soil lab guiding questions

Download Soil lab guiding questions

Post on 16-Jan-2015




1 download

Embed Size (px)


This presentation covers a complete unit on soil. The unit covers soil formation, horizons, hazards, properties, characteristics, as well as soil nutrients and forest systems


  • 1. Soil Lab NotesImportance, Formation, Properties & Nutrientsjschmied2014

2. *Guiding Questionswrite these down!*Why is soil important?*What is the process of soil formation?*What are hazards to healthy soil &how can these occur?*What nutrients are in healthy soil &what do nutrients provide to plants?jschmied2014 3. Key Soil VocabularyDead Zone an area of a lake, sound or ocean that has very low, or no, oxygen,causing marine life to die.Micro organisms in soil bacteria, fungi & tiny creatures called protozoa. Macroorganisms include worms, insects, etc.Nutrients Chemicals organisms need to get from the environment to build newcells & make internal processes work (like building DNA, digestion, make leaves).Key plant nutrients are NPK or Nitrogen, Phosphorus & Potassium.Organic Matter matter from living or once living plants, animals and othercreaturespH A measure of how acid or basic a solution is. In the pH scale acids havenumbers from pH 0 to before 7 with 0 being the strongest acid. 7 Is pH neutral.Higher numbers, above 7 to 14 pH are basic, with 14 being the strongest base.Soil Erosion constant wearing away (weathering) & transport of the top layers ofthe soil to valleys, rivers, & the oceanSoil Formation creation of soil by breaking down rocks, minerals, & adding water,decaying plants, animals & other once living creaturesjschmied2013 4. Vocabulary (continued)Soil Layers or Horizons - There are 4 layers, or horizons, of soil in the PacNW:Nutrients & water flows, or percolates downward through the layers. Plants take upthe nutrients if able. The rest flows down & sideward to the water table.O layer (also Litter or Humus layer) Upper layer with lots of dead,decaying plants & animals. Living creatures (fungi, bacteria, worms and small insects)consume this layer & return nutrients back to the forest plants roots. Once decayed,the bottom of this layer becomes part of the A layer. Generally darker brownish color.A Layer, or Horizon (also Topsoil) - Layer rich in nutrients, decaying material,& microorganisms. Darker color.B Layer, or Horizon Less humus, less nutrients andless decaying material, buthas more small rocks. Lighter in color..C Layer, or Horizon Rocky, low nutrients , big rocks, part of Earths outer layer.Lighter, can be bedrock color.Soil Sealing Covering of soil by roads, houses, parking lots etc. thus not allowingforests or crops to grow.Weathering breakdown of the outer rocky part of the Earth into smaller particles likesand, clay & mineralsPhysical weathering or breakdown of rocky areas by wind, waves & rock to rockimpactChemical weathering or breakdown of rock by contact with acids & bases.Biological weakening & breakdown of rock by plants, animals and microbes 5. *Why is soil important to all living things? Is a growing medium for plant (food) production Plants provide food and oxygen for animals Provides habitat for billions of animals & decomposers Animals provide food Used by humans for foundations, holding ponds, roads, etc. Acts as water filter, controls water flow & stores water Recycles nutrients, absorbs & neutralizes contaminants Provides most antibiotics used to fight diseases Soil Nutrients wash into sea & fertilize the phytoplankton. Phytoplankton are the basis of all oceanic food chains & makeabout 70% of the worlds oxygen!jschmied2014 6. Soil Makes up the outermost layer of the Earth 7. *Where does soil come from?Soil is formed from rocks and decaying plants and animals. Created by physical, chemical & biological weathering ofrocks. Microorganisms breaking down organic matter in the soil.Average sample composed of: 45 percent minerals 25 percent water 25 percent air 5 percent organic matter.It takes a long time to make soil. can take over 500 years to make 2 centimeters of topsoil.jschmied2014 8. Soil CompositionFigure 1. Soil composition for average soils.WaterMineralsOrganicMatterAir25%25%45%5%matter from living or once living plants,animals and other creatures 9. Physical (mechanical) WeatheringThe breakdown of rocks by physical processes with no change in therocks make up.Creates joints in rocks 10. Chemical Weatheringis the breakdown of rocks caused by a change in the rocks chemical make up 11. Biological Weatheringthe weakening & breakdown of rock by plants, animals and microbes.Plant Roots - can exert stress orpressure on rock. This is abiologically caused physical action.Plant roots or microorganismsproduce