asabepaper-mbsk06-101

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The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect theofficial position of ASABE, and its printing and distribution does not constitute an endorsement of views which may be expressed.Technical presentations are not subject to the formal peer review process, therefore, they are not to be presented as refereed publications.Citation of this work should state that it is from an ASABE Section Meeting paper. EXAMPLE: Author's Last Name, Initials. 2006. Title ofPresentation. ASABE Section Meeting Paper No. xxxx. St. Joseph, Mich.: ASABE. For information about securing permission to reprint orreproduce a technical presentation, please contact ASABE at [email protected] or 269-429-0300

(2950 Niles Road, St. Joseph, MI 49085-9659 USA).

The Canadian Society for

BioengineeringThe Canadian society for engineering in agricultural,

food, environmental, and biological systems.

A CSBE/ASABE Inter Sect ional MeetingPresentation

Paper Number: MBSK 06-101

SOIL CONE INDEX ESTIMATION FOR DIFFERENT TILLAGE SYSTEMS

Arun KumarDepartment of Biosystems Engineering, University of Manitoba, Winnipeg, MB, Canada R3T 5V6

Ying ChenDepartment of Biosystems Engineering, University of Manitoba, Winnipeg, MB, Canada R3T 5V6

Shafiqur Rahman

Iowa state university,61C Schilletter Village Ames, Iowa, 50010 USA

Written for presentation at the(2006 CSBE/ASABE North Central Inter Sectional Meeting)

Sponsored by CSBE/ASABESaskatoon,Saskatchewan

October 5-7, 2006Abstract.Soil cone index (CI) is a mechanical property which affects soil compaction and plant root

development. In this study, data reported in the literature relating CI to tillage practices were

compiled. Two different tillage practices were included and they were no-tillage and conventional

tillage. Based on the literature data, linear regression equations were proposed to estimate CI for

each tillage system. Those equations incorporate basic soil variables such as texture and physical

properties. Values of CI decrease with the increase in clay content, and increase with the increase in

sand and silt contents. CI varies directly with bulk density and depth, and inversely with moisture

content.The regression equations will be validated with field data from Manitoba.

.

Keywords.Cone index, Tillage, Model, Soil texture


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The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect theofficial position of ASABE, and its printing and distribution does not constitute an endorsement of views which may be expressed. Technicalpresentations are not subject to the formal peer review process, therefore, they are not to be presented as refereed publications. Citation ofthis work should state that it is from an ASABE Section Meeting paper. EXAMPLE: Author's Last Name, Initials. 2006. Title of Presentation.

ASABE Section Meeting Paper No. xxxx. St. Joseph, Mich.: ASABE. For information about securing permission to reprint or reproduce atechnical presentation, please contact ASABE at [email protected] or 269-429-0300


INTRODUCTION

The most common parameters used to assess soil strength in tillage studies are resistance to penetration

and bulk density. Soil resistance as measured by cone index (CI) can be much easily and more rapidly

measured than soil bulk density and is widely used for assessment of compacting and loosening effectsof agricultural implements (Bedard et al. 1997; Tessier et al. 1997). Soil CI varies with soil properties

such as water content, bulk density, texture, and organic matter (Taylor and Gardner 1963; Camp and

Lund 1968; Pempural 1987).

Cone index is greatly influenced by tillage types. Tillage for seedbed preparation and weed

control modifies soil structure. For instance, conventional plowing generally results in loose soil

structure in the tilled layer while the no tillage leaves the soil relatively intact (Chen 1993). Soil

resistance as measured with a penetrometer has been observed to be more sensitive than bulk density to

different tillage management systems (Bauder et al. 1981; Pidgeon and Soane 1977). Pidgeon and

Soane 1977 reported that though an equilibrium density is achieved within the tillage zone under a

particular tillage system after initial changes in density, CI continuous to increase with time. Previous

research has shown that soil bulk density and /or CI are greater in no tillage than conventional tillage

systems (Elhers et al. 1983; Roth et al. 1988; Chen et al. 2004; Bueno, 2006). Frazen et al. (1994)

observed significantly smaller cone index values under no-tillage down to 0.10 m depth due to

mulching.

