Basic Soils

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Basic Soils

• Northeast Texas
• Master Gardener Training

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Soil

• Is
• Dynamic
• always changing
• Alive
• fauna and flora
• Complex
• combination of living, dead, mineral materials
• Nothing short of amazin!!
• Alright, Im a nerd.

• Is not
• Static
• Dirt
• dirt is soil in the wrong place
• Potting soil
• growth medium
• Sand
• silicon is chemically inactive

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Soil Composition

• Constantly changing
• Mineral
• rock derivative
• Pore space
• water
• air
• Organic Matter
• plant and animal matter
• living and dead

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Soil Profile

• Surface A horizon
• Active
• biological
• plant/animal activity
• chemical
• organic matter accumulation
• Subsurface E
• Pan formation
• nutrient mining
• Subsoil B
• Low OM
• Clay accumulation (B2t)
• Subsoil acidity
• Parent Material

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Physical Properties of Soils

• Color
• Texture
• Structure
• Drainage
• Depth
• Surface features

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Soil Color

• Determining factors
• Organic Matter
• Drainage Condition
• Oxidation
• Indications
• Red-Brown
• Good drainage
• Yellow
• fair drainage
• Grey to Dark
• poor drainage

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Texture

• Particle size
• Properties
• Drainage
• SandgtSiltgtgtgtClay
• Water Holding Capacity
• ClaygtgtSiltgtgtgtSand
• Water availability
• SiltgtClaygtSand
• Fertility
• ClaygtSiltgtgtgtSand
• Workability
• SandgtSiltgtClay
• Classes
• Textural groups
• Textural classes

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Texture Determination

• Particle size composition
• Feel method
• Form a Ribbon
• mix water soil (1 tblspn) ball
• press between thumb and forefinger
• Signs
• sand gritty
• silt slick, talcum powder
• no ribbon sand, loamy sand
• lt1 sandy loam, loam, silt loam
• 1-2 silty clay loam, clay loam
• gt2 clay
• Volumetric
• accurate, slow, costly

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Textural Relationships
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Soil Structure

• Soil Aggregate (ped) formation
• Organic matter driven
• Traffic impacted
• Long term development
• Pore space development
• Air flow
• root breathing
• Regulates water
• infiltration rate
• root penetration
• drainage

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Soil Structures
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Soil Depth
Factors - bedrock - water table -
compaction - subsoil pH - nutrient
stratification
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Soil Organic Matter

• Composition
• Carbon Cycle
• living and dead
• plant and animal
• dynamic system
• Advantages
• Improves structure
• increased infiltration
• increased water holding capacity
• increased workability
• increased CEC
• OM has high number of exchange sites
• Increase to 3-4 OM in Northeast Texas under
  perennial pastures

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Chemical Properties

• Soil pH
• Cation Exchange Capacity
• Organic matter content
• Clay mineralogy
• Essential Plant Nutrients
• Nutrient Movement
• Root/soil interaction

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Cation Exchange Capacity

• Natural Fertility
• Exchange sites
• Organic matter
• Clay
• Edge charges
• other materials
• Function
• Attracts Cations
• Repels Anions

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Liebergs Law of Limits

• Crop yield
• barrel water
• Yield limitations
• shortest stave
• 2000 water
• fertilize to match limitations
• over fertilize lost
• under fertilize lost yield
• proper fertilizer matches water limitation

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Soil Fertility

• Physical
• Texture
• Structure
• Infiltration rate
• Utility
• Aesthetics
• Crop selectivity

• Chemical
• Soil pH
• Essential Nutrients
• Macro
• Nitrogen
• Phosphorus
• Potassium
• Secondary
• Micronutrients
• Beneficial Nutrients

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Soil pH

• pH log (H)
• limits nutrient availability
• Crop tolerance highly variable
• Al toxicity apparent before low pH affects plant
  survival
• preferred pH 6-7
• Ryegrass/small grains pHgt5.8
• Clovers pH specific

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Sixteen Essential Nutrients

• CHOPKNS CaFe Mg B Mn CuZn MoCl
• Primary
• C, H, O
• Macronutrients
• N, P, K
• Secondary Nutrients
• Ca, Mg, S
• Micronutrients
• B, Cl, Cu, Fe, Mn, Zn, Mo
• Beneficial
• Na, Ni, Si, Co

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Primary Nutrients

• Function
• Cell Wall formation
• Basic building blocks
• Electron Transfer
• Carbon, Oxygen
• Plant available form
• Plant takes in CO2
• Plant gets O2 from roots
• Hydrogen
• Plant available form H2O
• Releases O from water

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Nitrogen (N)

