frst 201 midterm soil

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nanajun
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240927
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frst 201 midterm soil
Updated:
2013-10-16 14:04:55
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frst soil
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soil
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  1. what is soil?
    a naturally occurring, unconsolidated mineral or organic material at least 10cm thick that occurs at the earth's surface and is capable of supporting plant growth

    a forest soil is any soil that has developed primarily under the influence of a forest cover
  2. why soil is important
    • - medium of plant growth
    • - influences plant species composition and productivity
    • - regulator of water supplies
    • - recycler of raw material/nutrient cycling
    • - soil contaminant reduction
    • - carbon sequestration
    • - habitat for soil organisms
    • - engineering medium
    • - protection of archaeological heritage
    • - source of biochemicals and pharmaceuticals
  3. what are the components of soil
    • Mineral particles
    • air
    • water
    • organic matter (humus, roots, organisms)
  4. types of minerals in soil component
    primary minerals: has not been altered chemically since its deposition and crystallization

    secondary minerals:resulting from the weathering of a primary mineral
  5. minerals that has not been altered chemically since its deposition and crystallization
    primary mimerals
  6. minerals that is resulting from the weathering of a primary mineral
    secondary minerals
  7. what are the impacts of the organic matter in soil component
    • - physical impacts:
    • - chemical impacts
    • - biological impacts
  8. what are the physical impacts of organic matter on soil component
    • - enhances structure       
    • - enhances water holding capacity       
    • - reduces erosion
  9. what are the chemical impacts of organic matter on soil component
    • - improves soil's CEC       
    • - accelerates decomposition of the soil minerals overtime
    • - enhances carbon sequestration
    • - enhances pesticides, heavy metals and other pollutants absorption
  10. what are the biological impacts of organic matter on soil component
    • - provides habitat for microorganisms
    • - enhances soil microbial biodiversity and activity which can help in the suppression of diseases and pests
  11. features of soil water
    • - soup of many dissolved chemicals available for plants and soil organisms
    • - composition varies with time and depth
    • - its acidity or alkalinity determines soil pH which is a master variable of soils
  12. features of soil air
    • - higher humidity (near 100%)
    • - composition changes within local pockets
    • - COis much higher and O2 is lower
  13. physical properties of soil
    • - texture (sand, clay, silt)
    • - structure
    • - porosity
  14. what does soil structure influence? how?
    influences site productivity through its effects on pore size distribution
  15. what impacts does pore size distribution have?
    • - water infiltration
    • - water retention
    • - soil aeration
  16. what are pores in soil?
    voids between soil particles
  17. what influences porosity?
    soil texture and structure
  18. what is coarse texture like?
    • - sandy, soils have larger pores, but less total pore space
    • - rapid water infiltration, low moisture retaining capacity, well aerated
  19. what is fine texture like?
    • - clayey, soils have small pores, but more total pore space
    • - slow water infiltration, high moisture holding capacity, tend to waterlog
  20. what is porosity important for
    root penetration
  21. what is permability
    a measure of how fast air and water can move through a soil

    • granular, single grain --> rapid
    • prismatic, blocky -->moderate
    • massive, platy --> slow
  22. what are soil chemical properties
    • - pH
    • - CEC
  23. how does pH influence soil?
    • - levels of H+ and OH- in the soil influence the solubility of several essential nutrients elements to plants
    • - chemical and biological reactions in the soil
  24. pH range and type of soil
    • pH 10-11: alkali mineral soils
    • pH 6.7-9: arid region mineral soils
    • pH 5-7.5: humid region mineral soils
    • pH 2.5-3.5: peat soils
  25. what is CEC
    • - refers to the number of exchangeable cations that soil solids can adsorb
    • - ability of the soil to hold onto nutrient and prevent them from leaching beyond the roots
  26. CEC is good indicator of ...
    soil fertility, quality and productivity
  27. Factors in soil formation theory
    • - climate
    • - organisms
    • - topography/relief
    • - parent material
    • - time
  28. saturated soil is...
    water retention full, permeability drops
  29. field capacity is ...
    amount of water soil can hold after gravitational water has drained out
  30. wilting point is ...
    minimum amount of water in soil needed to make a plant wilt
  31. types of parent materials
    • - cummulative
    • - residual - saprolite
    • - transported
  32. what are the modes of transportation of parent materials?
    glacier, water, wind, gravity
  33. what is the parent material in Vancouver?
    glacier moraine(till)
  34. climate influence on soil formation (temperature and precipitation)
    - as temperature increases from 0 to 20oC,  clay content % increases exponentially and nitrogen content % decreases exponentially