Along with tillage practices, soil physical properties (soil moisture content, organic matter and

density) also influence CI. Therefore, some researchers have tried to separate the direct effect of tillage

on CI from its indirect effect on water content and density in different ways to allow better comparison.

Busscher et al. (1997) adjusted different functions to correct cone index values from water content.

Others used analysis of covariance to reduce the effect of water content and density in the CI

comparisons (Yasin et al. 1993; Franzen et al. 1994). After correction, the dependence of CI on these

variables is reduced (Busscher et al 1997). Several researchers (Ayers and Perumpral 1982; Busscher et

al. 1997; Ohu et al. 1988) studied the relationship between CI and soil water content. Ayers and

Perumpral (1982) found a direct relationship between CI and bulk density. Busscher et al. (1997) found

an inverse relationship between CI and water content while, Ohu et al. (1988) found an exponential


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relationship between CI and water content for loams and clays. This conflicting result may be due to

soil physical properties as well as different tillage practices. Yasin et al. (1993) found cubic

relationship between cone index and depth. Therefore, better CI prediction model should incorporate

both tillage and soil physical properties. Various methods have been tried with limited success to

reduce the effects of soil water content and bulk density in the analysis of CI data.

Apart from the tillage and soil factors the CI is also affected by the penetometer device and the

operational procedures. Commonly used penetrometers include pocket, cone, and small diameter

friction sleeve cone types (Lowery and Morrison, 2002). Various types of cone penetrometer such as

static, quasi static, dynamic and their applications have been comprehensively reviewed by Pempural

(1987)

Few studies have been conducted to relate tillage with CI. The development of above

mentioned prediction models require large sets of data. In this study, CI data in terms of tillage

practices and soil physical properties were extracted under different tillage practices and soil conditions

around the world. The main objective of this study was to develop model which incorporate tillage

effects into CI estimation based on the published data from available literature, and to validate the

model based on field data.

MATERIALS and METHODS

A database was complied from previously published studies. There were a number of studies on soil

cone index or penetration resistance, however, only those related to tillage studies since 1980 were

used in the present study. The final database based on the previously published studies around the

world has been presented in Table 1. For the model validation, CI measurements will be undertaken for

different tillage systems from different fields in Manitoba, Canada.

Table1. Description of literature data sources from which the regression equations were developed.

Author Location Soil texture Tillage practices

Bauder et al., 1981 Minnesota, USA Nicollet Clay loam Plow, Chisel, NT

Brye et al., 2004 Arkansas, USA Stuttgart Silt loam Disk harrow, Chisel, Cultivator

Busscher et al., 1995 Florence, SC, USA Norfolk Loamy sand NT

Busscher et al., 1997 Florence, SC, USA Norfolk Loamy sand Disk harrow

Busscher et al., 2000 Florence, SC, USA Goldsboro Loamy sand Disk harrow

Busscher et al., 2002 Florence, SC, USA Norfolk Loamy sand Disc harrow, Shank Para till


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Carter, 1987 PEI, Canada Sandy loam Plow, NT

Chaplin et al., 1986 Minnesota, USA Hubbard Loamy sand Plow, Chisel, NT,

Chen et al., 2004 Manitoba, Canada Red river Clay NT, cultivator

Ehlers et al., 1983 Germany Grey brown podzolic (Silt) Plow

Grant and Lafond, 1993 Saskatchewan, Canada Clay Chisel, NT

Hammel, 1989 Moscow, ID, USA Silt loam plow, chisel, NTHill, 1990 Mariland, USA Bertie Silt loam low, Disk harrow, NT

Karayel and Ozmerzi, 2002 Turkey Silty loam Chisel, disk harrow

Larney and Kladivko, 1989 Purdue, IN, USA Chalmers Silty clay loam Plow, disk harrow, NT

Lopez et al., 1996 Aragon, Spain Silty Clay loam Plow, disk harrow, NT

Materechera and Mloza-Banda, 1997 Lilongwe, Malawi Sandy clay loam Disk harrow, NT

