Nutrient Cycling in Amazonia:
environmental and climatic changes
www.inpa.gov.br/lba
Flávio J. Luizão (and LBA collaborators)
National Institute for Amazonian Research – INPA
Central Office LBA Program – Biogeochemcial Cycles
Forest and Rivers: very closed linked and both very important for the
atmospheric processes and the functioning of terrestrial ecosystems in Amazon
BIOGEOCHEMICAL TRANSFORMATIONS of C, N and P
Photosynthesis
Respiration
“Aloctone”
processes
POC
Decomposition
Leaching
“Autoctone”
processes
DOC
Primary production
Respiration
Cycling
DOC = Compostos solúveis, como
carbohidratos e amino-ácidos e
macromoléculas mais refratárias,
como ácidos fúlvicos e húmicos
Na maioria dos pequenos rios, o balanço de carbono é dominado pelos materiais
alóctones, que provém das áreas terrestres adjacentes, como as folhas que caem
diretamente sobre a água e são trituradas e decompostas durante o transporte.
Em outros casos, o aporte alóctone é dominado por carbono orgânico dissolvido
(DOC) proveniente da decomposição e lixiviação da matéria orgânica nos solos.
Caxiuana, Brazil
Pristine (primary) forest = highly diversified and productive, despite of
lack of soil mineral nutrients  complex and varied mechanisms of O.M.
and nutrient economy, and efficient recycling of organic residues
Nutrient content of soils
Rio Grande do Sul
Amazon Region
Nutrient contents
Oxisols:
Low cation exchange capacity (CTC)
Low water holding capacity
Good soil aggregation and structure
Nutrient conservation mechanisms:
- Relatively large root biomass
- Roots concentrated close to soil surface
- Simbiotic association roots-fungi (mycorrhizae)
- Plant/root tolerance to soil acidity
Organic Matter recycling
• FLORESTAS NATIVAS
DENSA CAMADA DE
LITEIRA
(Folhas, Material
reprodutivo, Material
Lenhoso e Fragmentos
Finos)
(Vieira,1988)
Fonte: Costa, 2002
Liteira representa um dos principais mecanismos de
reciclagem e distribuição de nutrientes na maioria dos
ecossistemas terrestres
(Vitousek & Sanford, 1986; Hughes & Fahey, 1994)
Litter –
major source of nutrients and soil cover
Annual nutrient input through
fine litterfall in plateau forest in
central Amazon
Nutrients
Carbon
Nitrogen
Calcium
Potassium
Magnesium
Phosphorus
Luizão, 1989
Annual input per hectare
4t
151 kg
37 kg
15 kg
14 kg
3 kg
Litter layer on soil surface
Litter protecting soil surface (Maracá)
Soil loss per ha
Canopy + litter
0.51 kg/m2
Canopy removed
1.03 kg/m2
Litter also removed 9.38 kg/m2
(Ross, 1990)
Roots
Macrobiota – soil engineers
Earthworms & soil structure
Forest  pasture (1 year)
500 µm
Pasture  forest (1 year)
Barros et al., 2001
Microbiota – OM decomposers
Marasmoid Fungi
Mycorrhizal Fungi
Root-Fungi association (Mycorrhizal roots/fungi)
seringueira
angelim
cacaueiro
açaizeiro
embaúba
cupuaçuzeiro
OCORRÊNCIA
NA AMAZÔNIA
guaranazeiro
cumarú
lacre
pupunheira
cedro
andiroba
(Bonetti et al., 1984; Bonetti & Narraro, 1990; Guitton, 1996; Luizão et al.,
1997; Oliveira et al., 1999; Rodrigues, 2002; Ordinolla, 2003)
 List (131 regional species associated to FMA)
5
Importance of soil mycorrhiza in the tropics
Coarse Litter (CWD)
Woody Material with diameter > 2 cm
High concentration of C and low for nutrients
Few studies in tropical forests
Stock in untouched forest : 30-40 Mg.ha-1
CWD must be included in estimates of C fluxes /
forest respiration ....
