Effects of afforestation on soil physical...
Transcript of Effects of afforestation on soil physical...
Effects of afforestation on soil physical properties
Mario Pérez Bidegain
Department of Soils and Water
Facultad de Agronomía-Udelar
September 12, 2018
Background
• Change from agriculture, or native pasture to afforestation
• Change on root system
• Change on Soil Organic Matter (SOM) supply/distribution
Results
Pérez Bidegain et al, 2001
Volumetric soil water content, soil erodibility, and runoff on different soil under Eucalyptus (8-10 yr old) and Pasture
**
**
NS
Results
• Water Drop Penetration Time (WDPT) for three vegetations:
native pasture, Pinus taeda and Eucalyptus grandis in a Ultisol
Acrisol Álbico
0,0
2,0
4,0
6,0
8,0
10,0
12,0
manejo
tiem
po
(seg
un
do
s)
campo
pino
eucalyptus
Rodriguez, J (2007)
• Water repellency increases after changing native pastures to Eucalyptus sp. and Pinus taeda.
• Water repellency is a consequence of microbiological and/or biochemical reactions.
• Organic hydrophobic compounds are present in the three soil uses, but their quantities were higher in afforested soils.
• An increase in hydrophobicity was associated to less Water Holding Capacity, principally in soils below eucalyptus vegetation.
Results
Results
0
100
200
300
400
500
600
700
800
0 20 40 60 80 100 120
Tin
e (
seco
nd
s)
Soil matric potential(-KPa)
Pasture
Row
Between rows
Slightly
Moderately
Strong
Field Book for describing and sampling Soils V.3 NSSC-NRCS-USDA
Bentancor y Pérez Bidegain (2017, unplublished)
Results
• Norh region
• Hapludalfs y Hapludults
• Sand stones derived soils (Triassic)
• Slopes (8-15%)
• A horizon 50 to 100 cm deep (Sandy loam)
• Bt horizon (Sandy clay loam)
• Natural fertility: low
• Soil erosion risk: high
Results
99
A
C
A
Bt
80
D
F
A
E
Bt
C
38
104
72
Watersh.1
C
A1
A2
Bt
C
78
133 C
AB AB
48
60
114
Bt
Watersh.2
Results
Soil Horizon Depth Sand Silt Clay Organic
matter
pH
(H2O)
pH
(KCl)
cm % weight %
C (summit) A1 78 83.2 8.9 7.9 0.4 5.2 4.2
A2 21 80.1 9.5 10.4 0.3 5. 4.1
Bt 34 58.1 10.8 31.3 0.3 4.8 3.7
C 61.2 10.5 28.3 0.2 4.8 3.7
F
(footslope)
A 38 74.2 13.1 12.7 1.0 5.1 4.1
E 34 75.9 12.8 11.3 0.8 5.1 4.1
Bt 32 63.1 12.3 24.6 0.7 5.1 3.8
Results Soil bulk density (Mg.m-3), volumetric soil water content (-10kPa) and macroporosity in soil C (summit) in pasture and forest (10 yrs after the plantation)
Depth BD θ Mac
P Pine PIR P Pine PIR P Pine PIR
2.5-7.5 1.54 1.41 1.36 22.2 20.1 18.5 19.7 26.9 30.3
22.5-
27.5
1.53 1.51 1.49 15.8 19.5 17.7 26.5 23.6 26.1
78-99 1.54 1.46 1.48 20.5 18.1 17.8 21.6 26.8 26.5
99-133 1.44 1.38 1.55 33.5 34.1 16.6 12.2 13.6 4.8
Results
Depth BD θ Mac
P Pine PIR P Pine PIR P Pine PIR
2.5-7.5 1.47 1.29 1.34 24.2 25.2 22.4 20.1 26.4 27.1
22.5-
27.5
1.48 1.41 1.48 19.7 20.6 20.1 24.3 26.2 23.4
38-72 1.58 1.57 1.56 21.5 17.7 19.3 18.7 23.1 22.0
72-104 1.51 1.50 1.44 33.2 33.4 34.0 9.9 10.0 10.4
Soil bulk density (Mg.m-3), volumetric soil water content (-10kPa) and macroporosity in soil F (footslope) in pasture and forest (10 yrs after the plantation)
Results
• Constant head
• Surface: 5 cm depth
• Subsurface: 20 cm depth
• 12 yr old Pine
• Hapludalf
Results
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Row
Between row
Native pasture
cm.h-1
Lab saturated hydraulic conductivity
A a
a
B
Surface Sub surface
0.0 2.0 4.0 6.0 8.0 10.0 12.0
Row
Between row
Native pasture
cm.h-1
Lab saturated hydraulic conductivity
B
b
Aa
Results
0
100
200
300
400
500
600
01
/09
/20
02
14
/01
/20
04
28
/05
/20
05
10
/10
/20
06
22
/02
/20
08
06
/07
/20
09
18
/11
/20
10
01
/04
/20
12
14
/08
/20
13
27
/12
/20
14
10
/05
/20
16
Soil
wat
er
con
ten
t (m
m)
C Pasture
C Pine (row)
Summit
9/44 Pasture > Pine
4/44 Pine row > Pasture
Results
0
100
200
300
400
500
600
01
/09
/20
02
14
/01
/20
04
28
/05
/20
05
10
/10
/20
06
22
/02
/20
08
06
/07
/20
09
18
/11
/20
10
01
/04
/20
12
14
/08
/20
13
27
/12
/20
14
10
/05
/20
16
Soil
wat
er
con
ten
t (m
m)
F Pasture
F Pine (row)
Footslope
22/44 Pasture > Pine (row)
5/44 Pine (row) > Pasture
Conclusions
• Land use change (from pasture to afforestation) affected:
Soil physical propeties
Soil water dymamics (soil management, topographic position)
Soil water repellency ( Hidrological implications?)
Conclusions
• Link:
Soil physical and soil chemical properties
Soil management practices &
Hidrological implications
Thanks you [email protected]