McFarland et al., 1990 Texas, USA Weswood silt loam Disk harrow, NT

Mielke et al., 1984 Nebraska, USA Alliance Silt loam, loam Plow

Moreno et al., 1997 Seville, Spain Sandy clay loam Plow, chisel

Osunbitan, et al.,2005 Ile-Ife, Nigeria Oxic Tropudalf NT, Disc Plow

Pierce et al., 1992 East Lansing, MI, USA Riddles Loam chisel , NT

Tessier et al., 1997, Quebec, Canada Orthic Gleysoil Plow, cultivator

Taboada et al., 1998 Rolling Pampa, Argentina Sandy loam Plow, Disk harrow, NT

Unger and Fulton, 1990 Texas, USA Pullman Clay loam NT, Sweep plow

Unger and Jones, 1998 Texas, USA Pullman Clay loam NT

Vetsch and Randall, 2002 Rochester, MN, USA Port Byron Silt loam soil NT, Chisel

Voorhees, 1983 Minnesota, USA Nicollet Silty clay loam Plow, chisel, disk harrow

Wilkins et al., 2002 Oregon, USA Walla Walla Silt loam NT, Plow

Plow=Mould board plow

NT= no-tillage

Compilation of the database

Constraints associated with data collection In most of the published studies two different cone

angles (i.e. 30 and 60) with different types of base diameter (ranged from 10.5 to 21.0 mm) were used.

In few cases, either the moisture content or the bulk density data were not available. To avoid any

biasness, only those data were included in the data base for which all information is available. Soil

textural variables (sand, silt, and clay content) were not always available in published studies. In that

case, textural variables were derived from the general soil textural class description (Shirazi and

Boersma 1984).


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Data classification category General classification of the data was made, as the data compiled

was from various studies which interpreted results from different aspects. The data was mainly divided

into two main categories which were tillage types and soil textural classes. The collected database was

categorized into no- tillage and conventional tillage for which further analysis was conducted.

Soil profile The depth of soil strata to be considered must be established. Depth varies substantially

according to different studies. In conventional tillage, depending on the tillage implements used, the

soil strata up to a depth of 200 mm is affected. Therefore, the soil profile within 0- 200 mm was

considered to characterize the CI for the tilled layer as defined by Chen et al. (1998) and Wilkins et al.

(2002). Similarly, in no tillage system though no seed bed preparation operations are performed, the

same soil strata of 0-200 was used to characterize CI for comparison purpose. The database

characterizes soils with clay, silt and sand contents.

Soil cone index and other soil parameters measurement Field measurement of soil cone

index was conducted in 2006 using Rimik cone penetrometer (Model CP 20, Agridy Rimik Pty. Ltd.,

Toowoomba, Australia) having cone base area of 129 mm2and an apex angle of 30. The penetrometer

had a load cell, a depth position sensor and a datalogger. Signals from the load cell and position

indicator were received by the data logger and program was used to convert signals to penetration

resistance force and position. The penetrometer was pushed into the soil manually at a speed of

approximately 0.30 mms-1

(ASAE 2000). At each location three measurements were taken at 25 mm

intervals upto a depth of 200 mm. CI readings were taken at 20 locations in both NT and CT fields.Also, soil samples for bulk density were taken up to a depth of 0-200 mm from 6 locations in each

field. Soil samples were collected from each site for determining texture. The sites selected were St

Agathe, Oakville, Point and Carman in Manitoba for field data collection.

Data analysis

Data obtained from the literature were regrouped into no tillage and conventional tillage system and

were further divided according to different soil strata and type of tillage system. Regression analysis

was used to determine the relationship between soil texture independent variables such as clay, silt, and

sand content, and dependent variable cone index (CI). Also, regression analysis was performed to


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establish relationship between independent variables namely density, depth and moisture content, and

dependent variable CI. Statistical evaluation procedure will be used to test the performance of model

with the field-measured data from this study. These methods include: coefficient of determination (R2)

which evaluates the degree of association between data points and predicted value.

