2 Soil – a loose mixture of small mineral fragments and organic material Bedrock to SoilSoil – a loose mixture of small mineral fragments and organic materialBedrock – layer of rock beneath the soil;this layer has never been weathered
3 Sources of SoilParent rock is the rock that is the source of the soil.The soil made from granite ( ) will look differently than the soil made from limestone ( )Parent RockParent Rock
4 Sources of SoilResidual soil- soil that remains above the bedrock from which it is formedTransported soil – soil that is blown or washed away( ) from its parent rockErosion
5 Sources of SoilHumus – very small particles of decayed plants and animal material; also known as the organic part of the soil
6 Soil LayersSoil layers are also known as horizons.
7 Horizon ‘0’Contains fresh or decaying organic material (leaves, plants, animals) known asForest soil =Desert soil =Humus.ThickThin
8 Soil LayersLeaching – Rainwater from the surface travels down through the horizons; it dissolves minerals and nutrients, and other substances from the soil above.
9 Soil and Climate TROPICAL CLIMATES CLIMATE - Air is humid and the land receives a lot of waterLeaching occurs quickly and constantly, producing a thin topsoil layer.
10 Soil and Climate DESERT CLIMATES CLIMATE - Very dry and very little rainWater evaporates quickly, causing the soil to have large concentrations of salts, which can produce toxic soil (even to desert plants)EX: Death Valley
11 Soil and Climate TEMPERATE CLIMATES CLIMATE - Enough rain and varying temperaturesThick and fertile soil develops due to the abundance of chemical and mechanical weathering.EX: United States
12 Soil and climate ARCTIC CLIMATES CLIMATE - Little precipitation and extremely cold temperaturesSoil formation occurs slowly due to cold temperatures; the topsoil is extremely thin and unable to support most plants.
13 What do you remember?The source of mineral fragments in soil is called the ______________.The organic part of soil is called ___________.The soil horizon that contains only humus is called _______________.Soil that remains above the bedrock from which it is formed is called _____________.
14 What do you remember? (cont.) Describe the topsoil in the desert climates and in temperate climate.What climate in the United States is called the “breadbasket” for the many crops the region’s soil supports?What do you find at the different horizons or what is another name?Horizon AHorizon BHorizon CHorizon R
15 AnswersThe source of mineral fragments in soil is called the ______________.Parent rocksThe organic part of soil is called ___________.HumusThe soil horizon that contains only humus is called _______________.Horizon OSoil that remains above the bedrock from which it is formed is called _____________.Residual Soil
16 AnswersDescribe the topsoil in the desert climates and in temperate climate.Desert – thin and saltyTemperate – thick and fertileWhat climate in the United States is called the “breadbasket” for the many crops the region’s soil supports?Temperate Climate
17 Answers What do you find at the different Horizons? Topsoil Subsoil Horizon AHorizon BHorizon CHorizon RTopsoilSubsoilPartially weathered RockBedrock
19 Soil ConservationConsists of the various methods by which humans take care of soil
20 Review! Humus Soil takes a long time to grow! Is the part of soil made up of decayed parts of once-living thingsIt is dark and softSoil takes a long time to grow!It takes 500-1,000 years to grow 1 inch of soilDeep soil takes thousands of years to form
21 Layers of Soil Topsoil Subsoil Bedrock The top layer Made of the smallest grainsRichest layer of soil due to the having the most humusSubsoilLayer under topsoilLarger grainsLess humusBedrockSolid rock under soilWeathering breaks down rock into soilMade of different minerals
22 Importance of SoilSoil contains the minerals that all living things need!
23 What Did We Learn? There are many types of soil Soils are made from different mineralsSoils have different colors and different sized grainsSoils can hold different amounts of waterSoils that are best for plants have the right mixture of minerals and humus
25 Soil FactsSoil is an important resource just like water, air, trees, and minerals.If the same type of crop is grown in soil for many years on the same land it could harm the soil.Plants use up the nutrients in the soil, then the soil is too poor for growing more crops.
26 Why is Soil so Important? Minerals and nutrients for plantsHousing for many organisms (earthworms, spiders, moles, prairie dogs)Storage- Soil stores water
27 Saving SoilResource: a material found in nature that living things useConservation: saving resources by using them carefully
28 How Can Soils Be Harmed? Examples of how soil can be harmed: 1. Cutting down trees2. Over-farming3. Erosion- wind and water transport soil and sediment
29 Ways to Save the Soil 1. Strip cropping 2. Contour plowing 3. Crop rotation4. Cover crop
30 Ways to Save the Soil1. Strip cropping: planting strips of thick grass or clover between strips of crops2. Contour plowing: planting rows of crops around the sides of hills (across the slope of a hill) instead of up and down
31 Ways to Save the Soil3. Crop rotation- In order to prevent nutrient depletion, crops planted in certain areas are changed year to year4. Cover crop- a crop that is planted between harvests to reduce soil erosion and to replace certain nutrients in soilEx: Clover and soybeans
32 What Did We Learn?Growing the same type of crop on the same land for many years removes minerals.When people remove plants and trees, soil may be washed away.Farmers conserve soil