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Field Study With Full Size Combine Harvesters Following the differences seen between the treatments, the question arose whether these were individually influenced by the soil type, too. From Table 19 it was obvious that all measured parameters were significantly influenced by the soil type. Table 19: General statistical analysis of rut parameters in relation to soil type (statistically different treatments are followed by the same letter) Soil Type Aver. Max. Depth (mm) Aver. Aver. Depth (mm) Average Rut Width (mm) Subsoiled 121a 86a 920a Shallow Tilled 59b 37b 800b Clay 83c 55c 840c LSD 9 8 36 Significant differences between the plot which received a subsoil treatment and the shallow plots were expected as initial soil density and therefore soil strength for the subsoiled plot was much lower. The significant differences between the shallowly tilled clay and sandy loam confirmed the theoretically expected difference due to soil strength. Comparing the results of the high inflated tyre vs. the tracked machine on the left hand side of Figure 61 showed the significant differences seen in rut depth visually in a the sandy loam subsoiled plot. On the right hand side the ruts caused by the normal inflated tyre can be seen, too, followed by the tracked machine on the left and in the far left the pronounced ruts are caused by the high inflation pressure tyres. Consequently in first instance an analysis of soil compaction caused by drive systems can be performed visually. However, as Ansorge and Godwin (2007a) showed on a stratified soil condition in the lab, the rut depths might be identical but the soil displacement might not. Therefore if differences are obvious, then these are there. However, if no differences are seen there can still be differences in the underlying soil. 4.1.4 Gravimetrical Dry Bulk Density In each treatment DBD was determined gravimetrically at two depths (150 and 300 mm) with three replications. Three control measurements were randomly taken on each field site before the experiment was conducted. Ph.D. Thesis Dirk Ansorge (2007) 76
Field Study With Full Size Combine Harvesters An analysis of variance was carried out for all the DBD data and showed that there were significant fixed effects from the treatment itself, the soil type, the depth at which the probe was taken and a significant interaction between the treatment and the soil type. Analyzing the data with respect to the overall effect of the treatment across all soil types showed that all treatments were significantly different from the control, yet there are no significant differences between the treatments. The estimated densities for the treatments were in corresponding order as the soil bin results and the results previously discussed. Table 20 shows the summary of this data. Table 20: DBD for field treatments, statistically identical DBD followed by the same letter Treatment Estimated DBD (g/cc) SE DF Control 1.352 a 0.0198 29 High Inflation Pressure 1.518 b 0.0214 29 Normal Inflation Pressure 1.517 b 0.0171 29 Tracked Machine 1.499 b 0.0171 29 The fixed effect of the soil type over all treatments showed a significant difference for both sandy loam soils from the clay treatment. The results from subsoiled and shallow tilled sandy loam were statistically identical which lead to the conclusion that the sandy loam soil had been compacted to a similar final state, indifferent from their initial density (data shown in Table 21). This was confirmed when looking at the penetrometer resistance in Figure 59 whereby the final penetrometer resistance was identical for the wheeled machine on both the shallow tilled and the subsoiled part of the sandy loam, but the track could maintain the subsoiled sandy loam at a lower final penetrometer resistance. Table 21: DBD for soil types and, statistically identical DBD followed by the same letter Soil Type Estimated DBD SE DF Clay Shallow Tilled 1.318 a 0.017 29 Sandy Loam Subsoiled 1.551 b 0.016 29 Sandy Loam Shallow Tilled 1.546 b 0.016 29 Ph.D. Thesis Dirk Ansorge (2007) 77
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Cranfield University School of Appl
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Abstract Ancillary experiments show
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Table of Contents TABLE OF CONTENTS
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Table of Contents 4.1.3 Analysis of
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Table of Contents 11.1.1.1 Comparis
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List of Figures and Tables Figure 3
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List of Figures and Tables Figure 1
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Nomenclature NOMENCLATURE Abbreviat
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Introduction 1 INTRODUCTION 1.1 Bac
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Introduction � Ansorge, D. and Go
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Introduction 1.2 Aim To elucidate t
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Introduction a) the soil compaction
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Experimental Methods 2.1.1.1 Test F
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Experimental Methods had been mount
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Experimental Methods track; the loa
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Experimental Methods 800/10.5/2.5 t
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Experimental Methods term. In the m
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Experimental Methods Soil Surface F
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Experimental Methods Depth (cm) 0 1
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Experimental Methods ence surface c
Page 41 and 42: Experimental Methods chine derives
Page 43 and 44: Experimental Methods depth. The dat
Page 45 and 46: Experimental Methods with water and
Page 47 and 48: Experimental Methods 2.4 Statistica
Page 49 and 50: Laboratory Studies Into Undercarria
Page 77 and 78: Field Study With Full Size Combine
Page 91: Field Study With Full Size Combine
Page 99 and 100: Alleviation of Soil Compaction Howe
Page 101 and 102: Alleviation of Soil Compaction not
Page 103 and 104: Alleviation of Soil Compaction in a
