• What is soil? Introduction to Soil Science and Soil Resources. by N. G. Juma
• Introduction to soil origin and classification
• Cooperative soil science - tutorial
• Get the Latest Dirt on ... Soils! Soil science for juniors
• Principles of soil science, lecture notes, S. W. Broome
• Soil morphology, classification and mapping, lecture notes, K. McSweeney and S. Grunwald
• Soils of Alberta tutorial

• Soil Quality - the Functional Value and Stability of Soil Resources

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• Raw materials and weathering processes 

• Earth Deposits: A Basis for Creating Landforms and Soil

• Physical and chemical weathering 

• Soil Mineralogy - crystal structures, phyllosilicates 
• Images of clay minerals
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• Soil formation and profile differentiation by S. W. Broome
• The factors of soil formation, (book, pdf, 5 MB) Hans Jenny
• The colour of soil - Munsell system
• Soil structure - NASA
• Soil structure - NRCS
• Soil consistence - NASA
• Soil texture - NASA
• Soil texture, by R. B. Brown
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• Soil and water chemistry, lecture notes, R. G. Burau and R. J. Zasoski
• Soil Humic Substances by Jerzy Weber
• Exchange reactions in soils
• Cation exchange in soils, by S. W. Broome
• Cation exchange capacity and agricultural practice, D.B. Mengel
• Soil acidity and liming by S. W. Broome
• Chemical and physical effects of liming by E.O. McLean 
• Oxidation-reduction reactions in soils
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• Soil physics and soil water, lecture notes, J. W. Hopmans and D. E. Rolston
• Bulk density of soils
• Types of soil water, by S. W. Broome 
• Soil water, lecture notes, New Mexico University
• Soil water movement, by S. W. Broome
• Soil and water - Introduction to irrigation, FAO
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• Soil microorganism and higher plants - N. A. Krasilnikov
• Soil organisms, by S. W. Broome
• Soil biological communities
• Soil biology and soil management
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• Glossary of soil science terms,SSSA
• The Nature and Properties of Soils, 14th edition, Nyle C. Brady • Ray R. Weil - pictures
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• Land and soil degradation assessment, FAO
• Risk assessment methodologies for soil threats
• Soil erosion and erosion control
• Soil and land use, lecture notes, New Mexico University
• Manure and animal waste management
• Urban soils - NCRS

Soil Classification Systems

• World Reference Base for Soil Resources (WRB 1998), FAO, ISSS, ISRIC

• World Reference Base for Soil Resources (WRB 2006), (First update 2007)
• Lecture Notes on the Major Soils of the World. FAO (2001) - pdf (13 MB!!!) or html
• Keys to Soil Taxonomy USDA-NRCS (2006) 
• Soil Taxonomy USDA-NRCS (2002) 
• Soil Classification for Soil Survey by D.G. Rossiter
• Australian Soil Classification

Soil Survey Procedures

• Compendium of On-Line Soil Survey Information by D.G. Rossiter
• Guidelines for soil description. FAO (2006)
• Field Book for Describing and Sampling Soils. USDA-NRCS (2002)
• National Soil Survey Handbook, USDA-NRCS (2002)
• Soil Survey Manual, USDA-NRCS (1993)
• Procedures of soil analysis, L. P. van Reeuvijk, (2002)
• Analytical Methods Manual, Canada, 1984
• Land Evaluation, lecture notes, D. G. Rossiter

Soil Maps and Databases

• World soil maps, FAO
• World soil resources maps, USDA-NRCS
• WRB World map of soil resources 1:25 000 000
• European Digital Archive on Soil Maps of the World
• Harmonized World Soil Database
• Soils of Sveden

• Introduction to Mineralogy, Petrography and Physical Geology. Pamela J. W. Gore

• Introduction to Geomorphology. D. J. Sauchyn

• Introduction to Geology, University of Edinburgh
• Geological time. Dating and timetable

• Geology and Earth Science Terms and Definitions

• The Earth's interior: crust, mantle and core
• The Mohorovicic discontinuity (The Moho)
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• Classification of minerals - mineral families
• The rock cycle. Igneous, sedimentary and metamorphic rocks
• Igneous, sedimentary and metamorphic rocks pictures
• Athena Mineralogy [minerals database, searchable, Switzerland]
• Mineral Pictures by Athena
• Mineral Gallery ['the first internet rock shop' from Amethyst Galleries, USA]
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• Forces That Shape the Surface of the Earth: endogenic and exogenic processes
• Tectonics and Landforms. Important Terms and Concepts
• Plate tectonics: an introduction
• The story of plate tectonics - USGS
• Volcanic activity and lanforms
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• Weathering, Mass movement and Erosion
• Landslide type and processes
• Landslide photo collections - USGS
• The Landslide Handbook - USGS
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• Fluvial processes and landforms
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• Glacial systems
• Retreat of Alaska's Glaciers
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• Eolian processes and landforms
• Types of dunes - USGS
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• Orders of relief
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• GeoGuide
• The Virtual Library: Earth Science, Karlsruhe University 

• Resources of minerals and energy, by S. A. Nelson
• World Mineral Production 2003–2007
• European Mineral Statistics 2003–2007
• Mineral Resources OnLine Spatial Data - USGS
• Origin of ore deposits
• Mining photos
• Alternative Energy Technologies
• Methane Generation From Livestock Waste
• Animal Manure As a Plant Nutrient Resource
• Alcohol distillation from agricultural products and wastes
• Influence of agriculture on environment (air, water, soil); waste management and energy production, Purdue University
• Sustainable Agriculture Research and Education Program, University of California
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• Uses of granite

• The Basics of NMR [an on-line book by Joseph P. Hornak]
• X-Ray analysis of soils and rocks
• Soils under microscope: soil micromorphology, by H. Eswaran
• Particle size distribution determination
• Instrumentation in agronomy, syllabus
• How to make a professional soil monolith model?
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• Online Periodic Table
• International System of Units
• Constants, Units and Uncertainty