2Soil Categories Topsoil Subsoil Parent Material The upper most layer found in the soil profile.Contains living and non-living material.Animals, bacteria, plants, minerals, soil particles and organic matter.SubsoilSecond layer found in the soil profile.Contains much of the same material as topsoil but lacks the organic matter found in the topsoil.Parent MaterialLast layer found in the soil profile.Made of different rock or plant formationsLimestone, Sandstone, Garnet, and Peat
3Soil FormationSoils are formed from the weathering of the parent materials.There are two types of weathering that affects soils.Physical WeatheringParent material is directly exposed to the weathering affects of the atmosphere.Water, Ice, Snow, Wind, Waves and GravityChemical WeatheringEffects of atmospheric chemicals or biologically produced chemicals on the parent material.
4Soil Makeup Soil is made up of four major components. Sand Silt Clay Minerals
5Soil Makeup Sand Largest of the soil components. Range in size of 2.0 to .05 mm.Drains rapidly.Course in texture.
6Soil Makeup Silt Second smallest of the soil components. Range in size from .063 to .002 mm.Can be a soil, a suspended sediment in surface water, or found on the bottom of a body of water.Moderate drainage.
7Soil Makeup Clay Smallest of the soil components. Formed from chemical weathering of other soil components.Drains very slowly.
8Soil MakeupMineralsThere are 16 nutrients that are essential for plant growth and reproduction that are found in soil.Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Potassium, Sulfur, Calcium, Iron, Magnesium, Boron, Manganese, Copper, Zinc, Molybdenum, and Chlorine.
9Soil EcosystemRelationship between the living and nonliving material found in the soil.An example of this can be found in the Nitrogen cycle
10Land Use Classification Agricultural land can be classified as eight different land capability classes, which determines the final three land use classes.The three land use classes are:Row Crop – used to produce many different agriculture productsPasture – used for the production of grazing animals and forage productionForest – used for the production of trees and wildlife habitat.
11Land Capability Classes The eight land capability classes allow for the classification of the land and their end use.Row CropsClass I – used for row crops with few limitationsClass II – used for row crops with some limitationsClass III – used for row crops with many limitationsClass IV – used for row crops with major limitations
12Land Capability Classes The eight land capability classes allow for the classification of the land and their end use.PastureClass V – areas that are level, but subject to flooding, Used for pasture, grazingClass VI – Limitations prevent row crops, used for pasture
13Land Capability Classes The eight land capability classes allow for the classification of the land and their end use.Forests/WildlifeClass VII – these soils have severe limitations, used for forests and wildlife.Class VIII – these soils have severe limitations used only for forests and wildlife.
14Factors that affect Land Capability There are seven factors that affect the land capability class of a given area.Each of these factors places limitations on the areas for it’s end useSlopeTopsoil ThicknessErosionTopsoil TexturePermeability of the SubsoilDrainageEffective Depth
15Factors that affect Land Capability SlopeThe measured amount of rise or fall on a piece of land over a given distance.Slope is measured over a distance of 25’, 50’ or 100’ and is expressed in percent.Categories of slope Land Use CategoryNearly Level 0-2% Class IVery Gentle 2-5% Class IIGentle 5-8% Class IIISloping 8-12% Class IVStrongly Sloping 12-17% Class VISteep Over 17% Class VII
16Factors that affect Land Capability Topsoil Thicknessis the measured amount of topsoil found on the site. It can be found by measuring down to the color or texture change.Categories of Topsoil Thickness Land UseExtremely Thick Over 40” Class IIIVery Thick 20 to 40” Class IThick 10 to 20” Class IModerate 5 to 10” Class IThin Less than 5” Class II
17Factors that affect Land Capability ErosionThe removal of soil by natural or man made meansErosion is expressed as a percent of the original topsoil which has eroded.Original topsoil thickness 12”Measured topsoil thickness 9”Eroded topsoil = 3”3” of eroded topsoil ) 12” of original topsoil = 25% erosion
18Factors that affect Land Capability ErosionCategories of Erosion Land UseNone to Slight – Less than 25% eroded Class IModerate – 25 to 75% eroded Class IISevere – Over 75% eroded Class III
19Factors that affect Land Capability Topsoil TextureDetermined by the size of the soil particles in the topsoil.Fine - smooth and sticky when wet, particles feel fine as flour. When balled in the palm of your hand, it holds the shape and shows finger marks, a long ribbon of soil can be formed by rubbing the soil between the thumb and fore finger.Medium – medium texture soil is a mixture of sand, silt, and clay particles. It is between fine and coarse. The ball will show some finger marks and hold its shape. A short thick ribbon can be formed.Coarse – coarse textured soil are made up of mostly sand particles. Sand feels gritty and particles are large enough to be easily seen. The ball breaks in your hand and almost no ribbon can be formed.All Topsoil Texture class are land use class I.
20Factors that affect Land Capability DrainageRefers to the surface ad internal drainage. The best clue to soil drainage is color.The color of most subsoils is determined by the amount of iron compound.When the soil is aerated, the iron reacts with the oxygen giving the soil a yellow or red color. In soils that are not well aerated the soils will have a gray color or mottled with gray.The more gray mottles found in the soil profile the slower the drainage.
21Factors that affect Land Capability DrainageCategories of Drainage Land UseExcessively Drained – Course texture, sandy material continues for a depth of 40” Class IIIWell-drained – No gray mottles in top 30” Class IModerately well-drained – No gray mottles in top 20” Class IISomewhat poorly drained – No gray mottles in top 10” Class IIIPoorly Drained – Gray matrix or gray mottles found in top 10”. Soil may be gray completely to the surface Class IVVery wet – Surface water remains for extended periods of time Class V
22Factors that affect Land Capability Effective DepthThe depth that plant roots can easily penetrate. Usually the combined thickness of the topsoil and subsoil, measured to the parent material.Categories of Effective Depth Land UseDeep - Over 40” Class IModerate – 20 to 40” Class IIShallow – 10 to 20” Class IIIVery Shallow Less than 10” Class IV