MODEL DEVELOPMENT

Soil cone index for different tillage

Within conventional tillage, the type of implement and number of passes vary from one study to

another. It was assumed that for a conventional tillage system, the tillage implements have the same

effect on CI. This assumption was based on the fact that the purpose of conventional tillage is to

prepare a good seed bed by a combination of tillage implements to create favorable environment for

plant growth. In this process regardless of implements used the porosity of the soil changes by way of

breaking large aggregate clods and filling the large void spaces.

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 0.1 0.2 0.3

Depth (m)

CI(M

pa)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 0.1 0.2 0.3

Depth(m)

CI(M

pa)

(a) (b)

Figure 1 Relationship of CI vs depth under (a) no tillage and (c) conventional tillage


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CI values showed a general tendency to increase with depth under NT and CT (Fig 1). CI with depth

has a fairly well linear relationship (R2= 0.172) under CT and the increase is much steeper in CT than

in NT.

The relationships of independent variables with the dependent variable (CI) were mainly limited to the

influence soil strata as affected by the tillage type and can be expressed by the expression

CI = a + bX

Where, CI = Cone index

a = constant

b = slope

X = independent parameter

Regression results of CI with soil texture and physical properties are presented in Table 2.

Table 2. Regression results of CI and soil texture (sand, silt and clay content), bulk density, moisture

content, and depth under no tillage and conventional tillage.

Tillage

system

Independent

parameter

Slope Intercept R2 F P

NT Sand 0.023 0.046 0.224 14.69 0.000

Clay -0.021 2.223 0.19011.78 0.001

Silt 0.0194 1.100 0.179 18.34 0.000

Density 1.481 -0.305 0.062 4.27 0.042

Moisture content -0.064 3.337 0.231 15.35 0.000

Depth 2.125 1.313 0.012 0.60 0.439

CT Sand 0.006 0.982 0.023 1.60 0.191

Clay -0.014 1.590 0.105 7.95 0.004

Silt 0.009 0.775 0.0372 2.66 0.106

Density 4.970 -5.231 0.414 20.20 0.000

Moisture content -0.044 2.211 0.160 12.32 0.000


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Depth 6.904 0.366 0.172 18.72 0.000

Soil cone index for soil texture Sand, silt and clay content of the soil influences CI under NT and

CT systems. Analysis from the sub-dataset for no-tillage (NT) and conventional tillage (CT) indicate

that CI under both NT and CT increase with the increase in sand (Fig. 2) and silt fraction (Fig. 3) while

it decrease with the increase in clay content (Fig. 4). Regression results (Table 2) show fairly well

linear relationship between CI and sand content (R2 = 0.224), silt content (R

2 = 0.179) as well as

between clay content (R2= 0.190) under NT. The lines of slope for sand content and clay content are

steeper under NT as compared to CT. These results are consistent with those reported by Hummel et al.

(2004) who observed clay content as a significant variable in prediction of CI. Silt fraction was

recognized as a significant modifier for density and CI (Jones 1983).

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 20 40 60 80 100

Sand content ( %)

CI(MPa)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 20 40 60 80 100

Sand content ( %)

CI(Mpa)

(a) (b)

Figure 2 Relationship between CI and sand content for (a) no tillage (NT) and (b)

conventional tillage (CT) systems


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0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 20 40 60 80 100

Silt con tent (%)

CI(Mpa)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 20 40 60 80 100

Silt con tent (%)

CI(MPa)

(a) (b)

Figure 3 Relationship between CI and silt content under (a) no tillage (NT) and (b)

conventional tillage (CT) systems

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 20 40 60 80

Clay content, %

CI,MPa

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 20 40 60 80

Clay content, %

CI,MPa

(a) (b)

Figure 4 Relationship between CI and clay content of soil under no tillage (NT)

and (b) conventional tillage (CT) systems


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Soil cone index for different bulk density The graph in Figure 5 show relationship between CI and

bulk density. CI tends to increase with increase in bulk density (Fig. 5) under NT and CT conditions.

This is in agreement with previous investigators who reported that CI varies directly with bulk density

(Blanchar et al. 1978; Cruse et al. 1981; Stitt et al. 1982; Cassel 1983; Voorhees 1983). CI and bulk

density have a good linear relationship (R2= 0.414) under CT (Table 2). The slopes of lines are much

steeper in CT as compared to NT.