.....as well as for nutrients, because of relatively high
nutrient concentrations in the diameter class 2-10 cm
(Pauletto, 2006)
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
n = 95
O
Sp
ld
od
ox
os
is
ol
ol
/p
s
sa
m
m
en
t
U
Yo
lti
so
un
ls
ge
ro
C
xi
ry
so
st
al
ls
lin
H
e
ol
sh
oc
ie
en
ld
e
al
lu
viu
O
ld
m
er
in
al
ce
lu
pt
vi
is
um
ol
s/
an
di
so
ls
Biomass carbon increment
(t C/ha/yr)
RAINFOR (multiple plots): Forests appear to be
increasing biomass at a rate linked to soil fertility
Increasing soil Fertility
Local topography
•
Área hidrológica (6,8 km2)
Platô
Vertente
Baixio
Fonte: (LBA, 2003)
Monthly nutrient input through leaf-litter
along a topographic gradient in the forest
Entrada mensal de nutrientes
Platô
Vertente
Baixio
Q u a n t id a d e s /m ê s
( Kg /h a )
18,0
15,0
12,0
9,0
6,0
3,0
0,0
N
K
Ca
Nutrientes
Mg
Nutrient stock in the leaf-litter on the
forest floor topographic gradient
3,00
2,50
2,00
(g /k g)
Co n ce n tr ação d e n u tr ie n te s
FOL HA S
1,50
1,00
0,50
0,00
P
K+
Ca++
Nu tr ie n te s
P LA T Ô
VE R T E N T E
B A IXIO
Mg++
Entrada mensal de nutrientes
Vertente
Baixio
N it r o g ê n io ( g /K g )
Platô
Concentração de nitrogênio nas folhas
das árvores
Q u a n t id a d e s /m ê s
( Kg /h a )
18,0
15,0
12,0
9,0
6,0
3,0
30
20
10
0
Platô
0,0
N
K
Ca
Vertente
Baixio
Toposseqüência
Mg
Nutrientes
Paiva, 2005
Monteiro, 2005
Net mineralization
Nitrate ions
40
40
30
30
20
20
10
10
0
-10
0
plateau
slope
bottom
Luizão et
al., 2004
-10
plateau
slope bottom
Latossolo
4,0
100,0
3,5
3,0
2,5
60,0
2,0
40,0
1,5
1,0
20,0
Carbono (%)
Argila (%)
80,0
Relationship between soil
texture and soil carbon along
the profile in plateau (Oxisol)
and valley (Spodosol) under
primary forest – ZF2
7
Espodossolo
0,5
0,0
6
0,0
10-45
45-82
82-108
108-200
Profundidade (cm)
Teor de argila
Teor de carbono
5
(%)
0-10
Teor de argila
4
Teor de carbono
3
2
Soil C stocks (0 – 2 m)
1
0
Plateau = 187 +- 28,5 Mg.ha-1
Slope = 171 +- 71,2 Mg.ha-1
Valley = 241 +- 23,8 Mg.ha-1 (66 %
in 0-30 cm soil layer)
0-25
25-59
Profundidade
(cm)
59-120
100%
Frações de COS
80%
60%
Soil Organic Matter
Fractionation
C-Silte
C-Argila
C-Areia
40%
C-FLI
C-FLL
20%
Valley (Spodosol)
100%
0%
0-5
5-10
10-20
20-40
40-60
60-80
80-100 100-160 160-200
Camadas do solo (cm)
Plateau (Oxisol)
Slope (Ultisol)
100%
Frações de CO S
80%
C-Silte
60%
C-Argila
C-Areia
C-FLI
40%
C-FLL
20%
80%
C-Silte
Frações de COS
C-Argila
C-Areia
60%
C-FLI
C-FLL
0%
0-5
5-10
10-20
20-40
40-60
60-80
80-100
Camadas do solo (cm)
40%
20%
0%
0-5
5-10
10-20
20-40
40-60
60-80
80-100 100-160 160-200
Cam adas do solo (cm)
Fraction LL (light and free):
plateau = 0.1 a 26 g.kg-1
slope = 0 a 38
valley = 0.9 a 43
C transport to the forest streams
• DELINEAMENTO EXPERIMENTAL
LITEIRA DO IGARAPÉ
Folhas inteiras (L)
TRIAGEM
Quebradas ou fermentadas (F)
Material lenhoso (W)
ANÁLISE QUÍMICA: C E NUTRIENTES
FONTE: Costa, 2004
Environmental Changes in Amazonia
Deforestation in Amazonia 1977-2007 in km² per year
Desflorestation (km² per year)
35000
Is it sustainable?
