Agricultural Sciences

  1. Soil Science
    1. Soil Formation and Development
      1. Weathering Processes
        1. Physical Weathering
          1. Temperature Changes
            1. Freeze-Thaw Cycles
              1. Abrasion and Erosion
              2. Chemical Weathering
                1. Hydrolysis
                  1. Oxidation and Reduction
                    1. Carbonation
                      1. Hydration
                      2. Biological Weathering
                        1. Root Action
                          1. Microbial Activity
                            1. Organic Acid Production
                          2. Soil Forming Factors
                            1. Parent Material
                              1. Igneous Rocks
                                1. Sedimentary Rocks
                                  1. Metamorphic Rocks
                                    1. Transported Materials
                                    2. Climate
                                      1. Temperature Effects
                                        1. Precipitation Patterns
                                          1. Seasonal Variations
                                          2. Organisms
                                            1. Vegetation Influence
                                              1. Soil Fauna Activity
                                                1. Microbial Communities
                                                2. Topography
                                                  1. Slope and Aspect
                                                    1. Elevation Effects
                                                      1. Drainage Patterns
                                                      2. Time
                                                        1. Soil Age and Development
                                                          1. Chronosequences
                                                        2. Soil Profile Development
                                                          1. Horizon Formation
                                                            1. Profile Differentiation
                                                              1. Diagnostic Features
                                                              2. Soil Components
                                                                1. Mineral Components
                                                                  1. Primary Minerals
                                                                    1. Secondary Minerals
                                                                      1. Clay Minerals
                                                                      2. Organic Components
                                                                        1. Fresh Organic Matter
                                                                          1. Decomposed Organic Matter
                                                                            1. Humus Formation
                                                                            2. Soil Air and Water
                                                                          2. Soil Physical Properties
                                                                            1. Soil Texture
                                                                              1. Particle Size Classification
                                                                                1. Sand Fraction
                                                                                  1. Silt Fraction
                                                                                    1. Clay Fraction
                                                                                    2. Textural Classes
                                                                                      1. Sandy Soils
                                                                                        1. Loamy Soils
                                                                                          1. Clay Soils
                                                                                          2. Textural Analysis Methods
                                                                                            1. Hydrometer Method
                                                                                              1. Pipette Method
                                                                                                1. Laser Diffraction
                                                                                              2. Soil Structure
                                                                                                1. Aggregate Types
                                                                                                  1. Granular Structure
                                                                                                    1. Blocky Structure
                                                                                                      1. Platy Structure
                                                                                                        1. Prismatic Structure
                                                                                                        2. Aggregate Formation Mechanisms
                                                                                                          1. Physical Binding
                                                                                                            1. Chemical Cementing
                                                                                                              1. Biological Binding
                                                                                                              2. Structure Stability
                                                                                                                1. Wet Aggregate Stability
                                                                                                                  1. Factors Affecting Stability
                                                                                                                2. Soil Density and Porosity
                                                                                                                  1. Bulk Density
                                                                                                                    1. Measurement Methods
                                                                                                                      1. Factors Affecting Bulk Density
                                                                                                                        1. Management Implications
                                                                                                                        2. Particle Density
                                                                                                                          1. Typical Values
                                                                                                                            1. Measurement Techniques
                                                                                                                            2. Porosity Characteristics
                                                                                                                              1. Total Porosity
                                                                                                                                1. Macroporosity
                                                                                                                                  1. Microporosity
                                                                                                                                    1. Pore Size Distribution
                                                                                                                                  2. Soil Color
                                                                                                                                    1. Color Determination
                                                                                                                                      1. Munsell Color System
                                                                                                                                        1. Factors Influencing Color
                                                                                                                                        2. Color Significance
                                                                                                                                          1. Organic Matter Content
                                                                                                                                            1. Iron Oxide Presence
                                                                                                                                              1. Drainage Conditions
                                                                                                                                            2. Soil Temperature
                                                                                                                                              1. Temperature Regimes
                                                                                                                                                1. Factors Affecting Soil Temperature
                                                                                                                                                  1. Temperature Effects on Plant Growth
                                                                                                                                                    1. Management of Soil Temperature
                                                                                                                                                    2. Soil Water Relations
                                                                                                                                                      1. Water Retention
                                                                                                                                                        1. Field Capacity
                                                                                                                                                          1. Permanent Wilting Point
                                                                                                                                                            1. Available Water Capacity
                                                                                                                                                            2. Water Movement
                                                                                                                                                              1. Infiltration
                                                                                                                                                                1. Percolation
                                                                                                                                                                  1. Capillary Rise
                                                                                                                                                                  2. Water Measurement
                                                                                                                                                                    1. Gravimetric Method
                                                                                                                                                                      1. Tensiometers
                                                                                                                                                                        1. Time Domain Reflectometry
                                                                                                                                                                    2. Soil Chemical Properties
                                                                                                                                                                      1. Soil Reaction and pH
                                                                                                                                                                        1. pH Scale and Measurement
                                                                                                                                                                          1. Factors Affecting Soil pH
                                                                                                                                                                            1. pH Effects on Nutrient Availability
                                                                                                                                                                              1. pH Management
                                                                                                                                                                                1. Liming Acid Soils
                                                                                                                                                                                  1. Acidifying Alkaline Soils
                                                                                                                                                                                2. Ion Exchange Properties
                                                                                                                                                                                  1. Cation Exchange Capacity
                                                                                                                                                                                    1. Sources of CEC
                                                                                                                                                                                      1. Measurement Methods
                                                                                                                                                                                        1. Factors Affecting CEC
                                                                                                                                                                                        2. Base Saturation
                                                                                                                                                                                          1. Anion Exchange Capacity
                                                                                                                                                                                          2. Soil Salinity and Sodicity
                                                                                                                                                                                            1. Salt-Affected Soils
                                                                                                                                                                                              1. Saline Soils
                                                                                                                                                                                                1. Sodic Soils
                                                                                                                                                                                                  1. Saline-Sodic Soils
                                                                                                                                                                                                  2. Causes of Salinity
                                                                                                                                                                                                    1. Natural Causes
