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7-4 Soil By Cyndee Crawford September 2014 Soil Table of Contents 28. Chemical Weathering Lab 29. What is a Watershed? / Watershed Demo 30. Groundwater Layers Book 31. Groundwater Notes 32. What is an aquifer? / Surface Water 33. Surface Water 34. Surface Water Examples 35. SOIL profile 36. SOIL composition 37. SOIL texture/particle size 38. SOIL permeability 39. SOIL pH 40. Resources Chemical Weathering Lab p 29 7-4.5 Watersheds Watersheds ● http://www.learn360.com/ShowVideo.a spx?lid=26813561&SearchText=waters hed&ID=1120447 (What is a watershed?) What is a Watershed? / Watershed Demo 1:17 / 9:34 min. Describe what a watershed is. Describe how pollutants enter the water. p 29 7-4.5 Watersheds Watersheds ● Watersheds are surface-water drainage basins. ● Watersheds are important to ecosystems and to human activities. p 29 7-4.5 Watersheds Watersheds ● Water is an important abiotic factor within an ecosystem. ● Runoff - gravity causes some water that falls to the Earth to flow downhill. This is runoff. p 30 7-4.5 Watersheds Groundwater ● groundwater - water that soaks into the ground ● Soil and rock that allow water to pass through are called permeable. ● Create your Groundwater Layers Book p 30 Groundwater Layers Book ● BP: Groundwater o Take notes on layers and components p 31 7-4.5 Watersheds Groundwater ● The water enters the zone of aeration, which is unsaturated. ● Groundwater will keep moving deeper into Earth until it reaches a layer of rock that is not permeable. ● (In other words, water will keep seeping into the ground until it reaches a layer that will not let it pass through. This layer has tightly packed particles.) p 31 7-4.5 Watersheds Groundwater ● The area where the water has filled all the space in the soil is called the zone of saturation. ● The top of the zone of saturation is the water table. p 31 7-4.5 Watersheds Groundwater ● Groundwater can also flow slowly through the underground rock ● or it can be stored in underground layers called aquifers. ● Groundwater is naturally purified as it soaks through the soil layers. Will pollution reach your wells? LAB Making a groundwater model LAB p 32 What is an aquifer? Answer the question: What in an aquifer? p 32 How Does an Aquifer Work? Explain how an aquifer works. p 32 7-4.5 Watersheds Surface-water ● Runoff that has not soaked into the ground is surface-water. ● As runoff travels downhill, it forms the water in streams and rivers. p 32 7-4.5 Watersheds Surface-water ● An area that is drained by a river and all the streams that empty into it, the tributaries, is called a drainage basin or watershed. ● A divide is the high ground between two drainage basins. p 32 What is a meander? Watch this mini video and explain what a meander is. p 33 7-4.5 Watersheds Surface-water ● You can define the watershed area by marking all the tributaries of that river. p 33 7-4.5 Watersheds ● The availability of water as groundwater or surface-water is important to the ecosystems in that area. p 33 7-4.5 Watersheds ● Examples: o o Flowing water can erode the land in one location and deposit the sediments in another. The floodplain of a river may deposit sediment after heavy rains enriching the area with new soil needed for growing vegetation. This new soil is nutrient rich. Crops or natural vegetation grow well in this soil. p 33 What is a Floodplain? Explain what a floodplain is. p 33 7-4.5 Watersheds ● Examples: o o The drainage basin provides the needed water for animal life also. Deltas may form where the river ends its journey into a still body of water like a lake or the ocean. A unique ecosystem forms in delta regions. Ex: the Santee delta in SC or the Mississippi delta in Lousiana p 33 How are deltas formed? Explain how a delta is formed. Stream Table Model LAB p 34 7-4.5 Watersheds ● Water is also important to human activities. ● EX: o Human beings are dependent upon water for survival, not only for drinking, but for agriculture and industry as well. p 34 7-4.5 Watersheds ● EX: o Dams have been placed along some rivers in order to produce hydroelectric power (hydro=water) and to offer recreation in