Unit 2: The Earth. Book: Chapter Barron: Chapter 1 Test: October 17/18

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1 Unit 2: The Earth Book: Chapter Barron: Chapter 1 Test: October 17/18

2 Soil - Important because it s a mixture of biological and geological components - It s a medium for plant growth - Filters water - Habitat for living organisms - Filters pollutants

3 Soil formation - Parent rock is weathered and fragments move upward - Organic material accumulates as plants and other organisms die - Greater amount of organic material are present in mature soil

4 Soil formation - Takes hundreds to thousands of years to form - The result of physical and chemical weathering of rocks and gradual accumulation of detritus from the biosphere

5 Soil formation - Factors that determine it - 1) Parent material - the bedrock, what the soil is made from (quartz sandy soil, limestone productive soil with a lot of calcium)

Soil formation - Factors that determine it - 2) Climate - type of climate influences what soil will form( (wind, precipitation/humidity temperature are all part of this) Examples - high latitude

6 Soil formation - Factors that determine it - 2) Climate - type of climate influences what soil will form( (wind, precipitation/humidity temperature are all part of this) Examples - high latitude location where it s freezing, you don t get a lot of soil because you don t have a lot of detritus due to slow decomposition; tropical area will produce a lot of soil, but it s usually acidic due to the rain

7 Soil formation - Factors that determine it - 2) Climate - type of climate influences what soil will form - Precipitation/humidity - Wind -

8 Soil formation - Factors that determine it - 3) Topography - the surface and slope (basically, the landscape). Soils that are on steep slopes are constantly prone to erosion (leading to landslides)...but on the bottom, you get more deposition and a deeper soil

9 Soil formation - Factors that determine it - 4) Organisms nitrogen-fixing bacteria Rhizobium, fungi, insects, worms, snails, etc that decompose litter and recycle nutrients

10 Soil formation - Factors that determine it - 5) Time - the amount of time a soil has spent developing. The longer it s sat around, the more fertile it becomes

Soil horizons - As soil forms, they develop layers (you do need to know the different horizons, their order, and characteristics) - O horizon: organic matter in various stages of decomposition;

11 Soil horizons - As soil forms, they develop layers (you do need to know the different horizons, their order, and characteristics) - O horizon: organic matter in various stages of decomposition; leaves, sticks, animal bodies (where the humus comes from) (sometimes) E horizon: zone of leaching, either beneath O or A, acids go to B layer - A horizon (topsoil): zone of underlying organic material () - B horizon (subsoil): zone of accumulation of metals and nutrients, very little organic - C horizon: (parent materia;): least weathered portion of the soil profile, similar to the parent material, too deep to be eroded, where the soil began!

13 Humus...is not hummus

14 Where do you find a lot of humus? Deciduous Forest (plants and animals decomposing) Grasslands (grasses decompose) Temperate Rainforest (needles/leaves decompose)

15 How does humus improve soil? 1) 2) 3) 4) 5) 6) 7) 8) Provides nutrients (fertility) for plants and soil organisms Increases water holding capacity since it helps topsoil hold more water Makes it easier for roots to grow Provides more soil aeration Improves habitats for soil organisms Prevents erosion Improves soil structure Improves porosity

16 Physical Properties - Texture - what percentage of sand, silt, and clay are there? - Sand (0.05 mm - 2 mm) - Silt (0.002 mm mm) - Clay (<0.005 mm)

17 Soil Triangle /Centricity/Domain/116/Soil %20Texture%20Soil%20Activity.pdf

18 Physical Properties - Porosity - how quickly the soil drains (depends on the texture since it determines the air space) - The amount of water that takes 1 hour in sand - Takes 100 days in silt - And 100 years in clay Loam is the best because it s a mix of all 3

Chemical Properties - Cation exchange capacity - the ability of soil to absorb and release cations like Ca+, Mg2+, Na+, and K+ - Clay particles have a negative charge and cations are held on the

19 Chemical Properties - Cation exchange capacity - the ability of soil to absorb and release cations like Ca+, Mg2+, Na+, and K+ - Clay particles have a negative charge and cations are held on the surface until released and used by plants as nutrients - The overall CEC is a function of types and amounts of clay (more than 20% clay, it holds onto the water, and irrigation leads to waterlogging, or drowning of plants)

20 Chemical Properties - Bases - Calcium, magnesium, potassium, and sodium - They neutralize H and Al - Promotes plant growth (why putting egg shells on plants helps)

