INSEY Equation for Spring Wheat (Ciudad Obregon)
Nitrogen Use Efficiency, Nitrogen Fertilizers,nitrogen algorithms, NUE, Nitrogen and the Environment
Relationship between spring wheat grain yield and INSEY (in-season-estimated-yield = NDVI, Feekes 6 divided by the number of days from planting to sensing) over 7 locations and 2 crop cycles, Ciudad Obregon, MX.
Relationship between spring wheat grain yield and INSEY (in-season-estimated-yield = NDVI, Feekes 6 divided by the number of days from planting to sensing) over 6 locations and 2 crop cycles, Ciudad Obregon, MX.
      INSEY = NDVI/DFP YP0 =  506.42*EXP(INSEY*175.91) YPN = YP0 in the N-Rich Strip YPMAX determined by agronomists, where YPN cannot exceed YPMAX GNUP_YP0 = YP0 in kg/ha * 0.021% GNUP_YPN, = YPN in kg/ha * 0.021 FNR=(GNUP_YPN-GNUP_YP0)/0.70
  Feekes 6, NDVI Days from planting to sensing INSEY Predicted yield with no added fertilizer Predicted yield based on YP0 and RI Predicted yield based on YP0 and RI, not to exceed YPMAX Predicted Percent N in the grain Predicted Grain N uptake Predicted Fertilizer Nitrogen Requirement
    days   Mg/ha Mg/ha Mg/ha % kg/ha kg/ha
  NDVI DFP INSEY YP0 YPN YPN(cap) GNUP_YP0 GNUP_YPN FNR
NRICH 0.65 45 0.014444 6427.163514 6427.16351 6427.163514 141.3975973 141.3975973 0
Farmer 0.43 42 0.010238 3066.676552 6427.16351 6427.163514 67.46688414 141.3975973 105.6153045
Farmer 0.35 42 0.008333 2193.564294 6427.16351 6427.163514 48.25841446 141.3975973 133.0559755
Procedure:
1. Farmer is asked to Establish the Maximum Yield Achievable, For that Year (YPMAX)
2. Sense the N Rich Strip (NRS)
3. Sense a strip parallel to the NRS (Farmer Practice or FP)
4. Determine how many days from planting to sensing
5. Compute INSEY (NDVI/days from planting to sensing)
6. Predict yield
7. Predict grain N uptake in N Rich Strip
8. Predict grain N uptake farmer check
8. N rate = (grain N uptake in N rich strip/grain N uptake farmer check)/0.7
RI is not used for Spring Wheat, Ciudad Obregon

 

 
PROCEDURE MODIFIED by IVAN          
      INSEY = NDVI/DFP YP0 =  506.42*EXP(INSEY*175.91) GNUP = 34.157e0.0002(YP0) YPN = YP0 in the N-Rich Strip YPMAX determined by agronomists, where YPN cannot exceed YPMAX FNR=(GNUP_NRICH-GNUP_Farmer)/0.70
  Feekes 6, NDVI Days from planting to sensing INSEY Predicted yield with no added fertilizer Predict kg N in grain Predicted yield based on YP0 and RI Predicted yield based on YP0 and RI, not to exceed YPMAX Predicted Fertilizer Nitrogen Requirement
    days   Mg/ha   Mg/ha Mg/ha kg/ha
  NDVI DFP INSEY YP0 GNUP YPN YPN(cap) FNR
NRICH 0.65 45 0.014444 6427.163514 123.519649 6427.163514 6427.163514 0
Farmer 0.43 42 0.010238 3066.676552 63.073635 6427.163514 6427.163514 86.35144877
Farmer 0.35 42 0.008333 2193.564294 52.9675998 6427.163514 6427.163514 100.7886419

Procedure:
1. Farmer is asked to Establish the Maximum Yield Achievable, For that Year (YPMAX)
2. Sense the N Rich Strip (NRS)
3. Sense a strip parallel to the NRS (Farmer Practice or FP)
4. Determine how many days from planting to sensing
5. Compute INSEY (NDVI/days from planting to sensing)
6. Predict yield
7. Predict grain N uptake in N Rich Strip
8. Predict grain N uptake farmer check
9. N rate = (grain N uptake in N rich strip/grain N uptake farmer check)/0.7
RI is not used for Spring Wheat, Ciudad Obregon
 
 

This is data from Ivan Ortiz-Monasterio (1989 to 2002, different sites on the X axis) which basically shows that no matter how much N stress was induced from planting to first node (Feekes 6), maximum grain yields can be produced if adequate N is applied at that time. As a result. we will have to re-think an N algorithm for spring wheat.  Basically what this says is we need to first predict yield potential, and then based on the response index, fertilizer up to that max yield potential for that year, regardless of how much N stress was present early.



Schematic NFOA for Spring Wheat, Ciudad Obregon




Early-season N stress in spring wheat, Ciudad Obregon, MX.  Although severe, maximum grain yields were achieved when N was delayed, and applied at this stage of growth.

 
 
   
     
     
     
     
     
     
   
 
Nitrogen Use Efficiency, Nitrogen Fertilizers,nitrogen algorithms, NUE, Nitrogen and the Environment
Trimble Pocket Sensor, Greenseeker, NDVI, nitrogen