Week 12 Classification of Soils, Soil Erosion and Conservation, Agricultural Methods PDF

Physical Geography: Classifying Soils, Soil Erosion and Conservation, Agricultural Methods 11/18/2024 - 11/20/2024 PROFESSOR PETE PULEO 1 Soil Classification 2 Learning Objectives Describe the current system of soil classification known as the Soi...

Physical Geography: Classifying Soils, Soil Erosion and Conservation, Agricultural Methods 11/18/2024 - 11/20/2024 PROFESSOR PETE PULEO 1 Soil Classification 2 Learning Objectives Describe the current system of soil classification known as the Soil Taxonomy List and summarize the 12 soil orders in the Soil Taxonomy Discuss the regional patterns of soil orders in the US and globally 3  Soil Classification History Until ~1850, soil was thought to be the outcome of weathering bedrock below Russian scholar Vasily Dokuchaev (1843- 1903) demonstrated environmental conditions also played a role https://en.wikipedia.org/wiki/Vasily_Dokuchaev 4  Soil Classification History US soil scientist Curtis Marbut (1863- 1935) heard of Dokuchaev’s work from one of his students Based on this, he developed the U.S. soil classification system, which focused heavily on climate The USDA soon found this to be too simplistic https://historicmissourians.shsmo.org/curtis-fletcher-marbut/ 5 Soil Classification History The USDA revised the soil classification scheme again by defining it using more observable characteristics Diagnostic Horizons – Soil horizons with characteristic color, thickness, texture, etc. Most current system is the Soil Taxonomy which was made in 1975 6  Soil Taxonomy https://www.researchgate.net/figure/Soil-Taxonomy-Categories-in-an- hierarchical-model_fig10_314453325 7 Soil Orders 8  Soil Formation Review https://soillife.org/soil-101/soil-diversity#soil-orders 9 Soil Horizons Review Distinct soil layers 10  Soil Order: Aridisols (Dry) Occur in arid climates Moderately developed (has B horizon) Only farmed if irrigated, commonly grazed https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/aridisols 11 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/aridisols 12  Soil Order: Mollisols (Prairie) Grassland soils of temperate latitudes with thick, organic matter rich, dark A horizon Organic matter from grass B horizons can have calcium carbonate precipitate from evaporation Used to grow corn and wheat https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 13 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/mollisols 14  Soil Order: Alfisols (Forest) Temperate deciduous forest soils with thinner organic A horizons and lots of clay in B horizons Organic matter from leaves Moderately weathered but can support farming when nutrients are added https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 15 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/alfisols 16  Soil Order: Ultisols (Old) Warmer, wetter climate soil with extensive clay in the B horizon Older, more developed, and more acidic Fertility of soils is rapidly depleted if farmed https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 17 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/ultisols 18  Soil Order: Oxisols (Tropical) Soils of the tropics, very warm and wet regions Extremely weathered with iron oxides (red color), low nutrient availability Forest is cut down, burned, then farmed for a few years and repeated https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 19 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/oxisols 20  Soil Order: Spodosols (Boreal) Sandy soils of coniferous forest regions Form in temperate to warm climates Low clay, high oxide, and high humus B horizons and gray mineral rich E horizons Lumbering is common, agriculture less so because of relatively high acidity https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 21 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/spodosols 22  Soil Order: Gelisols (Frozen) Soils in the highest latitude, coldest climates with permafrost Large amounts of undecomposed organic matter (lots of carbon storage) Permafrost feedback (warming -> more decomposition -> more C released as greenhouse gases -> more warming) https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 23 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/gelisols 24  Soil Order: Entisols (New) New soils with no distinct horizons Not tied to a specific climate Common in areas prone to erosion and deposition like steep slopes, floodplains, sand dunes Found where parent materials greatly resist erosion https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/entisols 25 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/entisols 26  Soil Order: Inceptisols (Young) Slightly developed soils with the beginning of a B horizon (no clays) Not tied to a certain climate Common on steep slopes and where parent materials resist erosion https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 27 28  Soil Order: Histosols (Wetland) Soils that are water saturated and high in organic matter, commonly called peat Common in wetlands which occur across many climate regimes Water saturation prevents decomposition and carbon emissions to the atmopshere https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 29 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/histosols 30  Soil Order: Vertisols (Shrink- Swell) Soils that shrink and grow with seasonal rainfall (soil cracks) Very high percentage clay usually from parent material Exist across a range of climates Bad for construction – not a solid base https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 31 https://www.nrcs.usda.gov/conservation-basics/natural-resource- concerns/soils/vertisols 32  Soil Order: Andisols (Volcanic) Soil developed on volcanic ash with weakly developed B horizons Not primarily influenced by climate High organic matter, great at retaining water Fertile and used for farming across many regions https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil- classification 33 34  Soil Orders Summary https://passel2.unl.edu/view/lesson/69c7561e50b3/4 35 Soil Order Distribution 36  Soil Orders and Development https://serc.carleton.edu/kskl_educator/soil_classification/chap_5_explore.html 37 Soil Order Names 38  Contiguous U.S. Soil Map https://www.researchgate.net/figure/Map-of-soil-taxonomic-classification-over- the-continental-USA-using-the-12-US-soil_fig1_308885731 39  Continental Soil Maps Climate Organisms Relief Parent Material Time https://passel2.unl.edu/view/lesson/69c7561e50b3/4 40  Continental Soil Maps Climate Organisms Relief Parent Material Time https://passel2.unl.edu/view/lesson/69c7561e50b3/4 41  Continental Soil Maps Climate Organisms Relief Parent Material Time https://passel2.unl.edu/view/lesson/69c7561e50b3/4 42  Continental Soil Maps Climate Organisms Relief Parent Material Time https://passel2.unl.edu/view/lesson/69c7561e50b3/4 43  Continental Soil Maps Climate Organisms Relief Parent Material Time https://passel2.unl.edu/view/lesson/69c7561e50b3/4 44  Global Soil Map https://passel2.unl.edu/view/lesson/69c7561e50b3/4 45  Soil Order Land Cover https://passel2.unl.edu/view/lesson/69c7561e50b3/4 46  Activity 1 Description Independently answer the following questions: 1) What soil order is most common in WI? Why? 2) What factors likely drives the formation of histosols? 3) On the map, what features could be considered Non-Soil? 4) What CLORPT inferences can you make about areas with Entisols and Inceptisols? https://www.sciencedirect.com/science/article/pii/S0016706112002169 47  Activity 1 Solution 1) What soil order is most common in WI? Why? Alfisols because they are common in deciduous forests and temperate climates, which are common in Wisconsin https://www.sciencedirect.com/science/article/pii/S0016706112002169 48  Activity 1 Solution 2) What factor likely drives the formation of histosols? Presence of water saturated soils indicates wetland/ marsh/bog environments https://www.sciencedirect.com/science/article/pii/S0016706112002169 49  Activity 1 Solution 3) On the map, what features could be considered Non-Soil? Lakes, rivers, bedrock https://www.sciencedirect.com/science/article/pii/S0016706112002169 50  Activity 1 Solution 4) What CLORPT inferences can you make about areas with Entisols and Inceptisols? Poorly developed soil meaning it is likely young and in high relief environments https://www.sciencedirect.com/science/article/pii/S0016706112002169 51 Soil Erosion and Conservation 52 Learning Objectives Describe the process of soil erosion by wind and water Explain how contour farming, strip farming, terracing, waterways, windbreaks, and conservation