30000
25000
20000
15000
10000
5000
* average for the decade
INPE data, 2007
06/07
05/06
04/05
03/04
02/03
01/02
00/01
99/00
98/99
97/98
96/97
95/96
94/95
92/94
91/92
90/91
89/90
88/89
77/88*
0
Selective logging
BIONTE Project ZF-2, Manaus)
34,3 m3 timber extracted per ha (6-10 trees, DAP > 55 cm
% clearings: 32 % % area tractor tracks: 11,7 %
Nutrient Exported in logs: 65,3 kg N; 0.86 kg P; 18,8 kg Ca
Partly exposed soil:
Lower decomposition rates;
Nutrient losses through soil percolation (first weeks);
Patches in the clearings with plant debris (branches & canopies):
Higher soil moisture  high decomposition rates;
Higher concentration of available nutrients in soil (Ca, Mg) after 1,5
years  higher relative density and growth of climax species
Density: pioneer/climax: 0.96 (open area) and 1.54 area with debris
Pereira et al. (2002) Forest Ecology and Management)
Forest fragmentation at ZF3 – PDBFF
Photo: R. Bierregard
Forest fragmentation increase stocks of fine
litter on soil surface ....
13
B iom ass (M g/ha)
12
Y = 9.46 - 0.67 log X
R=0.28, P<0.05
11
10
9
8
7
6
5
100
1000
Distance to edge (m)
Nascimento & Laurance (2004)
Ecological Applications
CW D production (M g/ha/year)
... and CWD as well
12
Y = 10.87 - 2.30 log X
R=0.60, P<0.0001
10
8
6
4
2
0
100
1000
Distance to edge (m)
Nascimento & Laurance (2004)
Ecological Applications.
LITTER production in fragmented forest
Edge X Interior (3-year períod):
At edges, litterfall was 0.68 t/ha/yr higher than
at forest interior
(9.50 +- 0.23 vs. 8.82 +- 0.14)
Leaf litter Ca concentration > near the edges 
soil Ca mobilization by pioneer species at the
edges
Vasconcelos & Luizão (2004) Ecological Applications
Converting a highly diversified forest…. into a pasture
planted with just one (generally exotic) grass species….
Strong impacts expected, because:
Nutrient losses from biomass burning
(mainly N, S, K)
No litter cover of soil surface
No litter nutrient inputs
Guidelines for optimizing soil biota and
organic matter recycling:
Keeping soil surface always covered X
 Adding green manures to soil surface X
 Selecting plant species which produces
biomass with high nutritional quality X
X
 Keeping soil and plant biodiversity

Thus: soil conditions deteriorate quickly!
