Directory UMM :Data Elmu:jurnal:S:Soil & Tillage Research:Vol54.Issue3-4.Apr2000:
Soil & Tillage Research 54 (2000) 155±170
Changes in the properties of a Vertisol and responses
of wheat after compaction with harvester traf®c
B.J. Radforda, B.J. Bridgeb, R.J. Davisc, D. McGarryd,*,
U.P. Pillaie, J.F. Rickmanf, P.A. Walshg, D.F. Yuleh
a
Queensland Department of Natural Resources, LMB No. 1, Biloela, Qld 4715, Australia
Honorary Research Fellow, CSIRO Division of Land and Water, PO Box 2282, Toowoomba, Qld 4350, Australia
c
Bureau of Sugar Experiment Stations, PO Box 651, Bundaberg, Qld 4670, Australia
d
Queensland Department of Natural Resources, Meiers Road, Indooroopilly, Qld 4068, Australia
e
Agriculture Department, The University of Queensland, Brisbane, Qld 4072, Australia
f
Queensland Department of Primary Industries, PO Box 597, Dalby, Qld 4405, Australia
g
Kondinin Group, 26 The Esplanade, Wagga Wagga, NSW 2650, Australia
h
Queensland Department of Natural Resources, PO Box 736, Rockhampton, Qld 4702, Australia
b
Received 12 July 1999; received in revised form 18 November 1999; accepted 6 December 1999
Abstract
Soil compaction has been recognised as the greatest problem in terms of damage to Australia's soil resource. Compaction
by tractor and harvester tyres, related to traf®cking of wet soil, is one source of the problem. In this paper an array of soil
properties was measured before and immediately after the application of a known compaction force to a wet Vertisol. A local
grain harvester was used on soil that was just traf®cable; a common scenario at harvest. The primary aim was to determine the
changes in various soil properties in order to provide a ``benchmark'' against which the effectiveness of future remedial
treatments could be evaluated. A secondary aim was a comparison of the measurements' ef®ciency to assess a soil's structural
degradation status. Also assessed was the subsequent effect of the applied compaction on wheat growth and yield in the
following cropping season. Nine of the soil properties measured gave statistically signi®cant differences as a result of the soil
compaction. Differences were mostly restricted to the top 0.2 m of the soil. The greatest measured depth of effect was
decreased soil porosity to 0.4 m measured from intact soil clods. There was 72% emergence of the wheat crop planted into the
compact soil and 93% in the uncompact soil. Wheat yield, however, was not affected by the compaction. This may
demonstrate that wheat, growing on a full pro®le of stored soil water as did the current crop, may be little affected by
compaction. Also, wheat may have potential to facilitate rapid repair of the damage in a Vertisol such as the current soil by
drying the topsoil between rainfall events so increasing shrinking and swelling cycles. If this is true, then sowing a suitable
crop species in a Vertisol may be a better option than tillage for repairing compaction damage by agricultural traf®c. # 2000
Elsevier Science B.V. All rights reserved.
Keywords: Compaction; Bulk density; Hydraulic conductivity; Penetration resistance; Soil shear strength; Soil deformation
*
Corresponding author. Tel.: 61-7-38969566; fax: 61-7-38969591.
E-mail address: [email protected] (D. McGarry)
0167-1987/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved.
PII: S 0 1 6 7 - 1 9 8 7 ( 0 0 ) 0 0 0 9 1 - X
156
B.J. Radford et al. / Soil & Tillage Research 54 (2000) 155±170
1. Introduction
Worldwide, soil compaction is said to affect 68
million hectares of land principally from vehicular
traf®c (Flowers and Lal, 1998). In the Australian
context, soil compaction has been ranked as the greatest problem in terms of damage to Australia's soil
resource (Williams, 1998) and is ubiquitous to all soils
and farming systems across several regions of at least
one State (McGarry, 1993). Alakukku (1996a,b) and
Wu et al. (1997) link the increase in the weight of farm
machinery in recent decades with progressive subsoil
damage and review work on persistent subsoil physical degradation. Tullberg (1990) estimated that over
30% of ground area is traf®cked by the tyres of heavy
machinery even in genuine zero tillage systems (one
pass at sowing). Under the more realistic circumstances of minimum tillage the ®gure is likely to
exceed 60% and in conventional tillage practice it
almost certainly exceeds 100% during one cropping
cycle (Soane et al., 1982; Erbach, 1986). The ®rst pass
of a wheel is known to cause a major portion of the
total soil compaction (Burger et al., 1983; Koger et al.,
1983; Pollock et al., 1984). The depth of the effect of
compaction varies widely. Flowers and Lal (1998)
review works where increased bulk density has been
measured in the 0.1±0.35, 0.05±0.1, to 0.5 and to 0.6 m
layers.