the lakes that form behind the dams. p 34 7-4.5 Watersheds ● EX: o o o Lakes, rivers, and the ocean contain sources of food and minerals. Earth is 71% water with only 3% of that being freshwater (that we drink). Since much of the freshwater on Earth is in the form of ice, very little is left as “usable” freshwater for humans. (That is why we must conserve water.) p 35 7-4.4 Effects of Soil on Ecosystem ● Soil is one of the most valuable abiotic factors in an ecosystem. ● Everything that lives on land depends either directly or indirectly on soil. Soil From Home LAB p 35 BP: Soil Take notes on: ● layers ● components (what soil is made of) ● and more p 35 7-4.4 Effects of Soil on Ecosystem Soil Profile ● Soils form in layers, or horizons, and all the layers make up the soil profile. ● a mature soil profile consists of 3 layers: o topsoil o subsoil o parent material above bedrock p 35 7-4.4 Effects of Soil on Ecosystem Soil Profile ● Topsoil that is nutrient rich, containing a mixture of humus, clay, and minerals, is most suitable for plant growth. ● Most animals live in the topsoil horizon. p 36 7-4.4 Effects of Soil on Ecosystem Composition ● Soil is a mixture of rock particles, minerals, decayed organic material, air, and water. ● The decayed organic matter in soil is humus. ● The sand, silt, and clay portion of soil comes from weathered bedrock material. p 36 7-4.4 Effects of Soil on Ecosystem Composition ● The combination of these materials in soil: o determines the soil type, o affects the types of plants that grow well in it, o & affects the types of animals that can live in it. p 36 7-4.4 Effects of Soil on Ecosystem Composition ● Factors that may affect soil type are: o types of plants o climate o time o slope of the land p 37 7-4.4 Effects of Soil on Ecosystem Texture ● Soil texture depends on the size of the individual soil particles. ● Soil texture is determined by the relative proportions of particle sizes that make up the soil. p 37 7-4.4 Effects of Soil on Ecosystem Texture ● Texture names may include: o loam o sandy clay loam o silt loam o or clay ● The texture name depends on the percent of sand, silt, and clay in the soil sample. p 37 7-4.4 Effects of Soil on Ecosystem Texture ● The texture affects the amount of water that can be absorbed for use by plants and animals. p 37 7-4.4 Effects of Soil on Ecosystem Particle Size ● Soil particles are classified by size ranging from o coarse sand (largest) o to very fine sand (2nd largest) o silt (2nd smallest) o clay (smallest) p 37 7-4.4 Effects of Soil on Ecosystem Particle Size ● Soil particles that are larger than 2mm are called gravel. ● Particle size also affects the amount of water that can be absorbed and used by plants and animals. p 38 7-4.4 Effects of Soil on Ecosystem Soil Quality is based on properties that can be measured, such as permeability and pH. p 38 7-4.4 Effects of Soil on Ecosystem Permeability ● Soil particles have open spaces (pores) between them that let water flow through. ● Permeability - how freely water flows through soil p 38 7-4.4 Effects of Soil on Ecosystem Permeability ● The closer the particles pack together because of particle size, the less permeable the soil is. o Clay particles are small and closely packed, so they have a LOW permeability. (Water does not flow through easily.) o Sand particles are large and loosely packed, so they have a HIGH permeability. (Water does flow through easily.) p 38 7-4.4 Effects of Soil on Ecosystem Permeability ● Measuring permeability involves calculating the rate of drainage. p 39 Soil pH (3:19 min) Soil pH: ● Explain what soil pH is. ● Why is it important? Hydrangeas: ● How can you change the color of the Hydrangea flower? p 39 7-4.4 Effects of Soil on Ecosystem pH ● Soils can be classified as basic or acidic. ● Soils usually measure 4-10 on the pH scale. ● Indicators can be used to measure the pH of soils. p 39 7-4.4 Effects of Soil on Ecosystem pH ● Most plants grow best in soils with of a pH of 5-7. ● If the pH in the soil is not suitable (at the right level), organisms can’t access the nutrients in the soil. ● Lime is a kind of fertilizer that alters pH. ● Lime can make soil