Presentation on theme: "Nancy Rogel Eddie Guadarrama"— Presentation transcript:
1 Nancy Rogel Eddie Guadarrama Soil ErosionNancy RogelEddie Guadarrama
2 Outline What is Soil Erosion Types of Erosion Factors Affecting Erosion RatesHuman Activities that increase Erosion RatesHow to Prevent Erosion
3 What is Soil ErosionIn agriculture, erosion refers to the removal of a field’s topsoil due to natural forces of water and wind or through human activities such as tillage3 stepsSoil detachmentMovementDeposition
5 Types of Erosion Water Splash Sheet Rill Gully Bank Wind Suspension SaltationSoil CreepGlacialPluckingAbrasionFreeze-thaw
6 Water ErosionSplash Erosion: Direct movement of soil by the impact of water droplets. Soil particles can be thrown up to 3 feetSheet Erosion: Uniform removal of soil in thin layers from a large area due to impact from raindropsRill Erosion: Small channels (<30 cm) carved out on a slope by running waterGully Erosion: Large channels (>30 cm) carved out by running water that cannot be removed by normal tillage equipmentBank Erosion: Saturated sides of running streams fall into moving water below
8 Wind ErosionSuspension: The movement of fine particles into the atmosphere over long distances due to strong windsSaltation: The movement of soil particles through short bounces along the surface, displacing additional particles with each impact. Primary source of wind erosion.Soil Creep: The rolling of larger soil particles across the surface, aided by the bouncing movements of saltating particles
10 Glacial ErosionPlucking: Glacial ice freezes into cracks in rocks and when the glacier moves it pulls out rocks leaving a jagged surfaceAbrasion: When rock frozen to the base and the back of the glacier scrapes the bed rockFreeze-thaw: When water in the cracks of rocks freezes and expands. Over time, portions of rock are broken off
12 Factors Affecting Erosion Rates Climatic FactorsVegetationCharacteristics of SoilTopography
13 Climatic Factors Rainfall Amount, Intensity and Frequency: A greater percentage of the rainfall will become runoff during periods of frequent rainfall.This is due to high soil moisture or saturated conditions.
14 Climatic Factors Temperature: Frozen soil is resistant to erosion Temperature affects organic matter
15 Vegetation Important physical factor influencing soil erosion. Vegetation binds the soil together which makes it more resistant to runoff.Organic matter is provided by vegetation which can slow down runoff.A dense, robust cover of vegetation is one of the best protections against soil erosion.
16 Characteristics of Soil Soil Texture:The size or combination of sizes of individual soil particles.Silt particles are most susceptibleClay or Sand particles are less prone to erosion.
17 Characteristics of Soil Soil Structure:Soil particles get clumped together to form larger clumps and pore spaces.Structure influences both the ability to absorb water and its resistance to erosion.
18 Topography Slope Length: Longer Slope Base of the slope Slope Steepness & Surface Roughness:Speed of runoff flowErosion rates increase if the flow is fast.
19 Human Activities that Increase Erosion Rates OvergrazingOvercroppingDeforestationConstruction
20 Overgrazing Occurs when plants are exposed to intese grazing. Animals can damage the soil surface by eating the vegetation and compacting dry soil with their hooves.Soils with less vegetation become exposed and are more prone to water and wind erosion.
21 OvercroppingThis occurs when the land is being continuously cultivated with no breaks in between crops.Humus Production is affectedThe soil dries out and is prone for wind and rain erosion with less humus.
22 DeforestationDeforestation leaves an open and exposed landscape after cutting down large areas of forests.Nutrients and minerals are removed from the soilAreas are exposed to water and wind erosion.
23 ConstructionConstruction often begins with by clearing the area of any plants or other natural defenses against soil erosion.Construction also includes several tasks such as altering drainage patterns and compacting the soil.
24 How to Prevent Erosion Terracing Contour Farming Cover crops A sloped plane is cut into a series of successively receding flat surfacesContour FarmingPlanes of land are constructed by cutting off the land according to its contours.Cover cropsWindbreaksPlant trees and shrubs along the edges of agricultural fields to help protect the fields against wind erosion.Mixed-croppingCrop rotation