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