N2O Fluxes in Forest x Burnt area x Young
Pasture on Oxisol > 70% clay in Manaus (Luizao
et al. 1989):
Annual Flux of N2O increased 3x in pasture:
Forest & Burnt: 1,9 kg ha-1 yr-1
Young Pasture: 5,7 kg ha-1 yr-1
Dry season: forest and pasture similar
Wet season: fluxes 3-5x higher in pasture
(> 10 ng cm-2 h-1 in March and April)
Fallow system after abandonment
Vísmia sp
CAPOEIRA (CAP) = natural second
growth
Low biomass; low plant diversity; exposed soil surface;
very low soil nutrient availability; poor soil structure and
biological activity
Fastening second growth after abandonment
Improved second growth
 Planting fast-growing
native trees
Fire suppression or decrease for new cropping
Land preparation without fire
 slash-and-choping
Use of abandoned or degraded land & second growth
enrichment as alternative for small farms in the tropics
9 year old AFS
Columbrina
Pupunha
Açaí
Agrossilvicultural System AS1
ASP1 – timber trees + pasture
Macrofauna in 5-year old Agroforestry Systems in Manaus, Brazil
Dry season
No . de an im ais (in d./m 2 )
Wet season
100
100
80
80
60
60
40
40
20
20
0
0
C UP
P AL
AR V
DES M
B R AC
Est ação ch uv o sa
E -L
C AP
C UP
P AL
AR V
DES M
B R AC
E -L
C AP
Est ação seca
Macrofauna density (ind/m2) in litter layer in wet and dry season, under
dominant tree species:
Cupuaçu (CUP), Palms (PAL), Planted timber trees (ARV), Desmodium
(DESM), Brachiaria (BRAC), Inter-rows (E-L) and Second growth (CAP).
Tapia-Coral et al., 1999
13 year old A
Aerial biomass and stocks of carbon and nutrients in 9 year old
Agroforestry Systems and Second Growth
Biomass and carbon
Nutrients
Biomass
Carbon
1400
120
1200
80
Nutrient kg ha-1
Dry W eight Mg ha-1
100
60
40
1000
Mg
800
Ca
K
600
P
400
20
N
200
0
0
Fruit
Palm
TP
SF
Fruit
Palm
TP
SF
McCaffery, Fernandes, Wandelli, Rondon, 2002

Climatic Change and/or Long
Distance Impacts in Amazonia
Fine litterfall production in primary forest in central
Amazon during El Niño year and under high atmospheric
CO2
Fabiana Rocha
2002-present
Production 1979-82 x 2002-present Plateau & Valley
Production 2002 (moderate El Niño)  higher
Average 2002-  ? higher than in 1979-82 ?
CWD : increase post El Niño events  decomposing
dead trees
Moisture controls fine litter layer respiration
dry litter)
3.5
3.0
-1
2.5
2
m oisture (g H O g
2.0
1.5
1.0
0.5
r
dry litter)
0
-1
2
adj
=0.36
p < 0.0001
0.0
respiration (ug CO g
2
50
100
150
200
250
300
350
sum of last 20 days rainfall (m m )
3.5
3.0
2.5
2.0
1.5
1.0
0.5
r
0.0
2
adj
=0.72
p < 0.0001
0
0.5
1
1.5
-1
m oisture (g H O g
2
2
2.5
Respiration fluxes from the litter
layer is sensitive to hydric stress
dry litter)
Chambers, 2003
Litter respiration fluxes
(susceptible to hydric stress)
controlled by moisture
-1
day )
1997 El Niño 2200 mm
-1
8.0
7.0
respiratory flux (kg C ha
respiratory flux (kg C ha
-1
-1
day )
Litter layer
6.0
5.0
4.0
3.0
2.0
total = 2.21 M g ha
-1
yr
-1
1.0
0
60
120
180
240
day of year
300
360
1999 La Niña 3200 mm
8.0
7.0
6.0
5.0
4.0
3.0
2.0
total = 2.61 M g ha
-1
yr
-1
1.0
0
60
120
180
240
300
day of year
Difference between rainy and dry years = ~0.4 Mg C ha-1 yr-1
Chambers, 2003
360
Litter fungi – very
susceptible to moisture
...like the lumniscent ones (night fungi)
Efects of the 2005 drought
0.2
Aragao (2007)
Changes
in basal
area of the
trees
m2 ha-1
per year
0.1
0
-0.1
-0.2
Before drought
Drought
2001-2003
2002-2004
SECA FLORESTA Experiment (LBA)
Simulating a drier climate in Amazonia
35–41% reduction in effective rainfall during 4.5 years in a
1 ha plot
Plant available water X Leaf Area Index
- Wood production was the most sensitive component of aboveground net primary productivity (ANPP) to drought, declining by
13 % the first year and up to 62 % thereafter.
- Litterfall declined only in the third year of drought (maximum
difference of 23 % below the control plot).