                                                                                                                                                                                                      1. Human-Induced Causes
                                                                                                                                                                                                      2. Effects on Plant Growth
                                                                                                                                                                                                        1. Reclamation Methods
                                                                                                                                                                                                          1. Physical Amendments
                                                                                                                                                                                                            1. Chemical Amendments
                                                                                                                                                                                                              1. Biological Methods
                                                                                                                                                                                                            2. Soil Organic Matter
                                                                                                                                                                                                              1. Composition and Forms
                                                                                                                                                                                                                1. Active Organic Matter
                                                                                                                                                                                                                  1. Slow Organic Matter
                                                                                                                                                                                                                    1. Passive Organic Matter
                                                                                                                                                                                                                    2. Decomposition Processes
                                                                                                                                                                                                                      1. Mineralization
                                                                                                                                                                                                                        1. Humification
                                                                                                                                                                                                                          1. Factors Affecting Decomposition
                                                                                                                                                                                                                          2. Functions in Soil
                                                                                                                                                                                                                            1. Nutrient Supply
                                                                                                                                                                                                                              1. Soil Structure Improvement
                                                                                                                                                                                                                                1. Water Retention
                                                                                                                                                                                                                                  1. Cation Exchange
                                                                                                                                                                                                                                2. Soil Buffer Systems
                                                                                                                                                                                                                                  1. pH Buffering
                                                                                                                                                                                                                                    1. Nutrient Buffering
                                                                                                                                                                                                                                      1. Buffer Capacity
                                                                                                                                                                                                                                    2. Soil Biology and Ecology
                                                                                                                                                                                                                                      1. Soil Microorganisms
                                                                                                                                                                                                                                        1. Bacteria
                                                                                                                                                                                                                                          1. Heterotrophic Bacteria
                                                                                                                                                                                                                                            1. Autotrophic Bacteria
                                                                                                                                                                                                                                              1. Nitrogen-Fixing Bacteria
                                                                                                                                                                                                                                              2. Fungi
                                                                                                                                                                                                                                                1. Saprophytic Fungi
                                                                                                                                                                                                                                                  1. Mycorrhizal Fungi
                                                                                                                                                                                                                                                    1. Plant Pathogenic Fungi
                                                                                                                                                                                                                                                    2. Actinomycetes
                                                                                                                                                                                                                                                      1. Characteristics and Functions
                                                                                                                                                                                                                                                        1. Antibiotic Production
                                                                                                                                                                                                                                                        2. Algae and Cyanobacteria
                                                                                                                                                                                                                                                          1. Protozoa
                                                                                                                                                                                                                                                          2. Soil Fauna
                                                                                                                                                                                                                                                            1. Macrofauna
                                                                                                                                                                                                                                                              1. Earthworms
                                                                                                                                                                                                                                                                1. Arthropods
                                                                                                                                                                                                                                                                  1. Vertebrates
                                                                                                                                                                                                                                                                  2. Mesofauna
                                                                                                                                                                                                                                                                    1. Springtails
                                                                                                                                                                                                                                                                      1. Mites
                                                                                                                                                                                                                                                                        1. Enchytraeids
                                                                                                                                                                                                                                                                        2. Microfauna
                                                                                                                                                                                                                                                                          1. Nematodes
                                                                                                                                                                                                                                                                            1. Rotifers
                                                                                                                                                                                                                                                                              1. Tardigrades
                                                                                                                                                                                                                                                                            2. Soil Food Web
                                                                                                                                                                                                                                                                              1. Trophic Levels
                                                                                                                                                                                                                                                                                1. Primary Producers
                                                                                                                                                                                                                                                                                  1. Primary Consumers
                                                                                                                                                                                                                                                                                    1. Secondary Consumers
                                                                                                                                                                                                                                                                                      1. Decomposers
                                                                                                                                                                                                                                                                                      2. Energy Flow
                                                                                                                                                                                                                                                                                        1. Nutrient Cycling
                                                                                                                                                                                                                                                                                        2. Soil Enzyme Activity
                                                                                                                                                                                                                                                                                          1. Types of Soil Enzymes
                                                                                                                                                                                                                                                                                            1. Enzyme Sources
                                                                                                                                                                                                                                                                                              1. Factors Affecting Activity
                                                                                                                                                                                                                                                                                                1. Measurement Methods
                                                                                                                                                                                                                                                                                                2. Rhizosphere Ecology