• Most responsive fertilizer nutrient
• especially grasses
• Absorbed as NO 2, NO3, NH4
• Very Mobile in both plant soil
• Function
• major component of plant chemicals amino acid,
  etc.
• Excess
• excess vegetative growth, limited fruits
• Deficiency
• limited growth, chlorosis, symptoms on old growth
  first
• Notes
• Changes form rapidly in the soil
• N soil tests have little value

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Phosphorus (P)

• Plant available forms
• HPO4-2, H2PO4-
• Fertilizer form H2PO5
• Plant mobile, Soil immobile
• Functions
• ATP, ADP energy, germination, most aspects of
  plant growth
• Excess
• micronutrient deficiency of Zn, Fe and/or Co
• Deficiency
• Reduced plant growth, purpling or browning in
  foliage
• Notes Fixes readily with cations, pH dependent
  solubility

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Potassium (K)

• Plant available form K
• Fertilizer form K2O
• Plant and soil mobile
• Function
• enhances fruit and flower, co-enzyme for TNC
  storage, water balance
• Excess
• causes N deficiency, interferes with other cation
  uptake
• Deficiency
• limited growth, shortened internodes, brown leaf
  edges (margin scorch), wilting
• Notes
• High demand in East Texas Soils. Critical for
  winter survival of perennials.

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Calcium (Ca)

• Plant available form Ca2
• Plant immobile, very limited soil mobility
• Functions Cell membrane integrity, co-enzyme
• Excess
• Mg uptake interference
• Deficiency
• Inhibited bud growth, root tip death, mature leaf
  cupping, weak growth, blossom end rot and pits on
  fruits
• Notes
• Usually corrected with pH, Water stress affects
  Ca relationships.

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Magnesium (Mg)

• Plant available form Mg2
• Plant mobile, limited soil mobility
• Functions
• Chlorophyll compound, co-enzyme, seed germination
• Excess
• Ca uptake interference
• Deficiency
• Growth Reduction, marginal chlorosis, interveinal
  chlorosis in mid and lower leaves, reduced seed
  production, cupped leaves
• Notes
• leaches with irrigation, usually corrected with
  Lime in fields, chelates and sulfates in pots

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Sulfur (S)

• Plant available form SO4-
• Plant immobile, very soil mobile
• Functions
• structural compound of AAs, etc. and chlorophyll
  production
• Excess very limited information
• Deficiency
• Rarely deficient due to pollution and impurities
  symptoms include growth reduction, overall
  chlorosis
• Notes
• leaches with irrigation, usually corrected with
  other nutrients, true toxicity is rare and
  difficult to control, very high levels in low pH
  soils

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Iron (Fe)

• Plant available form Fe2, Fe3
• Plant immobile, limited soil mobility
• Functions
• chlorophyll catalyst, co-enzyme activity
• Excess
• rarely occurs except on flooded soils, confounded
  with acid soils
• Deficiency
• Growth Reduction, interveinal chlorosis on young
  tissue, often becoming white, evident on high pH
  (gt7.5) soils, High P soils, high Cu, Zn soils and
  nematode infestations
• Notes Deficiency corrected with foliar
  applications of chelated Fe.

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Boron (B)

• Plant available form BO3-
• Plant immobile, soil mobile
• Functions
• cell wall formation and membrane integrity,
  calcium uptake, TLC movemetn
• Excess
• intraveinal darkening and death
• Deficiency
• Seed Set failure, internal (stem) breakdown,
  apical bud death
• Notes
• Regulate with pH control, legumes highly
  responsive to low (lt2 lbs/ac) fertilization.

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Zinc (Zn)

• Plant available form Zn2
• Plant immobile, high soil mobility
• Functions
• co-enzyme, PGR co-factor, TLC metabolism, protein
  synthesis
• Excess
• Fe Mg uptake interference, seen in over manured
  soils
• Deficiency
• Small leaf size, leaf size reduction, rosetting
  (short internodes), distorted or puckered leaf
  margins, interveinal chlorosis
• Notes
• leaches with irrigation, usually corrected with
  balanced fertilizer, chelates and sulfates in pots

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Copper (Cu)

• Plant available form Cu, Cu2
• limited plant mobility, not soil mobility
• Functions
• nitrogen metabolism, co-enzyme, TLC utilization
• Excess
• Fe Mg uptake interference, seen in over manured
  soils
• Deficiency
• Small, misshaped, wilted plants. Most commonly
  found in peat and potting soils
• Notes
• usually corrected with balanced fertilizer
  chelates and sulfates in pots

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Manganese (Mn)

• Plant available form Mn2
• Plant immobile, soil mobile
• Functions
• Co-factor for Photosynthesis, respiration and
  nitrogen metabolism
• Excess
• Reduced plant growth, brown spotting on leaves,
  chlorosis similar to Fe deficiency, usually acid
  soils
• Deficiency
• interveinal chlorosis followed by browns spots,
  producing a checkered red effect.
• Notes
• Deficiencies usually corrected with balanced
  fertilizer

