Crop roots and crop residues management: impacts on soil structure under zero tillage. Mariela...
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Transcript of Crop roots and crop residues management: impacts on soil structure under zero tillage. Mariela...
Mariela Fuentes, Paola Solís, Fernando De León, Carmen Gutiérrez, Bram Govaerts
CROP ROOTS AND CROP RESIDUES MANAGEMENT: IMPACTS ON SOIL STRUCTURE UNDER ZERO TILLAGE
*Soil physical quality
*Aggregation
*Pore systems
Conventional tillage Zero tillage
with without with withoutresidues residues residues residues
rotation maize-wheat,wheat-maize monoculture (maize and wheat)
EXPERIMENTAL STATION OF “EL BATÁN” CIMMYT
ZTM+r / -rZTR+r / -r
CTM+r / -rCTR+r /-r
*The experiment was set up in 1991
*Subtropical highlands of central Mexico
*Haplic Phaeozem
25% sand 37% silt and 38% clay
-2
-1
0
1
2ZTM+r
ZTM-r
ZTR+r
ZTR-r
CTM+r
CTM-r
CTR+r
CTR-r
YieldsPC1 (C,N,Ag,H)
PC2 (H,-RP,pH)
MAIZE
-2
-1
0
1
2ZTM+r
ZTM-r
ZTR+r
ZTR-r
CTM+r
CTM-r
CTR+r
CTR-r
YieldsPC1 (SOM, Moist., Ag.)
PC2 (pH, CE, Resist Penet, P)
WHEAT
0
10
20
30
40
50
60
70
ZTR+r ZTM+r CTR+r CTM+r ZTR-r ZTM-r CTR-r CTM-r
Agg
rega
tes
dist
ribu
tion
(%)
0
0.4
0.8
1.2
1.6
2
Mea
n W
eigh
t Dia
met
er (
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
Agg
rega
tes
dist
ribu
tion
(%)
0
0.4
0.8
1.2
1.6
2
Mea
n W
eigh
t Dia
met
er (m
m)
Ag
gre
gat
es
dis
trib
uti
on
(%
)
Mea
n w
eig
th d
iam
met
er (
mm
)
0 to 5 cm 5 to 10 cm
WHEAT
AGGREGATES
Aggregates 1-8mm
Aggregates 0.25-1mm
Aggregates <0.25 mm
Evaluated the influence of two root systems (maize andwheat) and crop residues management on the soil pore system in different agriculture management
ZTM-r ZTM+r ZTR+r
0–5, 5-10, 10-15 and 15-20 cm depth2 samples for plot
TOTAL POROSITY
COMPOUND PACKING VOIDS
BIOPORES
FISSURES
Thin sections were processed Image-Pro®statistical analysis: linear model and analysis of variance
0
10
20
30
40
50
60
70
ZTMm-r ZTMw-r ZTMm+r ZTMw+r ZTRm+r ZTRw+r
Tot
al s
oil p
oros
ity
(%)
0 to 5 cm LSD 7.65 to 10 cm LSD 6.210 to 15 cm LSD 5.4 15 to 20 cm LSD 5.7
ZTR+r ZTMw+r ZTMm+r ZTMm-r
0–5 cm
5-10cm
10-15 cm
15-20 cm
Thin sections
channels or bioporescompound packing voids, fissures
0 a 5cm
0
10
20
30
40
50
60
70
ZTMm-r ZTMw-r ZTMm+r ZTMw+r ZTRm+r ZTRw+r
cm 1
00 m
-2
5-10cm
0
10
20
30
40
ZTMm-r ZTMw-r ZTMm+r ZTMw+r ZTRm+r ZTRw+r
cm 1
00 c
m-2
10-15 cm
0
5
10
15
20
25
ZTMm-r ZTMw-r ZTMm+r ZTMw+r ZTRm+r ZTRw+r
cm 1
00 c
m-2
15-20 cm
0
5
10
15
20
25
ZTMm-r ZTMw-r ZTMm+r ZTMw+r ZTRm+r ZTRw+r
cm 1
00cm
-2
Monoculture vs rotation
The root wheat-soil relation favors the formation of pores
The roots per se do not generate a fully satisfactory soil structure; it is necessary to keep crop residues at the soil surface.
Conservation agriculture improves soil porosity (crop rotations)
CONCLUSION
Thank you very much
We know more about the movement of the celestial bodies than about the soil underfoot
Da vinci