Interpreting Soil Test Results

Contents......Page 8
Foreword......Page 6
About the authors......Page 13
Preface......Page 14
Acknowledgments......Page 15
Introduction......Page 16
1.1 Where, how and when to sample......Page 18
1.2 The number of samples required to produce a soil map......Page 19
2.1.1 The relationship between field texture and particle size......Page 22
2.1.2 Field texture and estimated clay content......Page 24
2.2.1 Definitions and units......Page 25
2.2.2 Typical values of water-holding capacity......Page 26
2.2.3 Moisture balance calculations......Page 28
2.3.2 Methods of measurement......Page 29
2.3.3 Typical values of hydraulic conductivity......Page 30
2.3.4 Suggested interpretation of saturated hydraulic conductivity rating and its implication for management......Page 31
2.3.5 Unsaturated hydraulic conductivity......Page 32
2.3.7 Key references......Page 33
2.4.2 Total porosity and typical values of bulk density......Page 34
2.4.4 Air porosity......Page 37
2.4.6 Key references......Page 39
2.5.2 Limiting values for penetrometer resistance using a cone penetrometer......Page 40
2.6.1 Aggregate tests......Page 41
2.6.4 Tunnelling susceptibility......Page 43
2.6.7 Field indicators of soil structure decline......Page 44
2.7.1 Water repellence......Page 45
2.7.2 Key references......Page 46
3.1.1 General scheme......Page 48
3.1.3 Engineering characteristics of Unified Soil Classification System groups......Page 49
3.2.2 Liquid limit......Page 53
3.3.1 General interpretations......Page 54
3.3.2 Tunnelling susceptibility......Page 59
3.3.3 Key references......Page 60
3.4.3 Linear shrinkage......Page 61
3.4.5 Coefficient of linear extensibility (COLE)......Page 62
3.5.3 Strength of cohesionless soils......Page 63
3.5.5 Further reading......Page 64
4.2.1 Erosion hazard for water......Page 66
4.2.2 Erosion hazard for wind......Page 67
4.3.1 Estimating general soil erodibility......Page 68
4.3.4 Erosion rates and soil depth......Page 71
4.4.1 Soil erodibility ratings for wind......Page 72
4.4.2 Wind erosion rates – soil flux and erosion loss......Page 73
4.4.3 Key references......Page 74
5.1.2 Measurement of pH......Page 76
5.1.5 Expected rates of acidification......Page 79
5.1.7 Influence of soil pH (water) on nutrient availability......Page 80
5.2.1 Cation exchange capacity (CEC)......Page 81
5.2.2 Exchangeable cations......Page 82
5.2.4 Key references......Page 83
5.3.3 Carbon/nitrogen ratio (C/N)......Page 84
5.3.4 Nitrate (NO3 –)......Page 85
5.3.5 Plant testing......Page 86
5.4.1 Phosphorus in soil......Page 87
5.4.2 Phosphorus requirements based on location and sorption rating of the soil......Page 88
5.4.3 Phosphorus requirements based on Bray test......Page 90
5.4.4 Phosphate sorption......Page 92
5.6 Nutrient levels in plants......Page 93
5.7.1 Organic matter......Page 94
5.8 Nutrients removed in farm products......Page 96
5.9 Salinity......Page 98
5.9.2 Conversion of EC 1:5 to ECe......Page 99
5.9.3 Further conversions......Page 100
5.9.4 Interpretation of test values for salinity......Page 103
5.9.5 Salt tolerant pasture recommendations – southern and central New South Wales......Page 104
5.9.7 Composition of seawater......Page 106
5.10.1 Identifying sodic soils......Page 108
5.10.3 Dispersion, sodicity and salinity......Page 111
5.10.6 Further reading......Page 113
5.11.1 General fertilisers and ameliorants......Page 114
5.11.2 Forms of gypsum......Page 116
5.11.3 Liming materials......Page 117
5.12 General fertility rating of soils in Australia......Page 118
5.13.2 Laboratory analyses......Page 119
5.13.4 Interpreting values for acid sulfate soil tests......Page 120
5.13.6 Further reading......Page 122
6.1.1 Biochemical oxygen demand (BOD)......Page 124
6.1.3 Total phosphate......Page 125
6.2.1 General considerations......Page 126
6.2.2 Sodium adsorption ratio......Page 127
6.3.1 General considerations......Page 130
6.3.2 Key references......Page 134
7.1 Introduction......Page 136
7.2 Levels of heavy metals......Page 137
7.4 Further reading......Page 142
8.2.1 Relative amounts – proportions......Page 144
8.2.4 Soil strength/pressure......Page 145
8.2.8 Chemical concentrations (liquid)......Page 146
8.2.9 Level of exchangeable cations – cation exchange capacity......Page 148
8.2.13 Yields of crops......Page 149
General reading......Page 150
References......Page 151
Index......Page 168