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Presentation at WCCA5 2011 by Mariela Fuentes, Luc Dendooven, Fernando De León, Jorge Etchevers, Claudia Hidalgo, Bram Govaerts
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Mariela Fuentes, Luc Dendooven, Fernando De León,
Jorge Etchevers, Claudia Hidalgo, Bram Govaerts
CONSERVATION AGRICULTURE,
AGGREGATE STABILITY AND THE
ORGANIC CARBON DISTRIBUTION IN
SOIL AGGREGATES
Carbon dynamics
*Soil quality
*Mitigation of climate change
Conservation agriculture vs conventional
Aggregates
Evaluated aggregate size distribution, and carbon
distribution in three aggregate fractions during a cropping
cycle of a soil cropped with maize and wheat in Central
Mexico.
Conventional tillage Zero tillage
with without with without
residues residues residues residues
rotation maize-wheat,wheat-maize
monoculture (maize and wheat)
EXPERIMENTAL STATION OF “EL BATÁN”
CIMMYTZTM+r / -r
ZTR+r / -r
CTM+r / -r
CTR+r /-r
*The experiment was set up in 1991
*Subtropical highlands of central Mexico
*Haplic Phaeozem
25% sand 37% silt and 38% clay
Samples undisturbed
0-5 and 5-10 cm soil layers
C autoanalyzer (TOC-5050A
Total Organic Carbon, Shimadzu©)
micro-aggregates (< 0.25 mm)
small macro-aggregates (0.25 to 1 mm)
large macro-aggregates (1 to 8 mm)
0
10
20
30
40
50
60
70
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
Ag
gre
gate
s d
istr
ibu
tio
n (
%)
Aggregates 1-8mm (LSD 0.23) Aggregates 0.25-1mm (LSD 0.08)
Aggregates <0.25 mm (LSD 0.14)
0
0.4
0.8
1.2
1.6
2
Mean
Weig
ht
Dia
mete
r (m
m)
0
10
20
30
40
50
60
70
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
Ag
gre
gat
es d
istr
ibuti
on
(%
)
Aggregates 1-8mm (LSD 0.11) Aggregates 0.25-1mm (LSD 0.24)Aggregates <0.25 mm (LSD .03) MWD (LSD .39)
0
0.4
0.8
1.2
1.6
2
Mea
n W
eig
ht
Dia
met
er (
mm
)
0 to 5 cm
0
10
20
30
40
50
60
70
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
Ag
gre
gate
s d
istr
ibu
tio
n (
%)
Aggregates 1-8mm (LSD 0.18) Aggregates 0.25-1mm (LSD 0.14)Aggregates <0.25 mm (LSD 0.18)
0
0.4
0.8
1.2
1.6
2
Mean
Weig
ht
Dia
mete
r (m
m)
0
10
20
30
40
50
60
70
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
Ag
gre
gat
es d
istr
ibu
tio
n (
%)
Aggregates 1-8mm (LSD 0.22) Aggregates 0.25-1mm (LSD 0.16)
Aggregates <0.25 mm (LSD 0.17)
0
0.2
0.4
0.6
0.8
1
1.2
Mean
Weig
ht
dia
mete
r (m
m)
MWD 0.57
MWD 0.29
MWD 0.7
5 to 10 cmMAIZE
WHEAT
0
5
10
15
20
25
30
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
Org
an
ic C
arb
on
(g k
g-1)
Aggregates 1-8mm (LSD 12.4)
Aggregates 0.25-1mm (LSD 4.98)
Aggregates <0.25 mm (LSD 8.13)
0
5
10
15
20
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
Org
an
ic C
arb
on
(g k
g-1)
Aggregates 1-8mm (LSD 3.9)
Aggregates 0.25-1mm (LSD 2.18)
Aggregates <0.25 mm (LSD 4.43)
0
5
10
15
20
25
30
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
Org
an
ic C
arb
on
(g
kg-1
)
Aggregates 1-8mm (LSD 6.83)
Aggregates 0.25-1mm (LSD 4.11)
Aggregates <0.25 mm (LSD 5.88)
0
5
10
15
20
25
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
Org
an
ic C
arb
on
(g k
g-1)
Aggregates 1-8mm (LSD 4.99)
Aggregates 0.25-1mm (LSD 2.09)
Aggregates <0.25 mm (LSD 5.66)
MAIZE WHEAT0 to 5 cm
5 to 10 cm
0
10
20
30
40
50
60
70
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
SO
C c
on
trib
uti
on
(%
)
Aggregates 1-8mm (LSD 12.12)
Aggregates 0.25-1mm (LSD 9.22)
Aggregates <0.25 mm (LSD 11.27)
0
10
20
30
40
50
60
70
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
SO
C c
on
trib
uti
on
(%
)
Aggregates 1-8mm (LSD 10.14)Aggregates 0.25-1mm (LSD 14.5)Aggregates <0.25 mm (LSD 19.48)
MAIZE
0
10
20
30
40
50
60
70
80
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
SO
C c
on
trib
uti
on
(%
)
Aggregates 1-8mm (LSD 27.87)
Aggregates 0.25-1mm (LSD 25.78)
Aggregates <0.25 mm (LSD 15.21)
0
10
20
30
40
50
60
70
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
SO
C c
on
trib
uti
on
(%
)
Aggregates 1-8mm (LSD 15.21)
Aggregates 0.25-1mm (LSD 16.22)
Aggregates <0.25 mm (LSD 10.64)
WHEAT0 to 5 cm layer
5 to 10 cm layer
40.7%18
%
41.2 %
SOC
38%
SOC
43.2%
SOC
18.9%
50 %
25 %25 %
SOC
28.6%
SOC
17.4 %
SOC
54%
8 %
56 %
36 %
55.2%
SOC
SOC
37.4% SOC
7.2%
27.5% 11 %
61.5%
SOC
26.4% SOC
9.37%
62.7%
SOC
CONSERVATION AGRICULTURE CONVENTIONAL AGRICULTURE
0 to 5 cm layer
Total SOC= 22 g kg-1
Aggregates size distribution and their SOC contribution
Large macro-aggregates small macro-aggregates microaggregates
5 to 10 cm layer
Total SOC= 15 g kg-1
0 to 5 cm layer
Total SOC= 13 g kg-1
0 to 5 cm layer
Total SOC= 13 g kg-1
*The most attractive system to maximize C retention was
zero tillage with residue (rotation or monoculture)
*The retention of C depends mainly the small and
large macro-aggregates
CONCLUSION
Thank you very much
We know more about the
movement of the celestial
bodies than about the soil
underfoot
Da vinci