tillage reduce soil erosion Understand that the misuse of soil reduces soil fertility and pollutes streams 53 Soil Erosion The wearing away and transportation of soil by water, wind, or ice 54 Causes of Soil Erosion 55 Erosion by Rivers 56 Erosion by Wind Dust storms Air pollution 57  Global Soil Erosion Models https://esdac.jrc.ec.europa.eu/themes/global-soil-erosion 58  Impacts of Soil Erosion Reduced vegetation cover and agricultural productivity Increased flooding due to loss of soil water storage Water and air pollution https://blog.ucsusa.org/karen-perry-stillerman/illinois-dust-storm-disaster-is-a- warning-for-agriculture/ 59 Dust Bowl (1930s) Severe drought and excessive farming led to wind greatly eroding soil in the Great Plains Region 60 Dust Bowl Soil Conservation Efforts Financial aid Development of the soil conservation service in the Department of Agriculture 61 Factors Determining Farmable Land Soil Properties: Structure (particle clumping shape), texture (grain size), drainage, nutrients Relief: Slope of the land Climate: Amount and nature of rainfall, temperature, evaporation 62 U.S. Farmable Land 63 Global Farmable Land 64 Soil Conservation Practices Adding organic matter ◦ Improves soil structure ◦ Enhances water and nutrient holding capability ◦ Protects soil from erosion ◦ Supports soil organisms Examples: Leaving crop residues behind after harvest 65 Soil Conservation Practices Avoid excess tillage ◦ Minimizes loss of organic matter ◦ Protects soil surface and structure ◦ Recues erosion ◦ Reduces compaction 66 Soil Conservation Practices Efficient pest and nutrient management ◦ Reduces water and air pollution ◦ Minimize impact to nontarget organisms Examples: Testing and monitoring soils/pests, applying only needed chemicals in the right amount and at the right time/place 67 Soil Conservation Practices Prevent soil compaction ◦ Increases amount of air and water held by soil ◦ Improves organism habitats Examples: Minimize repeated heavy machinery traffic 68 Soil Conservation Practices Keep the ground covered ◦ Reduces erosion ◦ Improves habitats for organisms Examples: Cover crops – Plants grown to cover soil 69 Soil Conservation Practices Diversify crops ◦ Reduces erosion from different root structures ◦ Controls pest populations ◦ Improves biodiversity and ecosystem resilience Examples: Buffer strips 70 Contour Farming Tiling at right angles to the slope of the land Useful on gentle slopes Produces a series of dams that prevent water from flowing down slope Greatly reduces soil erosion and increases water conservation 71 Strip Farming Farming practice for moderately steep slopes Uses alternating strips of different types of crops Minimizes the flow of water reducing soil erosion Typically combined with contour farming 72 Terracing Farming practice for very steep slopes Flat surfaces cut into slopes Reduces soil erosion Expensive and difficult 73 Windbreaks Planting of vegetation to protect bare soil from full strength wind Reduces soil erosion by wind 74 Waterways Depressions of sloping land where water collects and flows off the land Highly susceptible to erosion 75 Conventional vs. Conservation Tillage 76 Conventional vs. Conservation Tillage 77 https://www.ers.usda.gov/data-products/chart-gallery/gallery/chart- detail/?chartId=105042 78 79 80  Activity 2 Description Independently answer the following questions: 1) What is the average annual change in total erosion on cropland in the US from 1982 to 2012? 2) Why do you think this trend exists? 3) List and describe some of the benefits from reduced soil erosion. https://ers.usda.gov/data-products/chart-gallery/gallery/chart- detail/?chartId=94923 81  Activity 2 Solution 1) What is the average annual change in total erosion on cropland in the US from 1982 to 2012? (1.6 - 2.8) / (2012 – 1982) = -0.04 billion tons of soil per year https://ers.usda.gov/data-products/chart-gallery/gallery/chart- detail/?chartId=94923 82  Activity 2 Solution 2) Why do you think this trend exists? More adaptation of conservation tillage practices which reduces uncovered soil duration and percentage https://ers.usda.gov/data-products/chart-gallery/gallery/chart- detail/?chartId=94923 83  Activity 2 Solution 3) List and describe some of the benefits from reduced soil erosion. Preserve nutrient rich