- Soil CO2 efflux and its 14C signature: no significant response
- ANPP: similar between plots in 1st year and declined by 41 %
during the subsequent treatment years, rebounding to only a 10
% difference during the first post-treatment year.
- Live aboveground carbon declined by 32.5 Mg ha through the
effects of drought on ANPP and tree mortality.
Thus: multi-year severe drought can substantially reduce
Amazon forest carbon stocks.
Beyond the internal recycling 

External contributions for nutrient cycling in
the Amazonian forest:

Rain water
Aerosols

Annual input of mineral nutrients (kg/ha)
in tropical forests: main sources:
Rains
Throughfall
151
15
33
P
3
11
3
K
15
12
114
Ca
37
14
26
Mg
14
4
21
Element
Litter
C
3.880
N
Luizão, 1989
Moist Deposition (rain water) in the
Amazonia: little or no phosphates
Volume Weighted
Mean (μM/l)
pH
H+
Cl-
NO3-
SO42-
Ca2+
Mg2+
Na+
K+
4.7
17.0
4.6
4.2
4.0
4.8
1.8
2.4
0.8
Balbina
(this work)
5.1
7.80
4.64
4.27
3.17
1.70
1.80
4.44
1.56
Rondonia
(this work)
5.1
7.91
1.69
9.50
0.19
0.42
0.04
0.61
0.26
Total deposition
(kg ha-1.yr-1)
H+
Cl-
NO3-
SO42-
Ca2+
Mg2+
Na+
K+
0.47
8.93
7.13
10.4
5.29
1.22
2.53
0.9
Balbina
(this work)
0.18
3.72
5.95
6.84
1.53
0.98
2.28
1.37
Rondonia
(this work)
0.05
0.39
3.70
0.20
0.12
0.01
0.09
0.08
Williams
(Central Amazonia)
Williams
(Central Amazonia)
From Pauliquevis et al., 2002
Tropical rain forests biomass today:
Africa: growing 0.63 (0.22-0.94) MgC/ha/yr
(79 plots, 163 ha – Lewis et al. 2009 Nature)
Combined tropical Africa, America and Asia:
Increment of 0.49 (0.29-0.66) MgC/ha/yr
(n=156; 562 ha; mean interval 1987-97
C sink = 1.3 PgC/yr (CI, 0.8-1.6) during last
years  ? Increase of atmospheric CO2?

Aerosol fertilization?
Sahara dust
deposition in
Amazonia
20 – 50 kg dust/ha/ano
Atmospheric input of N
and P from Sahara is
likely important only on
timescales of a few
millennia as opposed to
the hundreds of years
proposed by Swap et al.
From: Oliver Chadwick, 2002
Figure 1. Total deposition, total N, and total P deposition to northern South
America calculated from model outputs.
Aerosols and ecosystem Phosphorus fertilization
Okin et al. 2004 GBC: Semi-arid steppes Africa & Eurasia  significant
aerolian P inputs
In America: significant only on very old landscapes such as SE of USA
and Amazon Basin  highly dependant on aeolian depositions to
maintain long-term productivity
 Primary controller of soil P concentrations
Okin & Reheis 2002: Dramatic impact of dust emission on smaller scales
Amazon and Congo basins: larger additions of P from Sahara  shorter
turnover times
Modern-day P depositions in central Amazon = 35 kg/ha/yr
Artaxo et al. 2002: P-rich material derived from fires
Mahowald et al. 2008 GBC: on global scale, mineral aerosols are the
dominant source (82 %) of total-P
Distribution of experiments near the K34 main tower, Manaus
Medidas de fluxo de calor
sensível por infra-vermelho
Fluxo de CO2 e medidas
micrometeorológicas
Cintilômetro
Baixio
Medidas de transporte
horizontal de CO2, utilizando
anemômetros sônicos e
analisadores de CO2
Medidas de Fluxo de CO2 e
variáveis micrometeorológicas
Draino
K34
INSTRUMENTATION of the catchment
Hoping for a greener and better world
(www.lba/inpa.gov.br/lba)