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Soil AnalysisObjectives
•To understand how soil is formed•To know the different soil horizons•Be able to characterize soil based on:
• Color•Texture•Structure and •pH
•Be able to identify the type based on its constituent particle size
Soil Constituents: Air Water Nutrients Organic matter Disintegrated rock and Microorganisms
Soil Formation Rate: 1inch/500-1000 years
Soil Erosion: Natural and Anthropogenic Cropland: 1inch/15-30 years (US,1990)
Desertification Soil compaction Overgrazing Depletion of water resources and
Drought Salinization Climate Change
Climate◦ High in warmer and wetter climate
Organisms◦ Microbial decomposition◦ Vegetation
Topographic relief ◦ Mountain/valleys: slope, wind, water, sun
Parent materials◦ Based on geological material
Time
Weathering◦ Physical◦ Chemical◦ Biological
Texture◦ Loam
Mixture of sand, silt and clay◦ Soil Porosity
Sizes of spaces between soil particles Crop production
Characteristics◦ Color (dark, red, white)◦ Structure (aggregated and clumped)◦ pH ( 0-14 acidic, neutral, alkaline)
Soil and nutrients ◦ Nitrogen (N), Phosphorus (P), Potassium (K)◦ Eutrophication
Components
Particle Size
Clay <0.002mm
Silt 0.002-0.05mm
Sand 0.05-2.0 mm
Place soil in top sieve Swirl for about 2 minutes Discard top sieve (sieve #5) Weigh and combine next 2 sieves
◦ (#10 + #60) = sand Weigh 4th sieve (#230) = silt Weigh 5th sieve (bottom)= clay Calculate percentages Use triangle method to determine texture