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0.7 1.2 1.7

Density, Mg/m3

CI(Mpa)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

1 1.2 1.4 1.6

Density( Mg/m3)

CI(MPa)

Figure 5 Relationship of CI vs density for (a) no tillage and (b) conventional tillage.

Soil cone index for different moisture content

The relationship in Figure 6 shows a decrease in CI values as the soil moisture content increases which

is in agreement with the results of several authors (Ayers and Perumpral 1982; Busscher et al. 1997;

Earl 1996; Mapfumo and Chanasyk 1998). The slope of lines for moisture content in NT is much

steeper compared to CT which suggests a greater variation of CI under NT, which agrees with the

results observed by Bueno et al. (2006).


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0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 20 40 60

Moisture con tent ( %)

CI(Mpa)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 10 20 30 40

Moisture con tent (%)

CI(M

Pa)

(a) (b)

Figure 6 Relationship of CI vs moisture content under (a) NT and (b) CT.

CONCLUSIONS

The data from the published studies conducted in different regions of the world were classified and

compiled into database. The database encompasses different soil classes and tillage systems. The

database was categorized into no tillage and conventional tillage systems. From testing various model

configurations, the best relationship between the CI values and soil texture and physical properties is

linear.

The analysis indicates decrease of CI with increasing clay fraction and decreasing sand and silt fraction

under NT and CT systems. CI increased with the increase in bulk density for both NT and CT.

In general low R2values in some equations indicate relatively high variability of the broad data set,

probably owing to different field conditions and tillage practices in different studies conducted in

different regions of the world.

REFERENCES

ASAE Standards, 2000. EP542 Feb99. Procedures for Using andReporting Data Obtained with the Soil

Cone Penetrometer.ASAE, St. Joseph, Mich.

Ayers,P. D., and J. V. Perumpral. 1982. Moisture and density effect on cone index. Transactions ASAE25(5): 1169-1172.


12/16




Bauder,J.W., G.W. Randall and J.B. swann. 1981. Effect of four continuous tillage systems on

mechanical impedence of a clay loam soil. Soil Science Society of America Journal 45: 802-806.

Bdard,Y., S. Tessier, C. Lagu, Y. Chen, and L. Chi. 1997. Soil compaction by manure spreaders

equipped with standard and oversized tires and multiple axles. Transactions ASAE 40(1): 37-43.

Blanchar, R.W., C.R. Edmonds, and J.M., Bradford, 1978. Root growth in cores formed from fragipan

and B2 horizons of hopson soil. Soil Science Society of America Journal 42: 437-440.

Brye, K.R., N.A. Slaton and R.J. Norman. 2005. Penetration resistance as affected by shallow cut land

leveling and cropping. Soil & Tillage Research 81: 1-13

Bueno, J. C., Amiama, J.L. Hernanz and J.M. Pereira. 2006. penetration resistance, soil water content,

and workability of grassland soils under two tillage systems. Transactions of the ASABE

49(4):875-882

Busscher, W.J., J.H. Edwards, M.J. Vepraskas and D.L. Karlen. 1995. residual effects of slit tillage and

subsoiling in a hardpan soil. Soil & Tillage Research 35: 115-123.

Busscher, W. J., P. J. Bauer, C. R. Camp, and R. E. Sojka. 1997. Correction of cone index for soil

water content differences in a coastal plain soil. Soil & Tillage Research 43(3-4): 205-217.

Busscher, W.J. and P.J. Bauer. 2002 Root growth and soil strength in conservation and conventional till

cotton. Prc. 25th

annual southern Conservation Tillage Conference for Sustainable agriculture.

Auburn,AL 24-26 June 2002.

Busscher, W.J., J.R. Frederick and P.J. Bauer. 2000. Timing effects of deep tillage on penetration

resistance and wheat and soybean yield. Soil Science Society of America Journal 64: 999-1003.

Camp, C.R. and Z.F. Lund.1968. Effect of mechanical impedance on cotton root growth.Transactions

ASAE 30(4): 188-190.