21 Chemical Properties - Acids - Aluminum and hydrogen - Detrimental to plant growth - Adding limestone will decrease the acidity

22 Chemical Properties - Base Saturation - Proportion of soil bases to soil acids - A soil with a high CEC and high base saturation tend to be productive

23 Chemical Properties - Base Saturation - Proportion of soil bases to soil acids - In agriculture: a soil with a high CEC (allows it to hold onto the nutrients) and high base saturation (a lot of nutrients) tend to be productive

24 Biological properties of soil - Organisms found in soil - Bacteria, fungi, protozoans, rodents, and earthworms

26 Soil Degradation - Humans have done a lot of degradation to soil, due to agriculture and clearing areas for development - Through agriculture (dredging the soil, planting on it, removing the crops, and repeating), nutrients are depleted - Why is nothing growing? you re using the same soil, and you took away the trees so there aren t roots to hold onto the soil and protect from erosion

27 Erosion - Physical removal of rock fragments from a landscape or ecosystem (basically, taking that rock and moving it somewhere else) - Wind, water, ice, and living organisms can do this - Deposition is the accumulation or depositing of eroded material such as sediment, rock fragments, or soil

28 Erosion - Destroys the soil profile - Increases soil compaction - Decreases the water holding capacity (which creates a positive feedback loop with more erosion) - Crops suffer from water shortage - Low precipitation leads to droughts

29 Poor agricultural techniques Erosion - Monoculture - Cultivation of one crop in an area; depletes nutrients and doesn t allow for time to reconstitute

30 Poor agricultural techniques Erosion - Row cropping, improper plowing, and removing crop wastes all disturb the soil and removes roots/root hairs

31 Poor agricultural techniques Erosion - Overgrazing (removes vegetation and the roots don t hold onto the soil)

32 Types of Erosion - 1) Sheet Erosion - soil moves off as a horizontal layer

33 Types of Erosion - 2) Rill Erosion - fast-flowing water cuts small channels in the soil

34 Types of Erosion - 3) Gully Erosion - extreme rill erosion

35 Effects of Erosion - Damages agriculture, waterways, and infrastructures - Hurts wetland ecosystems, reproductive cycles (like salmon), oxygen holding capacity of water, and the ph of water

Desertification - Productive potential of arid or semiarid land falls by at least 10% due to human activity or climate change - Results in loss of vegetation, increased wind

36 Desertification - Productive potential of arid or semiarid land falls by at least 10% due to human activity or climate change - Results in loss of vegetation, increased wind erosion, salinization, drop in water table, reduced surface water - Fixed by reducing overgrazing, deforestation, destructive planting, irrigation, and mining. Plant trees and grass!

Salinization - Water is not absorbed into the soil and evaporates, leaving behind dissolved salts in the topsoil - Results in stunted crop growth, lower yield, destruction of

38 Salinization - Water is not absorbed into the soil and evaporates, leaving behind dissolved salts in the topsoil - Results in stunted crop growth, lower yield, destruction of plant life - Fixed by delaying production, installing underground perforated drainage pipes, flush soil with fresh water into separate lined evaporation ponds, use halophytic plants

Waterlogging - Saturation of soil with water resulting in a rise in the water table - Results in a decrease of oxygen in the soil, saline water enveloping deeps roots and killing the plants, lower

39 Waterlogging - Saturation of soil with water resulting in a rise in the water table - Results in a decrease of oxygen in the soil, saline water enveloping deeps roots and killing the plants, lower productivity and increasing destruction of plant life - Fixed by a switch to less water-demanding plants in areas susceptible to waterlogging, utilize conservation-tillage farming, plant trees with deep roots, stop production, install pumping stations with drainage pipes that lead to catchment-evaporation basins

40 Climate Change Effects on Soil - Increased global temperatures and decreased precipitation causes desertification - Increased temperatures lead to evaporation of irrigation water, resulting in soil salinization - Increased erosion and/or leaching can result from increased precipitation in certain areas - Increased temperature can lead to faster breakdown of organic matter (so, less organic matter in the soil) -

41 Climate Change Effects on Soil - Increased temperature and shifting climatic belts result in longer growing seasons which can deplete nutrients from the soil - Rising sea levels can result in flooding of coastal areas, leading to salinization of soil and increased soil erosion - Increased temperatures can lead to soil desiccation

42 Review - Describe how climate factors will affect soil formation - Define desertification, salinization, and waterlogging - Describe ways climate change affect soil degradation.