Page 105 and 106: Alleviation of Soil Compaction diff
Page 107 and 108: Soil Compaction Models sibilities t
Page 109 and 110: Soil Compaction Models depends on t
Page 111 and 112: Soil Compaction Models Wroth (1968)
Page 113 and 114: Soil Compaction Models however, the
Page 115 and 116: Soil Compaction Models level. Criti
Page 117 and 118: Soil Compaction Models Utilizing Ke
Page 119 and 120: Soil Compaction Models average of m
Page 121 and 122: Soil Compaction Models Depth (mm) -
Page 123 and 124: Soil Compaction Models ture content
Page 125 and 126: Soil Compaction Models with four ot
Page 127 and 128: Soil Compaction Models Predicted In
Page 129 and 130: Soil Compaction Models Depth (mm) -
Page 131 and 132: Soil Compaction Models and 13.7 % b
Page 133 and 134: Soil Compaction Models Rel. Density
Page 135 and 136: Soil Compaction Models VCL paramete
Page 137 and 138: Soil Compaction Models The approach
Page 139 and 140: Soil Compaction Models surface stay
Page 141 and 142: Soil Compaction Models This result
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Soil Compaction Models 6.6.1.3 Wate
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Soil Compaction Models σσ 1 (kPA)
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Soil Compaction Models pressure to
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Soil Compaction Models The response
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Soil Compaction Models On medium so
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Soil Compaction Models SOILFLEX tak
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Ancillary Experiments 7 ANCILLARY E
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Ancillary Experiments Average conta
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Ancillary Experiments In order to c
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Ancillary Experiments contrary, the
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Ancillary Experiments Figure 102: S
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Ancillary Experiments track and the
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Ancillary Experiments even when hav
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Ancillary Experiments 7.3.2 Influen
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Ancillary Experiments The results f
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Ancillary Experiments Figure 117: S
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Ancillary Experiments Contact Press
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Ancillary Experiments Figure 123: F
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Ancillary Experiments Sinkage (mm)
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Ancillary Experiments model which o
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Ancillary Experiments 7.3.5 The Inf
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Ancillary Experiments 7.3.7 Discuss
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Ancillary Experiments Terzaghi (194
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Ancillary Experiments contact area.
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Ancillary Experiments soil forward
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Conclusions � The longitudinal so
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Bibliography 10 BIBLIOGRAPHY Aboaba
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Bibliography Defossez, P., Richard,
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Bibliography Gregory, A.S.; Whalley
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Bibliography Lamande, M., Schjonnin
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Bibliography Seig, D., 1985. Soil C
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Appendix 11 APPENDIX Ph.D. Thesis D
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Appendix Figure 32: VCL sample at t
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Appendix comparison at the deepest
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Appendix Estimated Pressure (kPa) 2
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Appendix 11.1.1.2.1 SOCOMO One of t
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Appendix by Seig (1985) who showed
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Appendix Soil water content 15 % an
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Appendix Adapting critical state so
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Appendix density is obtained by add
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Appendix Table 5: Values of constan
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Appendix choice of a concentration
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Appendix 11.1.3.1 Dense/Hard and Lo
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Appendix 11.1.3.2 Stratified Soil C
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Appendix To summarize the ability t
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Appendix In the following the predi
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Appendix concentration factor of 4,
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Appendix 11.1.5.1 Confining Pressur
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Appendix Figure 24. The VCL created
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Appendix Rel. Density 2 1,9 1,8 1,7
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Appendix relation of � 1 to � 2
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Appendix Rel. Density 2 1,9 1,8 1,7
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Appendix Rel. Density 1,7 1,68 1,66
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Appendix Depth (mm) 0,0 100,0 200,0
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Appendix Figure 42: Plate in cookin
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Appendix � z � � �� k c p
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Appendix Table 8: n and k depending
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Appendix to the plate sinkage equat
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Appendix with a slight deviation fr
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Appendix Table 12: DBD values for a
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