Carter,M. R. 1987. Physical properties of some Prince Edward Island soils in relation to their tillage

requirement and suitability for direct drilling. Canadian Journal of Soil Science 67(1): 473-487.

Cassel, D.K., 1983. Spatial and temporal variability of soil physical properties following tillage of a

norfolk loamy sand. Soil Science Society of America Journal 47: 196-201.

Chaplin, J., M. Lueders and D. Rugg. 1986. A study of compaction and crop yields in loamy sand soil

after seven years of reduced tillage. Transactions of the ASAE 29(2): 389-392.


13/16




Chen,Y. 1993. Soil thermal regime resulting from reduced tillage systems. Ph.D. thesis. Montreal,

Canada: Agricultural Engineering Dept., McGill Univ.

Chen, Y., S. Tessier, and J. Gallichand. 1998. Estimations of tillage effect on saturated hydraulic

conductivity. Canadian Agricultural Engineering 40(3):

Chen, Y., F.V. Monero, D.Lobb, S. Tessier and C. cavers. 2004. Effects of six tillage methods on

residue incorporation and crop performance in a heavy clay soil. Transactions of the ASAE 47(4):

1003-1010.

Cruse, R.M., D.K. Cassel, R.E. Stitt, and F.G., Averette.1981. Effect of particle surface roughness on

mechanical impedance of coarse textured soil materials. Soil Science Society of America Journal

45: 1210-1214.

Earl, R. 1996. Prediction of trafficability and workability using tensiometers.Journal of Agricultural

Engineering Research 63(1): 27-34.

Elhers,W., U. Kopke, F. Hesse and W. Bohm. 1983. Penetration resistance and root growth of oats in

tilled and untilled loess soil. Soil & Tillage Research.3:261-275.

Grant, C.A. and G.P. Lafond. 1993. The effect of tillage systems and crop sequences on bulk density

and penetration resistance on a clay soil in southern Saskatchewan, Canadian Journal of Soil

Science 73:223-232.

Gregorich,E.G., W.D. Reynolds, J.L.B. Culley, M.A. McGovern and W.E.Curnoe. 1993.Changes in

soil physical properties with depth in a conventionally tilled soil after no-tillage. Soil & Tillage

Research.26:289-299.

Hammel, J.E. 1989. Long term tillage and crop rotation effects on bulk density and soil impedence in

Northern Idaho. Soil Science Society of America Journal 53: 1515-1519.

Hill, R.L. 1990. Long term conventional and no-tillage effects on selected soil physical properties. Soil

Science Society of America Journal 54: 161-166

Hummel,J. W., I. S. Ahmad, S. C. Newman, K. A. Sudduth and S. T. Drummond.2004. Simultaneous soil

moisture and cone index measurement. Transactions of the ASAE 47(3): 607-618.

Jones, C.A. 1983. Effect of soil texture on critical bulk densities for root growth. Soil Science Society of

America Journal 47: 1208-1211


14/16




Larney,F.J. and E.J. Kladivko. 1989. Soil strength properties under four tillage systems at three long

term study sites in Indiana. Soil Science Society of America Journal 53: 1539-1545.

Lpez,M. V., J. L. Arre, and V. Snchez-Girn. 1996. A comparison between seasonal changes in

soil water storage and penetration resistance under conventional and conservation tillage systems

in Aragn. Soil & Tillage Research37(4): 251-271.

Lowery, B., and J. E. Morrison. 2002. Soil penetrometers and penetrability. InMethods of Soil

Analysis: Part 4. Physical Methods, 363388. 1st ed. J. H. Dane and C. G. Topp, eds. Madison,

Wisc.: ASACSSASSSA.

Mapfumo, E., and D. S. Chanasyk. 1998. Guidelines for safe trafficking and cultivation, and resistance-

density-moisture relations of three disturbed soils from Alberta. Soil & Tillage Research46(3-4):

193-202.Materechera, S.A. and H.R. Mloza-Banda. 1997. Soil penetration resistance, root growth and yield of

maize s influenced by tillage system on ridges in Malawi. Soil & Tillage Research41: 13-24.

