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Soil and Plant Nutrition

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Title: Soil and Plant Nutrition


1
Soil and Plant Nutrition
The Nation that Destroys Its Soil Destroys
Itself - President Franklin D.
Roosevelt
  • Krystal, Caroline, Crystal

2
Abstract
  • It is important to know how to conserve soil in
    order to sustain agriculture. Soil texture and
    composition play an important role in determining
    which soil conditions optimize plant growth. Soil
    particles come in many different forms sand,
    silt, clay, etc. and result from the weathering
    of rocks. The type of soil helps determine the
    fertility of soil the most fertile being loam
    which has pores that are half air, and half water
    allowing for good aeration, drainage, and water
    storage. Inorganic components involve positively
    and negatively charged mineral ions that form a
    soil solution through cation exchange which can
    be absorbed by roots. In cation exchange, cation
    minerals attached to soil particles are displaced
    by H so that the minerals are available for soil
    solution while the H binds to the soil. Cation
    nutrients are better retained in soil than anion
    nutrients because soil particles are usually
    negatively charged. Organic components are mainly
    found within humus, composed of decomposing
    organisms. The humus provides crumbly soil with
    pores that can retain water and aerate soil while
    increasing cation exchange and act as a mineral
    reserve. In order to sustain agriculture, farmers
    use irrigation to provide ample water,
    fertilization to prevent nutrient depletion, pH
    adjustment to maximize growth conditions, erosion
    control to prevent nutrient runoff, avoiding soil
    compaction to ensure pores are not reduced, and
    phytoremediation to detoxicate contaminated
    soils. In conclusion, since soil contains all the
    nutrients necessary for plant growth, it is
    crucial to know various methods to prevent soil
    degradation.

3
Soil a living finite resource
  • Plants absorb nearly all water/minerals from
    upper layers of soil, therefore it is important
    to know how to preserve these layers. ?

4
Soil Texture
  • Texture depends on particle size (sand, slit,
    clay etc.)
  • Particles come from the weathering of rock
  • Soil horizons soil layers (top soil most
    important contains most nutrients/minerals)
  • Water retained by attraction between negatively
    charged soil particles and water molecules
  • Bigger soil particles more surface area for
    water retention
  • Loams most fertile topsoil (poreshalf air/half
    water)

5
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6
Topsoil Composition
  • Inorganic components (minerals)
  • Binding ability (mineral to soil) depends on
    mineral charge (/-)
  • Soil usually (-) therefore bind better with ()
    minerals less leaching
  • Roots absorb minerals as soil solution made by
    cation exchange
  • Cation Exchange process to make soil solution by
    displacing minerals attached to soil with H
  • Cation exchange potential depends on adhesion
    sites and pH levels

7
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9
Topsoil Composition
  • Organic components
  • Includes organisms found in topsoil ? affect
    physical/ chemical soil properties
  • Eg. Worms transport particles and help aerate
    soil
  • Humus is a major organic part of topsoil
  • Creates crumbly soil with pores that can retain
    water and aerate soil
  • Increases cation exchange capacity
  • Acts as mineral reserve

10
Soil Conservation and Sustainable Agriculture
  • If soil is fertilized, crops become renewable
    resource
  • HISTORY LESSON Soil management helped establish
    first modern societies
  • Sustainable agriculture includes different
    farming methods that are conservation minded,
    environmentally safe and profitable!

11
Soil Conservation and Sustainable Agriculture
Irrigation
  • Water is factor in plant growth ? bring water
    from other resources to replenish soil
  • Limitation
  • can destroy freshwater resources,
  • 75 earths water resources used for agriculture
  • Can lead to salinization (salt pile up when water
    evaporates)
  • Drip irrigation requires less water, reduces
    saline

12
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13
Soil Conservation and Sustainable Agriculture
Fertilization
  • Nutrient depletion is major cause of soil
    degradation
  • Add fertilizer (minerals) to replenish soil
  • Organic fertilizers contain decomposing organic
    material (manure, fishmeal, compost, etc.)
  • Must be decomposed into inorganic nutrients that
    roots can absorb
  • Gradual release of minerals, retained for longer
  • Inorganic fertilizers chemical compounds
  • Immediate release of minerals, easily lost by
    leaching
  • Runoff can lead to algal populations oxygen
    depletion

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15
Soil Conservation and Sustainable Agriculture
Adjusting pH
  • Affects cation exchange and chemical form of
    minerals (minerals tightly bound to soil
    minerals in unabsorbable form)
  • Plants prefer slightly acidic soil (more H for
    cation exchange)
  • Difficult to adjust (? one absorption, while ?
    another)
  • pH lt 5, plant absorbs Al3 ? stops root growth,
    stop Ca uptake
  • some plants secrete organic anions to bind to
    Al3 (make it harmless)

16
Soil Conservation and Sustainable Agriculture
Controlling Erosion
  • Major cause of soil depletion (nutrients carried
    away by wind/water)
  • Prevention
  • rows of trees (windbreaker), terracing hillside
    crops, cultivating in contour pattern
  • Other crops good ground cover to protect soil
  • No-till agriculture creating furrows to minimize
    soil disturbance (soil not turned ?fertilizers
    still underground)

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18
Soil Conservation and Sustainable Agriculture
Soil Compaction
  • Soil Compaction squished soil that reduces pores
    less water, absorption, drainage, gas exchange
  • Reduces root growth (hard to penetrate soil)
  • Avoid Soil Compaction
  • Dont farm wet soil,
  • Use lighter equipment

19
Soil Conservation and Sustainable Agriculture
Phytoremediation
  • In industrial areas, toxic substances contaminate
    soil/water
  • Soil remediation detox of contaminated soils
    (REHAB)
  • Usually use nonbiological technologies
    (remove/store toxic soil in landfills) ? costly
    and disrupt landscape
  • Phytoremediation non-destructive biotechnology
  • Use other plants that have high affinity for
    toxic substances to harness those substances
    within the plant thus toxic chemicals removed by
    removing plant

20
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21
In Conclusion
  • Soil properties (ability to retain water and
    minerals) determine the success of plant growth
  • Thus it is important to know various methods to
    conserve soil (especially topsoil) which contains
    the nutrients necessary for growth

22
Bibliography
  • "3. Soil Analysis My Science Box." Welcome to
    My Science Box! My Science Box. N.p., n.d. Web.
    9 June 2010. lthttp//www.mysciencebox.org/soilanal
    ysisgt.
  • Cain, Michael L., Neil A. Campbell, Jane B.
    Reece, Lisa A. Urry, and Steven A. Wasserman.
    BIOLOGY A P Edition. 8 Har/Cdr ed. Columbus
    Pearson, 2007. Print.
  • "New York State Test Prep Social Studies 5 (Grade
    3) People and their Physical Environments."
    studyzone.org. N.p., n.d. Web. 9 June 2010.
    lthttp//www.studyzone.org/testprep/ss5/b/comusanyl
    .cfmgt.
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