Corn & Small Grain Management

Corn Nitrogen Algorithm Development

Components of the algorithm

Equations for Virginia Tech Corn Algorithm

Virginia Tech uses an exponential equation to predict Yield Potential, but uses a minimum value from the field (NDVI_Lo), and adds a term to subtract the nitrogen supplied at planting N preplant .

www.grains.cses.vt.edu/corn_algorithm.htm

Corn Coastal Plain

 

or a user-supplied value

(1) Maximum Yield Potential. Not environmental potential, but realistic for a whole-field yield

(2) Response Index
NDVI_Hi = Peak of Reference Strip (Best Spot)
NDVI_Lo = Low point of field (Poor Spot)

(3) Yield potential without additional N

(4) Conditional: computed value up to the MaxYield value.

Apply constraints:

(5) Qty of Nitrogen to apply [kg].

Nmin is user specified, N max is calculated

 

k a

function multiplier

YP0 eq: Crop Algorithm specific

k b

Exponent multiplier

YP0 eq: Crop Algorithm specific

k c

Constant

112 kg ha ­-1

YP0

 

Yield potential with no added nitrogen

YPN

 

Yield Potential, with added Nitrogen (uses Response Index)

Nmax

 

168 kg N ha-1 - preplant N