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Competency Area 4: Nutrient Sources, Analyses, Application Methods


If the typical northeast dairy farm ships 1 lb of N and P in milk for every 3-4 lbs of N and P imported, why do we need to worry about adding fertilizer at all?  Doesn't the rest come out in manure?

Manure nutrients are not 100% available.  Many get lost to the environment, runoff, etc.  To maximize plant growth and yield, the correct amounts of nutrients must be supplied when the plant needs them.  Using manure is hard because there is too much volume being produced to be able to apply it to the plants at the "right" time.

Appropriate use of fertilizer allows achievement of optimum yields.  For example:

  • N banded on corn often results in a 1-2 ton corn silage response
  • N can be sidedressed on corn if needed, promoting efficient nutrient uptake
  • P can be banded on very low to medium soil test corn fields, promoting efficient nutrient uptake
  • P can be banded P on legume seedlings
  • N can be topdressed on grass at spring green-up to give a boost

There is no one "correct" balance – the "right" answer is based on a particular farm's resources and goals.