Tillage

1
Tillage

• Chapter 10

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What is Tillage?

• the practice of keeping the soil mellow (soft)
  and free from weeds mechanically (physically)
• can be seedbed preparation or postemergence
  cultivation

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What are the purposes of tillage?

• 1) develop soil tilth (physical condition of the
  soil)
• 2) kill weeds
• 3) manage crop residue

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What is a seedbed?

• place where seeds germinate nourish young
  plants
• must be firm to allow seed to come in contact
  with soil particles to absorb moisture
• must be pourous to allow air to move, root
  development, water movement
• water will not easily penetrate hard soil to get
  to roots

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Seedbed Characteristics

• if soil is too loose, rain will wash away young
  plants
• some soils have excess water
• oxygen is needed by roots
• air and water conduct heat more rapidly than
  soil, looser soils warm up sooner
• plant residue on surface insulates, warms up
  slower, also provides buffer against wind

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What is Soil Tilth?

• The physical condition of the soil
• fitness for cultivation

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How is good soil tilth developed?

• till at proper time to maintain proper
  aggregation
• too wet during tillage makes soil lumpy, too dry
  during tillage makes soil too fine and likely to
  blow
• over tillage will destroy soil structure and lead
  to soil compaction

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What is the definition of a weed?

• a plant that grows out of place
• -tillage can cut roots or bury weeds

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Is crop residue a benefit or detriment?

• definitely a benefit
• helps control erosion, retain water, improve tilth

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What is primary tillage?

• the first tillage operation of a season
• loosen soil to permit air and water to penetrate
• dark soils absorb light, warm up quicker
• residue insulates, warms slower
• in wet areas soil is plowed
• in dry areas leave residue

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What are the types of tillage equipment?

• Moldboard Plow inverts soil, turns residue under
  soil surface

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Disk Plow

• rolling disks, similar to moldboard plow, better
  in sticky soils

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One-Way Disk Plow

• for dry soils, leaves more residue on soil
  surface than moldboard and disk plow

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What is summerfallow?

• tilling uncropped land in summer
• primary tillage is deepest, rest shallower
• leave residue

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Chisel Plow

• does not invert soil, uses chisels or sweeps that
  shatter the soil
• leaves residue on surface

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What is Hardpan?

• compacted soil layer below the soil surface
• created by continuous tillage at the same depth

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How can hardpan be corrected?

• use a subsoiler

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Disk Harrow

• similar to disk plow except smaller discs,
  tandem. cuts residue, but leaves on surface

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What is secondary tillage?

• all tillage operations after primary
• till at shallower depth

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Spike-Tooth Harrow

• steel spikes that break soil crust, uproot small
  weeds

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Rod Weeder

• rod turns as it is pulled beneath the soil
• rod turns opposite direction as wheels, lifts
  weeds and coarse material to surface
• packs seedbed

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Rotary Hoe

• hoe wheels on long shaft dig into soil (shallow)
• usually mounted on tractor for row crops

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What is minimum tillage?

• delay primary tillage until seeding

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What are the benefits of minimum tillage?

• 1) soil surface is left covered residue (conserve
  moisture)
• 2) redidue protects soil from erosion
• 3) reduced costs (fewer operations)
• 4) soil tilth improved (less compaction)
• -Weeds are controlled with chemicals

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What is stripcropping?

• alternating summerfallow and cropped fields

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What is contour tillage?

• strip cropping so that fields are all at the same
  elevation (along hills)
• slows water runoff

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What is Terracing?

• earth structure built across the slope to hold
  water

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