                                                                                                                                                                                                                                                                                                  1. Root-Soil Interactions
                                                                                                                                                                                                                                                                                                    1. Rhizosphere Microorganisms
                                                                                                                                                                                                                                                                                                      1. Root Exudates
                                                                                                                                                                                                                                                                                                    2. Soil Classification and Survey
                                                                                                                                                                                                                                                                                                      1. Soil Taxonomy Systems
                                                                                                                                                                                                                                                                                                        1. USDA Soil Taxonomy
                                                                                                                                                                                                                                                                                                          1. Soil Orders
                                                                                                                                                                                                                                                                                                            1. Suborders and Great Groups
                                                                                                                                                                                                                                                                                                              1. Subgroups and Families
                                                                                                                                                                                                                                                                                                              2. World Reference Base
                                                                                                                                                                                                                                                                                                                1. FAO Classification System
                                                                                                                                                                                                                                                                                                                2. Diagnostic Horizons and Features
                                                                                                                                                                                                                                                                                                                  1. Epipedons
                                                                                                                                                                                                                                                                                                                    1. Diagnostic Subsurface Horizons
                                                                                                                                                                                                                                                                                                                      1. Other Diagnostic Features
                                                                                                                                                                                                                                                                                                                      2. Soil Survey Methods
                                                                                                                                                                                                                                                                                                                        1. Field Survey Techniques
                                                                                                                                                                                                                                                                                                                          1. Soil Mapping Units
                                                                                                                                                                                                                                                                                                                            1. Remote Sensing Applications
                                                                                                                                                                                                                                                                                                                              1. Digital Soil Mapping
                                                                                                                                                                                                                                                                                                                              2. Soil Map Interpretation
                                                                                                                                                                                                                                                                                                                                1. Land Use Planning
                                                                                                                                                                                                                                                                                                                                  1. Agricultural Applications
                                                                                                                                                                                                                                                                                                                                    1. Engineering Applications
                                                                                                                                                                                                                                                                                                                                    2. Land Capability Classification
                                                                                                                                                                                                                                                                                                                                      1. Capability Classes
                                                                                                                                                                                                                                                                                                                                        1. Capability Subclasses
                                                                                                                                                                                                                                                                                                                                          1. Capability Units
                                                                                                                                                                                                                                                                                                                                        2. Soil Fertility and Plant Nutrition
                                                                                                                                                                                                                                                                                                                                          1. Essential Plant Nutrients
                                                                                                                                                                                                                                                                                                                                            1. Macronutrients
                                                                                                                                                                                                                                                                                                                                              1. Nitrogen
                                                                                                                                                                                                                                                                                                                                                1. Forms in Soil
                                                                                                                                                                                                                                                                                                                                                  1. Plant Uptake
                                                                                                                                                                                                                                                                                                                                                    1. Deficiency Symptoms
                                                                                                                                                                                                                                                                                                                                                    2. Phosphorus
                                                                                                                                                                                                                                                                                                                                                      1. Soil Phosphorus Forms
                                                                                                                                                                                                                                                                                                                                                        1. Availability Factors
                                                                                                                                                                                                                                                                                                                                                          1. Management Strategies
                                                                                                                                                                                                                                                                                                                                                          2. Potassium
                                                                                                                                                                                                                                                                                                                                                            1. Soil Potassium Forms
                                                                                                                                                                                                                                                                                                                                                              1. Plant Functions
                                                                                                                                                                                                                                                                                                                                                                1. Deficiency and Toxicity
                                                                                                                                                                                                                                                                                                                                                                2. Calcium
                                                                                                                                                                                                                                                                                                                                                                  1. Soil Calcium
                                                                                                                                                                                                                                                                                                                                                                    1. Plant Functions
                                                                                                                                                                                                                                                                                                                                                                      1. Deficiency Symptoms
                                                                                                                                                                                                                                                                                                                                                                      2. Magnesium
                                                                                                                                                                                                                                                                                                                                                                        1. Soil Forms
