The Soil Resource

change is simply described by the rate of income and rate of loss. Our home's energy budget, our firm's inventory, our nation's debt, and humanity's numbers all have accounts that change at rates that are equal to the inputs minus the outputs. Jenny's "system view" of the soil was carried into the fertile fields of Midwestern American prairies from the laboratories of Switzerland in the late 1920s. Jenny's rate equations provided the other paradigm or world view that, I recall, brought us to the threshold of systems ecology as it later evolved in the second half of the twentieth century. As if world renown in the specialties of pedology and soil chemistry were not enough for one lifetime, excerpts below remind us that Hans Jenny has also been a perceptive outdoor field ecologist since his early Alpine expeditions with Braun­ Blanquet in the mid 1920s. Jenny's ecosystem studies in the pygmy forest, a further classic example of a soil-plant system "run down" over hundreds of thousands of years since its origin, continue to occupy some of the vigorous retirement time near his farm in Mendocino County. But each specific, quantitative case study, and each research area conserved (with additional hard work) for further study by future generations, fits into Jenny's coherent world view. It is that view, and its legacies of discovery and of tangible landscape preserves, which we are privileged to share with their originator in this volume.

Inhalt

1. Ecosystems and Soils.- A. Concept of Ecosystem.- B. Soil as an Object of Nature.- C. Soil Colors and Soil Particles.- D. Soil Taxonomy and Classification.- E. Review of Chapter.- References.- A. Processes of Soil Genesis.- 2. Water Regimes of Soils and Vegetation.- A. Soil, a Climostat.- B. Gravitational Potential of Water.- C. Sorptive Potential of Water.- D. Matric Potential of Water.- E. Capillary Phenomena.- F. Osmotic Potential.- G. Summation of Potentials.- H. Movement of Water.- I. Flow of Water through the Ecosystem.- J. Soil Water for Plants.- K. Evapotranspiration and Water Balance.- L. Review of Chapter.- References.- 3. Behavior of Ions in Soils and Plant Responses.- A. Biological Elements.- B. Ions in Rock and Soil Crystals and in Solutions.- C. Exchangeable Ions and Ion Exchange.- D. Ion Currents by Diffusion.- E. Oxidation-Reduction Potentials.- F. Aspects of Plant Nutrition in Soils.- G. Problems of Soil Acidity.- H. Mineral Cycling.- I. Limiting Factor or Performance Equations.- J. Review of Chapter.- References.- 4. Origin, Transformation, and Stability of Clay Particles.- A. Six Common Primary Silicate Minerals.- B. Weathering and Neogenesis of Clays.- C. The Structural Kinship of Micas and Clays.- D. Clay Sequences.- E. Solubilities and Stability Fields of Clays.- F. Clays as Initiators of Organic Evolution.- G. Review of Chapter.- References.- 5. Biomass and Humus.- A. Carbon Fixation.- B. Respiration, the Energy Supplier of Soil Organisms.- C. Vegetation Productivities.- D. Nitrogen Fixation.- E. Soil Organisms as Decomposers and Porositors.- F. Soil Organic Matter and Humus.- G. Nitrogen in Humus and Its Availability.- H. Steady-State Formulations.- I. Review of Chapter.- References.- 6. Soil Colloidal Interactions and Hierarchy of Structures.- A. Flocculation and Deflocculation.- B. Mutual Interactions of Unlike Particles.- B. Peds, Crusts, and Voids.- D. Swelling, Shrinking, and Their Turbations.- E. Review of Chapter.- References.- 7. Pedogenesis of Horizons and Profiles.- A. Transport Considerations.- B. Clay Migration.- C. Mottling, Gleyzation, and Concretions.- D. Podzolization.- E. Laterization.- F. The Pedocal Process.- G. Stone Lines and Stone Pavements.- H. Depth Functions of Organic Matter.- I. Review of Chapter.- References.- B. Soil and Ecosystem Sequences.- 8. State Factor Analysis.- A. Derivation of State Factor Formula.- B. Extended Equation.- C. Commentary to the Formula.- D. Ordination of Ecosystems According to State Factors.- E. Factor Variation.- F. Review of Chapter.- References.- 9. The Time Factor of System Genesis.- A. Nature of Chronosequences.- B. Buildup and Decline of Organic Matter in Chronosequences.- C. Leaching of Carbonates.- D. Clay Formation and Profile Features.- E. Pygmy Forest Ecological Staircase.- F. Chronosequences and Plant Succession Theories.- G. Review of Chapter.- References.- 10. State Factor Parent Material.- A. Conceptual Topics.- B. A Primer of Rock Compositions.- C. Soils Derived from Igneous Rocks.- D. The Serpentine Syndrome.- E. Diversity of Limestone-Derived Soils.- F. Glacial Till Variations.- G. Loess Influx Sequences.- H. Review of Chapter.- References.- 11. State Factor Topography.- A. Points of Compass Orientation.- B. Ridge and Trough Configurations.- C. Toposequences on Slopes.- D. Salt-Affected Soils.- E. Soil Erosion.- F. Review of Chapter.- References.- 12. State Factor Climate.- A. Climatic Indices.- B. Altitude Sequences.- C. The Humus-Climate Paradigm.- D. Precipitation, Base Status, and Carbonate Regimes.- E. Climate and Clay Features.- F. Review of Chapter.- References.- 13. Biotic Factor of System Genesis.- A. Formulation of Biotic Factor Sequences.- B. Partitioning Biotic Factor and Environment.- C. Plant-Controlled Initiation of Ecosystem Genesis.- D. Trees in Forests.- E. Prairie-Forest Biosequences.- F. Animal Activities and Impact by Man.- G. Review of Chapter.- References.- 14. Integration of Factors and Overview of Book.- A. Integration of Factors.- B. Overview of Book.- C. Review of Chapter.- References.- Appendix I. Names of Vascular Species Cited.