Nitrogen Information

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Nitrogen Information
N
By Becky McGuire
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Key Facts

• a.       N is in every plant cell
• b.      N is 78 of atmosphere
• c.       Production of N comes from ammonia (NH3)
  
• NH3 atmospheric N H
• d.      N fertilizer forms urea, ammonium
  nitrate, anhydrous ammonia, N solution (28)

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N Soil

• a.       N is very mobile in soil (it can leach
  from soil easily)
• b.      N losses
• 1.       used by plant
• 2.       leaching (draining from soil)
• 3.       erosion
• 4.       denitrification
• 5.       volatilization

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Nitrification

• a.       N must be in a from usable by plants
• b.      Ammonium (NH4), from OM or fertilizers
  is converted to NO3- (nitrate)
• c.       Carried out by bacteria in soil
• N must be in nitrate form to be absorbed by
  plants

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   Leaching

• a.       nitrates are not tightly held by clay
  and humus (OM)
• b.      can move with soil water
• c. losses great in sandy, coarse texture soil

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   Denitrification

• bacteria converting nitrate to elemental (N2)
  nitrogen which is then lost to the atmosphere
• a.       occurs under anaerobic conditions
• b.      anaerobic conditions occur when soil
  pores are filled with water and not air (heavy
  rain)
• c.       Nitrate losses are 15-30 of total
  applied N when area is flooded for 3-5 days

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Volatilization

• urea is converted to unusable form when
  applied on warm, moist soils. N lost to
  atomosphere.
• inject N to eliminate problem

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Nitrogen fixation

• N must be removed from atmosphere to be used by
  plants
• a.       N fixation legumes (beans, alfalfa)
  are able to fix N.
• b.      legumes have bacteria (rhizobia) on roots
  (in nodules) which remove N from the atomosphere.
• c.       Legumes are able to provide own N and
  dont need N fertilizer

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Nitrogen cycle

• a.       atmospheric N converted to usable N
  (nitrates) then converted back to atmospheric N
  (N2)

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sources of usable N

• --N fertilizers
• --animal waste
• --legumes
• --lightening, precipitation
• --crop residue

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Ways nitrates are lost

• --leaching, erosion, gas, plant use