Unit Soil Science Lesson 3 Objectives Define aggregate the four components of soil mineral matter organic matter air and water bulk density Describe the basic characteristics of the three soil textures sand silt and clay ID: 1027075
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1. Components and Physical Properties of Soil Unit: Soil Science Lesson 3
2. ObjectivesDefine: aggregate, the four components of soil (mineral matter, organic matter, air and water), bulk densityDescribe the basic characteristics of the three soil textures – sand, silt and clayCreate models of seven soil structures – granular, platy, wedge, blocky sub-angular, blocky angular, prismatic and columnarExplain factors that affect aggregate stabilityList and explain factors that affect soil structureDifferentiate between soil structure and aggregate stabilityExplain what causes soil colorExplain basic soil color indications
3. Soil TextureSoil Particle SizeSand> 2 mmSilt.05mm – 2mmClay<.05mmhttp://www.pdst.ie/sites/default/files/Particle%20Size.jpg
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5. Seven Soil Structureshttp://aces.nmsu.edu/pubs/_circulars/CR667/images/fig2_3.jpg
6. Soil StructureSoil structure is the way in which the individual particles (sand, silt, and clay) are arranged into larger distinct aggregates.Soil aggregates are groups of soil particles that bind together more strongly than to neighboring particlesAggregate stability refers to the ability of soil aggregates to avoid disintegration when disturbed by tillage or erosion. Bulk Density is and indicator of soil compaction and is calculated by the dry weight of soil divided by its volume. The variation in bulk density is due largely to the difference in total pore space
7. Factors that affect…Aggregate StabilityAmount of clayChemical elementsOrganic matterBiological activitySoil StructureOrganic matterSoil organismsTillage Freezing and thawingWater movement
8. Differentiate between Soil Structure and Aggregate Stability
9. Soil ColorCauses of Soil ColorHumus contentIron compounds in the soil Basic Soil Color IndicationsIndicator of different soil typesIndicator of certain physical and chemical characteristicsDue to humus content and chemical nature of the iron componds