McFarland, M.L., F.M. Hons and R.G. Lemon. 1990. Effects of tillage and cropping sequence on soil

physical properties. Soil & Tillage Research 17: 77-86.

Mielke, L.N., W.W. Wilhelm, K.A. Richards and C.R. Fenster. 1984. Soil physical characteristics of

reduced tillage in a wheat fallow system. Transactions of the ASAE 27(6): 1724-1728.

Moreno,F., F. Pelegrn, J. E. Fernndez, and J. M. Murillo. 1997. Soil physical properties, water

depletion, and crop development under traditional and conservation tillage in southern Spain. Soil

& Tillage Research41(1-2): 25-42.

Ohu, J.O. G.S.V. Raghvan and E. McKyes.1988. Cone index prediction of compacted soils.

Transactions of the ASAE 31(2): 306-310.

Osunbitan,J.A., D.J. Oyedele, K.O. Adekalu. 2005.Tillage effects on bulk density, hydraulic

conductivity and strength of a loamy sand soil in southwestern Nigeria. Soil & Tillage Research

82: 57-64.

Perumpral, J.V. 1987. Cone penetrometer applications- A review.Transactions of the ASAE 30(4):

939-944.


15/16




Pidgeon, J.D. and B.D. Soane.1977. Effects of tillage and direct drilling on soil properties during the

growing season in a long term barley mono-culture system. Journal of Agriculture Science

88:431-442.

Pierce, F.J., M.C. Fortin and M.J. Staton. 1992. Immediate and residual effects of zone tillage in

rotation with no tillage on soil physical properties and corn performance. Soil & Tillage Research

24: 149-165.

Roth, C.H., B. Meyer, H.G. Frede, and R. Derpsch.1988. Effect of mulch rates and tillage systems on

infiltrability and other soil physical properties of an Oxisol in Parana, Brazil.Soil & Tillage

Research 11: 81-89

Shirazi, M.A. and L. Boersma. 1984. A unifying quantitative analysis of soil texture. Soil Science

Society of America Journal 48: 1421-147.

Stitt, R.E., Cassel, D.K., Weed, S.B. and Welson, L.A., 1982. Mechanical impedance of tillage pans in

Atlantic Coastal Plains soil and relationships with soil physical, chemical and mineralogical

properties. Soil Science Society of America Journal 46: 100-106.

Taboada, M.A., F.G. Micucci, D.J. Cosentino and R.S. Lavado. 1998. Comparison of compaction

induced by conventional and zero tillage in two soils of the Rolling Pampa of Argentina. Soil &

Tillage Research 49: 57-63.

Taylor, H.M. and H.R. gardner. 1963. Penetration of cotton seedling tap roots as influenced by bulk

density, moisture content and strength of soil. Soil Science 96(3): 153-156.

Tessier,S., B. Lachance, C. Lagu, Y. Chen, L. Chi, and D. Bachand. 1997. Soil compaction reduction

with a modified one-way disker. Soil & Tillage Research42(1-2): 63-77.

Unger, P.W. and L.J. Fulton. 1990. Conventional and no-tillage effects on upper root zone soil

conditions.Soil & Tillage Research 16(4): 337-344.

Unger, P.W. and O.R. Jones. 1998. Long term tillage and cropping systems affect bulk density and

penetration resistance of soil cropped to dryland wheat and grain sorghum. Soil & Tillage

Research45: 39-57.

Vetsch, J. and G.W. Randall. 2002. Corn production as affected by tillage system and starter fertilizer.

Agronomy Journal 94: 532-540.


16/16




Voorhees, W.B. 1983. Relative effectiveness of tillage and natural forces in alleviating wheel induced

soil compaction. Soil Science Society of America Journal. 47: 129-133.

Wilkins, D.E., Changes in soil physical characteristics during transition from intensive tillage todirect

seeding.Transactions of the ASAE 45(4): 877-880.

Yasin, M., R.D.Grisso, L.L. Bashford, A.J. Jones and L.N. Mielke. 1993. Normalizing cone resistance

values by covariance analysis. Transactions of the ASAE 36(5): 1267-1270.

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