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Molybdenum (Mo)

• Plant available form MoO4-
• Plant immobile, soil immobile
• Functions
• nitrate redox, protein synthesis
• Excess
• not plant toxic, high mammalian toxicity, usually
  a pollution problem
• Deficiency
• Interveinal chlorosis on older and midstem
  leaves, whiptailed (twisted) leaves
• Notes
• Primarily regulated with pH control

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Chlorine (Cl)

• Plant available form Cl-
• Very Plant mobile, high soil mobility
• Functions
• water relations (stomate activity), cation
  movement
• Excess
• usually confounded with sodium (salt) toxicity,
  salt injury, leaf burn, increased succulence
• Deficiency
• Club roots, wilted bronzing leaves, chlorosis
  then death
• Notes
• leaches with irrigation, usually corrected with
  potassium fertilizer.

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Sodium (Na)

• Plant available form Na
• Plant mobile (phloem), soil mobile
• Functions
• Osmotic regulation and Ionic balance
• Excess
• very toxic element, salt burn, poor water uptake,
  soil structure collapse, cell wall degradation
• Deficiency unkwown
• Notes
• Beneficial, not required, usually fully available
  in the soil

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Nickel (Ni)

• Plant available form Ni2
• Plant mobile (phloem), very limited soil mobility
• Functions
• forms urease, enhances Fe uptake, concentrated in
  reproductive organs (seed germination)
• Excess
• chlorosis and leaf margin necrosis
• Deficiency unknown, iron chlorosis (?)
• Notes
• Beneficial, not required, often fully available
  in the soil

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Cobalt (Co)

• Plant available form Co2
• Plant mobility not well understood, limited soil
  mobility
• Functions
• Nitrogen fixation in root nodules of legumes and
  non-legumes, deficiency limits seedling
  development (?)
• Excess unknown
• Deficiency unknown
• Notes
• limited amount in the soil, very reactive with a
  number of anions. Essential for bacteria
  (Rhizobium, etc.) growth

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Silicon (Si)

• Plant available form SiO3-
• Plant immobile, soil mobile
• Functions
• Cell wall component, drought tolerance
• Excess unknown
• Deficiency unknown
• Notes
• Beneficial nutrient for some plants. Best
  application methods not understood.

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Nutrient Uptake Problems

• Root growth limited
• traffic pan
• soil chemistry
• surface root hair activity
• Acidity
• hostile pH (lt5.5)
• plant specific
• solution
• soluble Ca source
• Stratification
• subsoil mining
• limited nutrient movement
• solution
• banding
• soluble nutrients
• soil mixing

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Soil Testing

• Identify Fields
• Multiple samples
• Individual fields
• Stratification
• 0-2
• 2-6
• Composite and Mail
• Multiple Labs
• TAMU
• others

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Soil Fertility Management

• Soil Test
• Proactive Mentality
• Utilize available nutrients
• Controlled nutrient mining
• Nutrient Removal
• Renter Mentality
• Replacement of mined nutrients

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Nutrient removed (lbs/ac) by grazing and hay
production
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Fertilizer Selection

• Dont guess soil test
• Match needs with available fertilizer
• Fertilizer
• Form
• Inorganic
• Organic
• Type
• Complete
• Incomplete

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Fertilizer Form

• Organic
• slow release
• generally poorly balanced (3-2-2 for PL)
• Micronutrients included
• Improved soil
• Inorganic
• fast release
• tailor application to field
• Micronutrients have to be added
• limited, if any, soil improvement

Decision - science, economics - fertilizer
availability - personal preference - everyone
has an opinion
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Fertilizer Type

• Incomplete
• Unbalanced
• over/under fertilizer rate
• Economics (?)
• Complete
• balanced, tailored to specifications
• blend unbalanced fertilizers to create balanced
  fertilizer

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Fertilizer Sources
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Blending Fertilizer
Soil Test Results Ryegrass for Rabbits 60-60-60
N-P2O5- K2O per acre 1000 sq. ft of
ryegrass 43560 sq. ft/acre
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Other Fertilizers

• Slow release
• Advantages
• fewer applications
• Low burn potential
• Release rate varied to clients need
• comparatively slow release
• Disadvantages
• Cost
• Limited Availability
• Release rate not governed by plant

• Manures Sludges
• Advantages
• Low burn potential
• Relatively slow release
• Micronutrient content
• Condition soils
• Disadvantages
• Salting potential
• Bulky
• Odor
• Weed seed
• Heavy Metals
• Availability/Variable cost

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Summary

• Soils are dynamic
• Soil Properties
• Physical
• Biological
• Chemical
• Soil change can be modified
• OM content
• Structure (traffic pans)
• Fertilizer cost money, use appropriately
• Youll learn something new every day