CONTENTS
Abstract i Resumo ii
Acknowledgements iii
Chapter 1 Soil organic carbon as a proxy indicator of soil quality and sustainability in LNP 1
Introduction 2
Soil organic carbon: legacy data quality, estimation from NIR
spectroscopy and spatial prediction 4
Research aim and objectives 6
Outline of the thesis 6
The research site 8
Chapter 2 Legacy soil data rescue and renewal - a case study of the LNP . 13
Introduction 15
Material and methods 17
Geodetic control 18
Creation of GIS layers 18
Integration of remotely-sensed data and digital elevationmodel 19
Metadata 20
Spatial data infrastructure 21
Inference about SOC stocks 21
2.3 Results and discussion 21
Legacy data archeology ard a brief history of soil resource
inventory in the LNP 21
Selection of legacy soil surveys vicinity 23
Renewal of Legacy survey 26
2.4 Summary and Conclusion 42
Chapter 3 A DSM methodology for poorly accessible area 45
Introduction 47
Material and methods 48
Results and discussion 56
Explanatory variables 56
Strata based on accessibility, similarity analysis 58
Primary data collection and laboratory analysis 61
Development of the spatial prediction model 62
Application of the model in accessible area 68
Model validation in accessible areas 70
Application of the model in poorly-accessible areas 71
Model validation in poorly-accessible areas 72
Relative performance of prediction model in PACC areas 72
3.4 Conclusions 73
Chapter 4 Building a NIR spectral library for the LNP 75
Introduction 77
Materials and methods 78
Soil samples and spectral acquisition 78
Selection of soil samples for reference analysis 79
Laboratory analysis 79
Calibration and validation 80
4.3 Results and discussion 81
Sample selection for reference analysis 81
Soil properties 81
Laboratory SOC vs Landscape units 83
Spectral features 84
Prediction of SOC from NIR spectra 85
Calibration subset models 90
Prediction of SOC from NIR spectra and Clay 90
4.4Conclusions 90
Chapter 5 SOC stocks in the LNP - Amount, spatial distribution anduncertainty 93
Introduction 95
Material and methods 96
5.2.1 Assessing SOC stocks 97
Results and discussion 100
SOC stocks at sampling points 100
Assessing SOC stocks spatial distribution 103
Total SOC stocks estimates and their uncertainty 112
Reliability of SOC stocks estimates and potential
improvements 113
5.4 Conclusions 116
Chapter 6 Synthesis and Conclusions 119
6.1 Synthesis and discussion 120
Renewing legacy soil data for SOC stocks estimation: is it
worth the trouble? 120
Mapping SOC in poorly-accessible areas 120
Near-infrared spectroscopy: a rapid, non-destructive and
environmentally friendly lab method 122
SOC stocks in LNP; amount, spatial distribution and
uncertainty 124
Concluding remarks 125
Recommendations 126
Application of the results of this study 126
Recommendations for further research 127
References 129
Summary 141
Samenvatting 145
Author's Biography 149
ITC Dissertation List 151