                                                                                                                                                                                                                                                                                                                                                                          1. Plant Functions
                                                                                                                                                                                                                                                                                                                                                                            1. Management
                                                                                                                                                                                                                                                                                                                                                                            2. Sulfur
                                                                                                                                                                                                                                                                                                                                                                              1. Soil Sulfur Cycle
                                                                                                                                                                                                                                                                                                                                                                                1. Plant Requirements
                                                                                                                                                                                                                                                                                                                                                                                  1. Deficiency Recognition
                                                                                                                                                                                                                                                                                                                                                                                2. Micronutrients
                                                                                                                                                                                                                                                                                                                                                                                  1. Iron
                                                                                                                                                                                                                                                                                                                                                                                    1. Soil Chemistry
                                                                                                                                                                                                                                                                                                                                                                                      1. Availability Factors
                                                                                                                                                                                                                                                                                                                                                                                        1. Deficiency Management
                                                                                                                                                                                                                                                                                                                                                                                        2. Manganese
                                                                                                                                                                                                                                                                                                                                                                                          1. Soil Forms
                                                                                                                                                                                                                                                                                                                                                                                            1. Plant Functions
                                                                                                                                                                                                                                                                                                                                                                                              1. Toxicity Issues
                                                                                                                                                                                                                                                                                                                                                                                              2. Zinc
                                                                                                                                                                                                                                                                                                                                                                                                1. Soil Zinc
                                                                                                                                                                                                                                                                                                                                                                                                  1. Deficiency Symptoms
                                                                                                                                                                                                                                                                                                                                                                                                    1. Fertilizer Sources
                                                                                                                                                                                                                                                                                                                                                                                                    2. Copper
                                                                                                                                                                                                                                                                                                                                                                                                      1. Soil Chemistry
                                                                                                                                                                                                                                                                                                                                                                                                        1. Plant Functions
                                                                                                                                                                                                                                                                                                                                                                                                          1. Deficiency and Toxicity
                                                                                                                                                                                                                                                                                                                                                                                                          2. Boron
                                                                                                                                                                                                                                                                                                                                                                                                            1. Soil Boron
                                                                                                                                                                                                                                                                                                                                                                                                              1. Plant Requirements
                                                                                                                                                                                                                                                                                                                                                                                                                1. Management Considerations
                                                                                                                                                                                                                                                                                                                                                                                                                2. Molybdenum
                                                                                                                                                                                                                                                                                                                                                                                                                  1. Soil Forms
                                                                                                                                                                                                                                                                                                                                                                                                                    1. Plant Functions
                                                                                                                                                                                                                                                                                                                                                                                                                      1. Deficiency Symptoms
                                                                                                                                                                                                                                                                                                                                                                                                                      2. Chlorine
                                                                                                                                                                                                                                                                                                                                                                                                                        1. Plant Functions
                                                                                                                                                                                                                                                                                                                                                                                                                          1. Soil Sources
                                                                                                                                                                                                                                                                                                                                                                                                                      3. Nutrient Cycling
                                                                                                                                                                                                                                                                                                                                                                                                                        1. Nitrogen Cycle
                                                                                                                                                                                                                                                                                                                                                                                                                          1. Nitrogen Fixation
                                                                                                                                                                                                                                                                                                                                                                                                                            1. Biological Fixation
                                                                                                                                                                                                                                                                                                                                                                                                                              1. Industrial Fixation
                                                                                                                                                                                                                                                                                                                                                                                                                              2. Mineralization
                                                                                                                                                                                                                                                                                                                                                                                                                                1. Nitrification
                                                                                                                                                                                                                                                                                                                                                                                                                                  1. Denitrification
