Download - Conservation agriculture, aggregate stability and the organic carbon distribution in soil aggregates
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