    - as precipitation increases from 0 to 125cm, clay content % increases
  35. types of humus
    • - mor (L,F,H horizons prominent)
    • - moder (L,F,H horizons prominent)
    • - mull (Ah horizon prominent)
  36. Biota, including plants, animals and micro-organisms, contribute to soil formation by adding organic matter and altering biochemical properties of the profile.
  37. the Time elapsed since the beginning of soil formation controls how far soil development has progressed and how different the soil has become from the underlying parent material.
  38. what are the two major soil horizons
    • Organic
    • Mineral
  39. what are the two steps in soil genesis
    • 1. accumulation of parent material
    • 2. differentiation of horizons
  40. organic horizons in forest floor
    • L - litter
    • F - fermented
    • H - humus
  41. what horizons are in Mor
    • L/F
    • H
    • Ae
    • B
  42. what horizons are in Moder
    • L/F
    • H
    • Ae
    • B
  43. what horizons are in Mull
    • L
    • Ah
    • B
  44. A horizon
    near the soil surface, characterized by processes such as eluviation and/or accumulation of organic matter

    • – Ah – enrichment with organic matter
    • – Ae – eluvial horizon
    • – Ap – mechanically disturbed horizon
    • – Ahe - enriched with organic matter but eluviated
    • – Aej – thin eluvial horizon, weakly developed
  45. B horizon
    characterized by processes such as illuviation of organic matter, clay, Fe/Al oxides

    • – Bh – enrichment with organic matter
    • – Bf – enrichment with Fe/Al oxides
    • – Bhf – characteristics from both h and f
    • – Bt – enrichment with clay
    • – Bn – presence of high % of Na ions. Distinctprismatic structure
    • – Bm – slightly modified by hydrolysis, oxidation, or solution. Has different color, structure or both
    • – Bca – enrichment with secondary carbonates from horizonsabove
    • – Bss – Presence of slickensides (smooth clay coating caused bystress in high clay soils)
    • – Bmk – Slight development and Ca-carbonates present
    • – Bg – gleyed horizon. Gray color and/or mottles
    • – Bx – horizon with fragipan character. Fragipan is loamy withhigh bulk density and low O.M.; when dry seems cemented
  46. C horizon
    limited (or no) alteration through soil forming processes operative in A and B horizons

    • – Ck – presence of Ca-carbonates
    • – Cs – presence of soluble salts
    • – Cg – gleyed horizon. Gray color and/or mottles
  47. BC horizon – transition between B and C,where B dominates
  48. other master horizons
    • W - water layer
    • R - consolidated bedrock
  49. soil order
    dominant soil process
  50. (soil) great group
    Based on the properties that reflect strengths of dominant processes (Humo-ferric Podzol) or a major contribution of a process in addition to the dominant one (Organic Cryosol)
  51. (soil) subgroup
    differentiation on basis of kind and arrangement of horizons that indicate:

    • • conformity to the central concept of the Great group (Orthic Humo-ferric Podzol)
    • • intergrading toward soils of another order (Luvisolic Humo-ferric Podzol)
    • • additional special features (Gleyed SombricHumo-ferric Podzol)
  52. (soil) family
    differentiated based on parent material characteristics

    E.g. Gleyed Sombric Humo-ferric Podzol loamy clay, mixte, slightly alkaline
  53. (soil) series
    based on detailed features of a pedon. Usually from the same area

    E.g. Penticton Orthic Brown Chernozem
  54. three diagnostic horizons
    • - chernozemic A
    • - podzolic B
    • - solonetzic B
  55. Chernozemic A (diagnostic horizons)
    • • Ah >10 cm thick,
    • • 1-17% org. C,
    • • C/N <17,
    • • b.s. >80%, and
    • • Ca2+is dominant cation
  56. Podzolic B (diagnostic horizons)
    Bf, Bhf, Bh >=10 cm thick
  57. Solonetzic B (diagnostic horizons)
    • • Have both Bn and Bnt horizons
    • • Ca exchangeable/Na exchangeable ≤10
  58. 10 soil orders of Canada
    • - Cryosolic order
    • - organic order
    • - vertisolic order
    • - podzolic order
    • - gleyslic order
    • - solonetzic order
    • - chernozemic order
    • - luvisolic order
    • - brunisolic order
    • - regosolic order

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