Silage and the Environment

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Silage and the Environment

• Fred Springborn
• Agriculture Agent
• Michigan State University Extension
• Montcalm County

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What is the environmental concern with silage?

• When improperly harvested, stored and/or handled,
  silage can produce a significant flow of leachate
  and other waste products

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Why the concern?

• Silage leachate in surface water
• has a fish kill potential because of high organic
  content
• has the same pollution potential from 300 tons as
  would the sewage generated by a city of 80,000
  people

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Why the concern?

• Silage leachate in groundwater
• contaminates through odor, increased acidity,
  ammonia, nitrate, bacteria and iron
• can release naturally occurring metals in aquifer
  and in soil because of low pH, which can increase
  concentration in groundwater

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Why the concern?

• Nitrate is the concern
• infants less than 6 months old should not consume
  water with 10 mg/L nitrate concentration
• livestock should not consume water with levels
  over 100 mg/L

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What to do

• First lets understand what silage is

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What is silage?

• Livestock feed

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What is silage?

• Livestock feed
• High Moisture Livestock Feed

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What is silage?

• Livestock feed
• High Moisture Livestock Feed
• Pickled Forage

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How silage is made

• Forage is piled or put into a container
• Microbes go to work

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How silage is made

• Microbial life begins the process of
  decomposition (rot)
• Silage is made when environmental conditions are
  just right for just the right amount of rot

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How silage is made

• The right amount of rot is when microbes have
  used up available oxygen and have produced enough
  by-product acid to prevent other microbes from
  producing more rotting

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Silage moisture content

• Silage can be made from all types of roughages as
  well as grain crops
• The amount of leachate produced depends on
• Type of forage
• Moisture content
• Nitrogen content
• Handling and storage conditions
• Moisture is the most crucial!

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Silage moisture content

• Managing the input moisture content for the
  method of silage storage used will help farmers
  produce quality feed while minimizing leachate
• Example
• Forages stored at 65 percent moisture content or
  higher can produce leachate
• For grass silage, a trickle of leachate is
  produced at 75 percent moisture to 79 gallons per
  ton at 85 percent moisture

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Silage moisture content

• About 75 percent of the leachate is produced in
  the first three weeks of storage, although it can
  continue to flow for up to three months
• Ensiling forages with moisture content above 70
  percent is not recommended
• Adding dry material as an absorbent reduces
  leachate and improves feed quality

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Silage moisture content

• Dropping moisture content 10 percent can change
  leachate production by 100 percent
• Most Michigan silage is of low moisture content
  (grasses and alfalfas are allowed to wilt prior
  to ensiling)

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Silo design and construction

• Upright silos can be classified as
• Oxygen limiting glass lined
• Oxygen limiting concrete

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Silo design and construction

• Upright silos can be classified as
• Poured concrete
• Stave non-airtight silo

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Silo design and construction

• Horizontal trench silos
• Above ground
• Earthen excavated
• Earthen excavated with concrete floor with clay
  sidewalls
• Above ground with concrete floor and sidewalls
  (bermed, concrete, or wooden)

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Silo design and construction

• Horizontal trench silos
• Above ground with concrete floor, no sidewalls

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Silo design and construction

• To minimize risk of groundwater contamination
  from horizontal and vertical silos
• All silos should have sloped concrete floors so
  that leachate can be diverted to a storage pit or
  a grass filter strip
• Leachate should not be allowed to enter surface
  water because of its high oxygen demand

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Silo design and construction

• To minimize risk of groundwater contamination
  from horizontal and vertical silos
• Silo caps or covers keep out rain, help maintain
  silage quality and reduce leachate

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Silo design and construction

• To minimize risk of groundwater contamination
  from horizontal and vertical silos
• Divert rain water away from silos

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Silo design and construction

• Silo bags
• Used with both high and low moisture silage
• Leachate can pool in bags and leak out when
  opened
• Use same options for managing leachate as in
  horizontal silos

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Silo design and construction

• Silo bags
• Repair holes in bags quickly to keep spoilage to
  a minimum
• Dispose of used plastic bags properly

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Silo location from well

• With concrete floors and drain control -- gt 50
  feet
• Without concrete floors -- gt 300 feet
• Silo --gt 50 feet from surface water

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Thank You ! Any Questions ?
Fred Springborn Agriculture Agent Michigan State
University Extension Montcalm County