There is often a tenuous link between measuring
and/or observing soil compaction and measuring associated reductions in crop yield due to complex interactions between crop growth, soil properties and
seasonal weather conditions (Earl, 1997; Connolly,
1998). Flowers and Lal (1998) give examples where
high axle loads have both in¯uenced and not in¯uenced yields of subsequent crops. In a review of crop
susceptibility to compaction in the tropics, Kayombo
and Lal (1994) do not present wheat (the crop grown in
the current experiment) as susceptible. Pillai and
McGarry (1999), assessing the relative ability of four
tropical crops to biologically alleviate soil compaction
of a Vertisol, found that wheat was relatively slow in
ameliorating a compacted upper subsoil.
Damage from high axle loads increases when the
soil is wet because wet soil has reduced strength
(Kirby and Kirchhoff, 1990). Wheel slip also increases
wheel damage (Soane et al., 1981) due to shear
processes in the soil, which occur particularly when
the soil is wet (Kirby and Kirchhoff, 1990). High tyre
in¯ation pressures also increase wheel damage (Soane
et al., 1981; Rickman and Chanasyk, 1988). In a study
that aimed to determine the soil moisture contents at
which a sandy loam and clay loam are most compactible, Mapfumo and Chanasyk (1998) concluded that
the ®ner textured clay loam was compactible over a
wide range of moisture contents Ð from ®eld capacity
to below the plastic limit.
In this paper several soil properties were measured
before and immediately after the application of a
known compaction force to a wet clay soil. The
primary aim was to determine the change in these
soil properties to relate changes with wheat yield
measured in the following cropping season. A secondary aim was a comparison of the measurements'
ef®ciency to assess a soil's structural degradation
status. Future work will measure the nature and rate
of repair of the structure degradation at the experimental site under various, practicable farm management strategies.
2. Methods and materials
2.1. The site, soil and cropping system
The site is located in a ®eld adjoining the Queensland Department of Primary Industries Research Station, Biloela, Qld, Australia (latitude 248220 S,
longitude 1508310 E, altitude 173 m). The site was
cleared in the 1930s to grow irrigated crops. The
ground surface is relatively level (a slope of 0.2%)
and irrigation has been from above-ground sprinklers.
The soil at the site is a black cracking clay developed on an alluvium, locally termed Tognolini series
(Shields, 1989) or Vertisol (Soil Survey Staff, 1975).
Four soil horizons (Ap, B21, B22 and D) were
described to 1.5 m in the soil pro®le, though there
are only small differences between them (Shields,
1989). The soil is brownish black with no mottles
and a medium to heavy clay, throughout. There are a
few medium calcareous nodules from 0.8 m. The soil
had minimal, visible structure degradation before the
experiment (P.G. Muller, pers. comm.). However, a
former owner reported a history of subsoil ``hardpan''
formation, because of which he deeply ripped the ®eld
in 1977 to a depth of 0.45 m. Selected soil physical
Table 1
Some physical and chemical properties of the soil pro®le (0±1.5 m)
Soil property
PSAa
0±0.05
0.05±0.1
0.1±0.2
0.2±0.3
0.3±0.4
0.4±0.5
0.5±0.6
0.6±0.9
0.9±1.2
1.2±1.5
a
CS (%)
FS (%)
S (%)
C (%)
3
3
2
2
2
1
3
3
3
7
19
19
19
18
17
21
22
25
30
37
31
28
27
27
22
24
24
26
21
20
45
48
53
51
55
53
51
47
43
35
R1b
pHc
ECd
(mS cmÿ1)
0.39
0.40
0.59
0.58
0.63
0.63
0.66
0.65
0.68
0.73
7.3
7.3
7.8
7.9
8.0
8.2
8.3
8.5
8.4
8.3
0.157
0.152
0.126
0.128
0.145
0.167
0.189
0.270
0.351
0.386
Cle
(mg kgÿ1)
7
6
18
33
50
65
85
146
269
373
Particle size analysis: CS, coarse sand (>200 mm); FS, ®ne sand (20±200 mm); S, silt (2±20 mm); C, clay (
Changes in the properties of a Vertisol and responses
of wheat after compaction with harvester traf®c
B.J. Radforda, B.J. Bridgeb, R.J. Davisc, D. McGarryd,*,
U.P. Pillaie, J.F. Rickmanf, P.A. Walshg, D.F. Yuleh
a
Queensland Department of Natural Resources, LMB No. 1, Biloela, Qld 4715, Australia
Honorary Research Fellow, CSIRO Division of Land and Water, PO Box 2282, Toowoomba, Qld 4350, Australia
c