Dust Bowl - 1930s, Oklahoma, Kansas, and Texas - Caused by plowing prairies that caused the loss of natural

43 Dust Bowl s, Oklahoma, Kansas, and Texas - Caused by plowing prairies that caused the loss of natural grasses that rooted the soil - Droughts and winds blew most of the topsoil away, causing the need to evacuate the area

44 1935 Soil Erosion Act - Resulted from the Dust Bowl - Established the Soil Conservation Service - Mandates the protection of the nation s soil reserves, deals with erosion issues, carries out soil surveys, and does research on soil salinity

45 1937 Soil & Water Conservation Act - Provides for a continuing appraisal of U.S. soil, water, and related resources, which includes fish and wildlife habitats - Establishes a soil and water conservation program to assist landowners and land users in furthering soil and water conservation

46 Random things

Inorganic (mined from mineral deposits or synthetically manufactured) Organic (Animal manure, green manure, compost) Pros Cons - Cheap - immediate effect - easy to understand - Doesn t add humus, so

(N and P) - Uses a lot of energy to produce, transport, and apply - Releases nitrous oxide, a greenhouse gas - Usually water soluble, which leads to leaching and groundwater contamination - can throw

47 Inorganic (mined from mineral deposits or synthetically manufactured) Organic (Animal manure, green manure, compost) Pros Cons - Cheap - immediate effect - easy to understand - Doesn t add humus, so result in less ability to hold water and support living organisms - Lowers oxygen content which decreases the amount of fertilizer taken up efficiently - Supplies only a limited number of nutrients (N and P) - Uses a lot of energy to produce, transport, and apply - Releases nitrous oxide, a greenhouse gas - Usually water soluble, which leads to leaching and groundwater contamination - can throw off ecosystems - Improves soil texture, adds organic nitrogen, and stimulates beneficial bacteria and fungi - prevents erosion - Adds micronutrients that are generally insoluble and are broken down slowly by bacteria - Use of microbes mean they work seasonally - Effect may not be immediate since it works according to nature s rules

48 Acid Deposition ( Acid Rain ) Emissions of sulfur and nitrogen compounds are transformed by chemical processes in the atmosphere and deposited back in earth in wet or dry form

49 Effects of Acid Deposition on Soil 1. Increases acidity outside of optimum range and reduces buffering capactiy, resulting in damage to the root systems, poor growth or death 2. Can leach cations/metals/nutrients from soil, decreasing growth since they re not available 3. Releases aluminum which can be toxic to plants 4. Sulfur and nitrogen, while a little fertilizes the soil, can built up to toxic levels for plants

50 Landslides and Mudslides - Landslides - masses of rock, earth, or debris move down a slope (happen after a disturbance in the natural stability of the slope)

51 Landslides and Mudslides - Mudslides (aka mudflows, debris flows) - a landslide down a channel(happen when there is a rapid collection of water that leads to a surge) - Common in areas with wildfires, construction, previous landslides, steep slopes/canyons, channels, directed surface runoff

52 The Rock Cycle - The constant formation and destruction of rock - Made up of sedimentary, metamorphic, and igneous rock - Why it s so hard to find really old rocks! (oldest is in Australia, 3.7 bya)

53 Igneous Rocks - Born of fire they come from magma (when it cools, it hardens to form rock) - Two types: intrusive and extrusive - Intrusive rocks are the large crystals because they cooled sloooowly within the earth (contınental granıte crust) - Extrusive rocks cool fast above the earth, so they have small, grainy, or no crystals (lava rocks - they get shot out of a volcano) (basalt oceanıc crust)

through natural minerals dissolved in water - Organic - Coal - Coquina

55 Sedimentary Rocks - Formed from different types of rock basically glued together they get squished by overlying layer and then cemented together through natural minerals dissolved in water - Organic - Coal - Coquina (ocean organism shells) - Chemical - Water evaporated and left behind rock

56 Metamorphic Rocks - Rocks subjected to high temperature and pressure - Minerals get realigned and you create a new rock

58 Latitude & Longitude

59 What causes seasons?

60 Seasons, Solar Intensity, and Latitude -

4/23/2018. Soil John Wiley & Sons, Inc. All rights reserved. Lecture 14

4/23/2018. Soil John Wiley & Sons, Inc. All rights reserved. Lecture 14 Lecture 14 Soil Lecture 14 1. The Soil System 2. Soil Properties and Major Soil Types 3. Environmental Problems Related to Soil 4. Soil Conservation and Regeneration 1 The Soil System Soil Uppermost layer