more accessible for organisms to get the nutrients they need. Note: This is not the lime you eat. p 40 7-4.6 Renewable or Nonrenewable ● All organisms on Earth, including humans, use resources provided by the environment. ● Earth supplies a variety of natural resources that living things use, change, and reuse. ● Some resources can be replaced and reused by nature; these are renewable resources. ● Natural resources that cannot be replaced by nature are nonrenewable. p 40 7-4.6 Renewable or Nonrenewable Renewable resources are replaced through natural processes at a rate that is equal to or greater than the rate at which they are being used. ● Air, freshwater, soil, living things, and sunlight are renewable resources. ● Air can be cleaned and purified by plants during the process of photosynthesis as they remove carbon dioxide from the air and replace it with oxygen. p 40 7-4.6 Renewable or Nonrenewable Renewable resources ... ● The water cycle allows Earth’s water to be used over and over within the environment. ● Topsoil is formed to replace soil that has been carried away by wind and water (although new soil forms very slowly). ● Trees and other new plants grow to replace those that have been cut down or died. p 40 7-4.6 Renewable or Nonrenewable Renewable resources ... ● Animals are born to replace animals that have died. ● Sunlight, or solar energy, is considered a renewable resource because it will continue to be available for billions of years. o It provides a source of energy for all processes on Earth. p 40 7-4.6 Renewable or Nonrenewable Nonrenewable resources are exhaustible because they are being extracted and used at a much faster rate than the rate at which they were formed. ● Fossil fuels (coal, oil, natural gas), diamonds, metals, and other minerals are nonrenewable. ● They exist in a fixed amount and can only be replaced by processes that take millions of years. p 40 7-4.6 Renewable or Nonrenewable Natural resources can be depleted or used to the point that they are no longer available. ● Conservation measures are necessary for nonrenewable resources because they are known to be in a on-replenishing supply. ● If renewable resources are used at an increasing rate so that they cannot be naturally replaced fast enough, they too can be depleted. p 40 7-4.6 Renewable or Nonrenewable Natural resources ... ● Soil that is lost because it is left bare of vegetation and allowed to erode depletes the land of the fertile topsoil needed for plant growth in that area. ● Depletion of freshwater in an area caused by increased demand by the population living there, by wasteful use of the water, or by pollution, can result in water not being available in needed quantities or being unfit for natural use. p 40 7-4.6 Renewable or Nonrenewable Natural resources ... ● Depletion of a living resource, such as trees being removed without being replanted, can contribute to environmental changes in the land, air, and water in that area. p 40 7-4.6 Renewable or Nonrenewable As the number of people on Earth gets larger, the need for natural resources increases. ● The terms reduce, reuse, recycle and protect are important ways that people can be involved in conservation of natural resources. p 40 7-4.6 Renewable or Nonrenewable ● Reducing involves making a decision to not use a resource when there is an alternative, such as walking or riding a bicycle rather than traveling in a car. p 40 7-4.6 Renewable or Nonrenewable ● Reusing involves finding a way to use a resource (or product from a resource) again without changing it or reprocessing it, such as washing a drinking glass rather than throwing away plastic or Styrofoam. p 40 7-4.6 Renewable or Nonrenewable ● Recycling involves reprocessing a resource (or product from a resource) so that the materials can be used again as another item, such as metals, glass or plastics being remade into new metal or glass products or into fibers. p 40 7-4.6 Renewable or Nonrenewable ● Protecting involves preventing the loss of a resource, usually living things, by managing their environment to increase the chances of survival, such as providing wildlife preserves for endangered animals.