                                                                                                                                                                                                                                                                                                                                                                                                                                    1. Volatilization
                                                                                                                                                                                                                                                                                                                                                                                                                                    2. Phosphorus Cycle
                                                                                                                                                                                                                                                                                                                                                                                                                                      1. Mineralization
                                                                                                                                                                                                                                                                                                                                                                                                                                        1. Immobilization
                                                                                                                                                                                                                                                                                                                                                                                                                                          1. Adsorption and Desorption
                                                                                                                                                                                                                                                                                                                                                                                                                                          2. Potassium Cycle
                                                                                                                                                                                                                                                                                                                                                                                                                                            1. Release from Minerals
                                                                                                                                                                                                                                                                                                                                                                                                                                              1. Fixation and Release
                                                                                                                                                                                                                                                                                                                                                                                                                                              2. Sulfur Cycle
                                                                                                                                                                                                                                                                                                                                                                                                                                                1. Mineralization
                                                                                                                                                                                                                                                                                                                                                                                                                                                  1. Oxidation and Reduction
                                                                                                                                                                                                                                                                                                                                                                                                                                                2. Soil Testing and Analysis
                                                                                                                                                                                                                                                                                                                                                                                                                                                  1. Soil Sampling
                                                                                                                                                                                                                                                                                                                                                                                                                                                    1. Sampling Strategies
                                                                                                                                                                                                                                                                                                                                                                                                                                                      1. Sample Collection
                                                                                                                                                                                                                                                                                                                                                                                                                                                        1. Sample Preparation
                                                                                                                                                                                                                                                                                                                                                                                                                                                        2. Laboratory Analysis Methods
                                                                                                                                                                                                                                                                                                                                                                                                                                                          1. pH and Buffer pH
                                                                                                                                                                                                                                                                                                                                                                                                                                                            1. Organic Matter
                                                                                                                                                                                                                                                                                                                                                                                                                                                              1. Nutrient Extraction
                                                                                                                                                                                                                                                                                                                                                                                                                                                                1. Micronutrient Analysis
                                                                                                                                                                                                                                                                                                                                                                                                                                                                2. Test Result Interpretation
                                                                                                                                                                                                                                                                                                                                                                                                                                                                  1. Calibration Studies
                                                                                                                                                                                                                                                                                                                                                                                                                                                                    1. Correlation with Plant Response
                                                                                                                                                                                                                                                                                                                                                                                                                                                                      1. Recommendation Development
                                                                                                                                                                                                                                                                                                                                                                                                                                                                    2. Fertilizers and Soil Amendments
                                                                                                                                                                                                                                                                                                                                                                                                                                                                      1. Inorganic Fertilizers
                                                                                                                                                                                                                                                                                                                                                                                                                                                                        1. Nitrogen Fertilizers
                                                                                                                                                                                                                                                                                                                                                                                                                                                                          1. Urea
                                                                                                                                                                                                                                                                                                                                                                                                                                                                            1. Ammonium Sulfate
                                                                                                                                                                                                                                                                                                                                                                                                                                                                              1. Ammonium Nitrate
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                1. Slow-Release Forms
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                2. Phosphorus Fertilizers
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  1. Superphosphate
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    1. Diammonium Phosphate
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      1. Rock Phosphate
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      2. Potassium Fertilizers
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        1. Muriate of Potash
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          1. Sulfate of Potash
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          2. Complex Fertilizers
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            1. NPK Combinations
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              1. Micronutrient Blends
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            2. Organic Amendments
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              1. Animal Manures
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                1. Cattle Manure
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  1. Poultry Manure
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    1. Swine Manure
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    2. Compost
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      1. Composting Process
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        1. Compost Quality
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          1. Application Methods
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          2. Green Manures
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            1. Leguminous Green Manures
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              1. Non-Leguminous Green Manures
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              2. Biochar
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              3. Biofertilizers
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                1. Rhizobium Inoculants
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  1. Mycorrhizal Inoculants
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    1. Phosphate Solubilizing Bacteria
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      1. Plant Growth Promoting Rhizobacteria
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      2. Soil Conditioners
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        1. Lime and Liming Materials
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          1. Gypsum
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            1. Organic Matter Amendments

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                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      Go to top

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                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      3. Plant Science