
•
Small effects of drought on soil CO2 efflux
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
Implications
•
Cacao is a suitable crop even where short dry spells occur
•
Shade trees: no negative effect on cacao tree performance
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Forest
Tadulako University Palu
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
0.7
vol. soil water content Pono ( )
Soil moisture
Throughfall displacement period
0.5
0.3
0.4
3
3
(m m )
0.6
Roof closure
10 cm
40cm control
40cm roof
40 cm
0.5
0.5
0.3
0.4
3
3
(m m )
0.6
0.7
0.3
0.4
3
3
(m m )
0.6
0.7
10cm control
10cm roof
150cm control
150cm roof
06/2007
03/2007
06/2007
150 cm
09/2007 12/2007
03/2008 06/2008
06/2008 09/2008
Tadulako University Palu
Köhler, unpublished
12/2008 03/20096/2009
06/2009
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Sap flux: all trees
Js Ratio roof over control
Complete dataset: roof plots devided by control plots
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0
25
50
75
100
125
150
175
200
225
250
275
300
325
Day of year 2008
Schuldt, unpublished
Tadulako University Palu
Bogor Agricultural University
350
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Stem wood production (2nd year)
Stem wood production (Mg ha-1 yr-1)
www.storma.de
10
8
6
4
2
0
Control
Tadulako University Palu
Roof
Moser, unpublished
Bogor Agricultural University
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
www.storma.de
CO2 soil efflux
CO2 efflux (Mg C m-1 h-1)
Period of roof closure
Experiment period
Van Straaten, unpublished
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
CO2 efflux (Mg C m-1 h-1)
CO2 soil efflux vs. soil moisture
(Adj R2 = 0.79, n = 93)
Van Straaten, unpublished
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Summary
forest drought experiment
•
Little response in tree sap flux to drought
•
Tree diameter growth was significantly reduced
•
Strong effect of drought on soil CO2 efflux
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Overall summary
• Old-growth forest is to be conserved
• Agroforestry is a promissing option in postforest landscapes
• Shade trees play a central role in cacao
cultivation
Tadulako University Palu
Bogor Agricultural University
www.storma.de
SFB 552 “STORMA” – Stability of Rainforest Margins in Indonesia
Tadulako University Palu
Bogor Agricultural University
Slide 41