topsoil, reduce need for fertilizers, limit sediment load in streams, preserve soil habitat, better crop production, more sustainable land use https://ers.usda.gov/data-products/chart-gallery/gallery/chart- detail/?chartId=94923 84 Agricultural Methods 85 Learning Objectives Define shifting agriculture and labor-intensive agriculture List the advantages and disadvantages of monoculture farming Describe the key issues associated with pesticide use Explain why chemical fertilizers, pesticides, and herbicides are used despite their many issues 86 Shifting Agriculture Cutting and burning vegetation in a small area of forest to release nutrients to soil Allows crops to be grown until nutrients are depleted (2-3 years) Common in tropical areas with nutrient poor soil 87 Labor-Intensive Agriculture Areas with better soils that require a lot of manual labor to till, plant, and harvest crops Machinery can't be used due to cost, location, or need for hand labor 88 Mechanized Monoculture Machines replace human and animal laborers Requires large expanses of somewhat level land Promotes planting a single crop for more efficient farming, known as monoculture 89  Pros and Cons of Monoculture https://www.researchgate.net/figure/Advantages-and-Disadvantages-of- Monocropping-System_tbl1_361052547 90  Soil Nutrients Often in short supply since crops get their nutrients from the soil and they are not returned to the soil, availability influenced by acidity (pH) https://deepgreenpermaculture.com/2020/05/26/soil-chemistry-fundamentals- part-1-understanding-soil-ph-and-how-it-affects-plant-nutrient-availability/ 91 Inorganic Fertilizers Replace soil macronutrients and micronutrients Do not replace soil organic matter, which is good for structure and water retention 92 Fertilizer Use 93 Impact of Nutrient Runoff Nutrients from Midwest flow into Gulf of Mexico Nutrients cause increased phytoplankton productivity Their decomposition leads to lack of oxygen and a dead zone 94 Pesticides Any chemical used to kill or control populations of pests Pests – Unwanted fungi, animals, or plants Weeds – Unwanted plants 95  Pesticide Categories Insecticides – Insects eat crops, spread disease https://agri-route.com/blogs/news/which-pesticide-types-are-used-in- agriculture 96  Pesticide Categories Herbicides – Weeds take up nutrients and water from soil, shade desired crops, and reduce efficiency of harvesting/selling crops https://agri-route.com/blogs/news/which-pesticide-types-are-used-in- agriculture 97  Pesticide Categories Fungicides – Fungi can break down organic matter in crops or be parasitic and weaken crops https://agri-route.com/blogs/news/which-pesticide-types-are-used-in- agriculture 98  Pesticide Categories Rodenticides – Rodents eat crops, spread disease https://agri-route.com/blogs/news/which-pesticide-types-are-used-in- agriculture 99 An Ideal Pesticide 1) Cheap 2) Targeted 3) Breaks down quickly 4) Becomes harmless DOES NOT EXIST!!! 100  Problems with Pesticide Use Persistent - Chemicals that do not break down attach to soil particles and are moved by wind and water https://www.researchgate.net/figure/Persistence-of-Pesticides-in- Soil_tbl2_338281410 101  Problems with Pesticide Use Bioaccumulation – Gaining higher amounts of a substance in the body of an animal over time because they can‘t be eliminated https://www.researchgate.net/figure/Difference-between-Bioaccumulation-and- Biomagnification_fig2_372116596 102  Problems with Pesticide Use Biomagnification – Gaining higher amounts of a substance in the body of an animal as you move up trophic levels https://www.researchgate.net/figure/Difference-between-Bioaccumulation-and- Biomagnification_fig2_372116596 103 Problems with Pesticide Use Pesticide Resistance - eventually pest populations can become unaffected by pesticides because of the genetic differences that may allow some to live and reproduce As the level of resistance increases, a different compound, increased dosages, or more frequent spraying may be needed 104 Problems with Pesticide Use Nontarget Organism Impacts - Most pesticides kill a variety of organisms and not a single, targeted pest Can kill natural predators of pest and be counterproductive 105  Problems with Pesticide Use Human Health Concerns - Can directly poison workers applying pesticides and the public consuming pesticides on food Can produce mutations, cancers, or birth defects https://www.pesticidereform.org/pesticides-human-health/ 106 With so Many Issues, Why are Pesticides Still Used? Greatly increase the amount of food that can be grown The cost of pesticides is offset by the savings from increased yields Save lives when used for insect-borne disease control 107 Activity 3 Description Discuss the following prompts with a partner: 1) Define conservation tillage and provide a few reasons why farmers have been shifting to a conservation tillage approach. 