Bureau of Sugar Experiment Stations, PO Box 651, Bundaberg, Qld 4670, Australia
d
Queensland Department of Natural Resources, Meiers Road, Indooroopilly, Qld 4068, Australia
e
Agriculture Department, The University of Queensland, Brisbane, Qld 4072, Australia
f
Queensland Department of Primary Industries, PO Box 597, Dalby, Qld 4405, Australia
g
Kondinin Group, 26 The Esplanade, Wagga Wagga, NSW 2650, Australia
h
Queensland Department of Natural Resources, PO Box 736, Rockhampton, Qld 4702, Australia
b
Received 12 July 1999; received in revised form 18 November 1999; accepted 6 December 1999
Abstract
Soil compaction has been recognised as the greatest problem in terms of damage to Australia's soil resource. Compaction
by tractor and harvester tyres, related to traf®cking of wet soil, is one source of the problem. In this paper an array of soil
properties was measured before and immediately after the application of a known compaction force to a wet Vertisol. A local
grain harvester was used on soil that was just traf®cable; a common scenario at harvest. The primary aim was to determine the
changes in various soil properties in order to provide a ``benchmark'' against which the effectiveness of future remedial
treatments could be evaluated. A secondary aim was a comparison of the measurements' ef®ciency to assess a soil's structural
degradation status. Also assessed was the subsequent effect of the applied compaction on wheat growth and yield in the
following cropping season. Nine of the soil properties measured gave statistically signi®cant differences as a result of the soil
compaction. Differences were mostly restricted to the top 0.2 m of the soil. The greatest measured depth of effect was
decreased soil porosity to 0.4 m measured from intact soil clods. There was 72% emergence of the wheat crop planted into the
compact soil and 93% in the uncompact soil. Wheat yield, however, was not affected by the compaction. This may
demonstrate that wheat, growing on a full pro®le of stored soil water as did the current crop, may be little affected by
compaction. Also, wheat may have potential to facilitate rapid repair of the damage in a Vertisol such as the current soil by
drying the topsoil between rainfall events so increasing shrinking and swelling cycles. If this is true, then sowing a suitable
crop species in a Vertisol may be a better option than tillage for repairing compaction damage by agricultural traf®c. # 2000
Elsevier Science B.V. All rights reserved.
Keywords: Compaction; Bulk density; Hydraulic conductivity; Penetration resistance; Soil shear strength; Soil deformation
*
Corresponding author. Tel.: 61-7-38969566; fax: 61-7-38969591.
E-mail address: [email protected] (D. McGarry)
0167-1987/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved.
PII: S 0 1 6 7 - 1 9 8 7 ( 0 0 ) 0 0 0 9 1 - X
156
B.J. Radford et al. / Soil & Tillage Research 54 (2000) 155±170
1. Introduction
Worldwide, soil compaction is said to affect 68
million hectares of land principally from vehicular
traf®c (Flowers and Lal, 1998). In the Australian
context, soil compaction has been ranked as the greatest problem in terms of damage to Australia's soil
resource (Williams, 1998) and is ubiquitous to all soils
and farming systems across several regions of at least
one State (McGarry, 1993). Alakukku (1996a,b) and
Wu et al. (1997) link the increase in the weight of farm
machinery in recent decades with progressive subsoil
damage and review work on persistent subsoil physical degradation. Tullberg (1990) estimated that over
30% of ground area is traf®cked by the tyres of heavy
machinery even in genuine zero tillage systems (one
pass at sowing). Under the more realistic circumstances of minimum tillage the ®gure is likely to
exceed 60% and in conventional tillage practice it
almost certainly exceeds 100% during one cropping
cycle (Soane et al., 1982; Erbach, 1986). The ®rst pass
of a wheel is known to cause a major portion of the
total soil compaction (Burger et al., 1983; Koger et al.,
1983; Pollock et al., 1984). The depth of the effect of
compaction varies widely. Flowers and Lal (1998)
review works where increased bulk density has been
measured in the 0.1±0.35, 0.05±0.1, to 0.5 and to 0.6 m
layers.