organic acids which help todissolve minerals.A Lichen is made of a fungi & an algae. TheFungi release chemicals, breaking down rockminerals. The minerals released from rockare consumed by the algae.jschmied2014 12. Soil FormationWeathering Physical, Chemical andBiological Processes breakdown rock.Erosion Broken down rock is movedby wind, water, or ice. Thisbreaks the rock down more!Deposition Sediment forms.Organic material isadded & soil beginsto form 13. Soil TypesFigure 2. The three main soil types.SandSmall rock &mineralparticles0.5 2 mm SiltThe % of each soil typein a soil sample willdetermine that soilscharacteristicsSmall, finemineralparticles2 50microns ClayVery Smallfine rockparticles< 2microns 14. Side note: Whats an Micron? 15. What are the layers in healthy soil? This is a cut away of aGrassland soil. Itshows the differentoils horizons, or layers Most evolved layer,is the A horizon, orTopsoil. There are 4 soilhorizons on top ofbedrock in this image 16. *What are the layers in healthy soil?jschmied2013 17. *What are hazardsto healthy soil?ErosionSoil SealingPollutionThese degrade the soil.Cutting down forestsPoor Farming PracticesOvergrazingConstructionDust Bowl Video 18. What Caused the Dust Bowl?Dust Bowl Video 19. What Caused the Dust Bowl? US gives each settler 4x moreland to farm Unusual wet weather causedsettlers to think area is goodfor intense cultivation 6x more area becomesfarmed Native grasses holding soilwere removed Severe drought strikes in1930s, not abnormal Wind, dried topsoil, createshuge dust storms Massive erosion! 20. Some solutions to Dust Bowl ProblemsContour Farming Planting WindbreaksReplanting Native Grasses Providing Farmers Expert HelpSome areas have NEVER RECOVERED 21. Extent of Eroded soil Worldwide 22. Soil Erosion is a huge global problemErosion always happens, but we have increased the process by poor land use! 23. Soil SealingCovering soil w/roads, houses, malls, parking lots.etc. 24. OvergrazingToo many animals eating the vegetation! 25. Dead Zone Process.Forming a Dead ZoneNormal situation 26. Aquatic Dead ZonesLow to no Oxygen Water meets oxygen rich waters in the Gulf of Mexico 27. Soil PropertiesSoil needs the propercombination of 3 propertiesto support life good soil structural characteristicsExample: Texture, Clumping, Water holding ability.Biological: plentiful amount of decomposersExample: Bacteria and Fungi ..Chemical: proper chemicals need to be presentExample: Macronutrients (NPK) &Micronutrients (Calcium, Zinc, H2O) & proper pHjschmied2014 28. What nutrients are in healthy soil?Nitrogen pHLeafRootStemPhosphorousPotassiumNutrients Chemicals thatorganisms need to getfrom the environment tobuild new cells & makeinternal processes work(like building DNA,digestion, make leaves).jschmied2013 29. What nutrients doesour forest soil need?Nutrients: 3 key soil nutrients Nitrogen (N), Phosphorous (P), and Potassium (K)pH Acid Base balance Plants need the propersoil pH for best growthpH is a measure of how acidor basic soil or a solution is.jschmied2013 30. Nitrogen (N) LeafGreenerLeavesFastergrowthBetter seedandroot productionjschmied2013 31. Phosphorous (P) RootStronger root growthBetter flower bloomsMakes plants growfaster, less stressjschmied2013 32. Potassium (K) StemIncreases fruit setStronger stalks &stemsDrought resistanceLess disease & insectdamagejschmied2013 33. pH Why is the proper pH important to plants? pH regulates the amount of nutrients that can be in soil. pH 7is Neutral soil. NW Wash soil is 4 to 7 pH. How does this affect Washington forests? Our rainfall & decomposition of leaves & needles make our soilacidic. Only certain plants can stand acidic soils. Conifers (pines, firs, cedars) grow best in acidic soils, thats whywe have mostly conifers in the Pac NW!jschmied2013 34. How do forest plantsget nutrients?Leaf litter, deadfall, and debrisPrimary decay byfungi in PacNWRelease acids &nutrients ( lower pH)Nutrients absorbedby roots fast, leavesoil poorThermalEnergySoil pH SunlightNPK + H20WaterWaterNutrientsto treeNutrientsto soilNPK & Waterjschmied2014 35. How does NW Washington forest soillose key nutrients like NPK? Invasive species Rainfall2. Deforestation3. Soil Erosion by wind and water 36. CO2O2 SunlightNPK + H20WaterWaterNutrientsto treeNutrientsto soilSoil pHNPK & WaterPlants take up valuable nutrients quickly.Rain washes morenutrients out of the soil & lowersthe soil pH (increases acidity)Decaying plants & animalsAdd Nitrogen, Phosphorous andPotassium back into the soil over time.Not enough to replace all nutrients.Phosphorous & Potassium alsocome from the weathering of rocks &minerals in the soil.Nitrogen supply is limited in PacNW.Fungi is the primary decompo