2) How would the use of pesticides change if the environmental costs became a part of the decision-making process? 108 Activity 3 Solution 1) Define conservation tillage and provide a few reasons why farmers have been shifting to a conservation tillage approach. Conservation Tillage – Agricultural approach that involves reduced tilling and increased crop residue. Less fuel use, less time, less soil compaction, improved soil organic matter/water/nutrient retention, reduced soil erosion 109 Activity 3 Solution 2) How would the use of pesticides change if the environmental costs became a part of the decision-making process? Currently, the cost of using pesticides is low (purchasing and labor to apply) compared to the benefits (increased crop yield). However, if the negative health impacts on workers, consumers, and the environment were factored in, using pesticides would become less cost effective. 110  Multiple Choice Practice Qs Take ~ 1 minute to independently think about and write down an answer to the question on the board. Then, turn to a partner and discuss your reasoning for choosing that answer. Write a second answer after you have discussed your thoughts with a partner (its okay to write the same answer twice or change your answer, just be sure to have two answers per question). Finally, we will discuss the correct answer as a class. Be sure to have your name and date on top and hand in before you leave. 111  Question 1 Which soil order is most common in grasslands at temperate latitudes, such as the Great Plains in the United States? A) Mollisols B) Alfisols C) Ultisols D) Inceptisols 112  Solution 1 Which soil order is most common in grasslands at temperate latitudes, such as the Great Plains in the United States? A) Mollisols B) Alfisols C) Ultisols D) Inceptisols 113 Question 2 This soil order lacks a B horizon and is found in many different climates: A) Ultisols B) Entisols C) Oxisols D) Alfisols 114 Solution 2 This soil order lacks a B horizon and is found in many different climates: A) Ultisols B) Entisols C) Oxisols D) Alfisols 115 Question 3 Which of the following methods can be used to control wind erosion? A) Using windbreaks B) Increasing the use of pesticides C) Compacting the soil D) Removing all vegetation 116 Solution 3 Which of the following methods can be used to control wind erosion? A) Using windbreaks B) Increasing the use of pesticides C) Compacting the soil D) Removing all vegetation 117 Question 4 Which soil conservation technique involves digging out flat areas in very steep terrain? A) Contour Farming B) Strip Farming C) Cover Crop Farming D) Terrace Farming 118 Solution 4 Which soil conservation technique involves digging out flat areas in very steep terrain? A) Contour Farming B) Strip Farming C) Cover Crop Farming D) Terrace Farming 119 Question 5 Which of the following is a major advantage of monoculture? A) Increased biodiversity in the farming ecosystem B) Simplified management and harvesting processes C) Enhanced soil fertility through diverse crop roots D) Reduced use of chemical fertilizers and pesticides 120 Solution 5 Which of the following is a major advantage of monoculture? A) Increased biodiversity in the farming ecosystem B) Simplified management and harvesting processes C) Enhanced soil fertility through diverse crop roots D) Reduced use of chemical fertilizers and pesticides 121 Question 6 What is the primary purpose of pesticides in agriculture? A) To kill all organisms B) To control organisms that harm crops C) To increase biodiversity D) To improve soil chemistry 122 Solution 6 What is the primary purpose of pesticides in agriculture? A) To kill all organisms B) To control organisms that harm crops C) To increase biodiversity D) To improve soil chemistry 123