There is often a tenuous link between measuring
and/or observing soil compaction and measuring associated reductions in crop yield due to complex interactions between crop growth, soil properties and
seasonal weather conditions (Earl, 1997; Connolly,
1998). Flowers and Lal (1998) give examples where
high axle loads have both in¯uenced and not in¯uenced yields of subsequent crops. In a review of crop
susceptibility to compaction in the tropics, Kayombo
and Lal (1994) do not present wheat (the crop grown in
the current experiment) as susceptible. Pillai and
McGarry (1999), assessing the relative ability of four
tropical crops to biologically alleviate soil compaction
of a Vertisol, found that wheat was relatively slow in
ameliorating a compacted upper subsoil.
Damage from high axle loads increases when the
soil is wet because wet soil has reduced strength
(Kirby and Kirchhoff, 1990). Wheel slip also increases
wheel damage (Soane et al., 1981) due to shear
processes in the soil, which occur particularly when
the soil is wet (Kirby and Kirchhoff, 1990). High tyre
in¯ation pressures also increase wheel damage (Soane
et al., 1981; Rickman and Chanasyk, 1988). In a study
that aimed to determine the soil moisture contents at
which a sandy loam and clay loam are most compactible, Mapfumo and Chanasyk (1998) concluded that
the ®ner textured clay loam was compactible over a
wide range of moisture contents Ð from ®eld capacity
to below the plastic limit.
In this paper several soil properties were measured
before and immediately after the application of a
known compaction force to a wet clay soil. The
primary aim was to determine the change in these
soil properties to relate changes with wheat yield
measured in the following cropping season. A secondary aim was a comparison of the measurements'
ef®ciency to assess a soil's structural degradation
status. Future work will measure the nature and rate
of repair of the structure degradation at the experimental site under various, practicable farm management strategies.
2. Methods and materials
2.1. The site, soil and cropping system
The site is located in a ®eld adjoining the Queensland Department of Primary Industries Research Station, Biloela, Qld, Australia (latitude 248220 S,
longitude 1508310 E, altitude 173 m). The site was
cleared in the 1930s to grow irrigated crops. The
ground surface is relatively level (a slope of 0.2%)
and irrigation has been from above-ground sprinklers.
The soil at the site is a black cracking clay developed on an alluvium, locally termed Tognolini series
(Shields, 1989) or Vertisol (Soil Survey Staff, 1975).
Four soil horizons (Ap, B21, B22 and D) were
described to 1.5 m in the soil pro®le, though there
are only small differences between them (Shields,
1989). The soil is brownish black with no mottles
and a medium to heavy clay, throughout. There are a
few medium calcareous nodules from 0.8 m. The soil
had minimal, visible structure degradation before the
experiment (P.G. Muller, pers. comm.). However, a
former owner reported a history of subsoil ``hardpan''
formation, because of which he deeply ripped the ®eld
in 1977 to a depth of 0.45 m. Selected soil physical
Table 1
Some physical and chemical properties of the soil pro®le (0±1.5 m)
Soil property
PSAa
0±0.05
0.05±0.1
0.1±0.2
0.2±0.3
0.3±0.4
0.4±0.5
0.5±0.6
0.6±0.9
0.9±1.2
1.2±1.5
a
CS (%)
FS (%)
S (%)
C (%)
3
3
2
2
2
1
3
3
3
7
19
19
19
18
17
21
22
25
30
37
31
28
27
27
22
24
24
26
21
20
45
48
53
51
55
53
51
47
43
35
R1b
pHc
ECd
(mS cmÿ1)
0.39
0.40
0.59
0.58
0.63
0.63
0.66
0.65
0.68
0.73
7.3
7.3
7.8
7.9
8.0
8.2
8.3
8.5
8.4
8.3
0.157
0.152
0.126
0.128
0.145
0.167
0.189
0.270
0.351
0.386
Cle
(mg kgÿ1)
7
6
18
33
50
65
85
146
269
373
Particle size analysis: CS, coarse sand (>200 mm); FS, ®ne sand (20±200 mm); S, silt (2±20 mm); C, clay (