Cropside: Staying on top of NPK

N CALCULATOR RECOMMENDATION for Corn

Factor	Input	N Rate (lb/acre)
Base N Requirement (select soil texture)	Loam	+ 28
Yield Adjustment (enter proven yield)	175	+ 135
Heat Unit Adjustment (enter CHU rating)	3000	+ 7
Previous Crop Adjustment (enter previous crop)	soybeans	– 27
Prices: Enter Expected Corn Price ($/bushel)	$4.85
Enter Fertilizer Price ($/lb of N)	$0.59
Price Ratio Adjustment		– 11
Total N Recommendation		132
Enter Starter N		12
Enter Manure N		0
Pre-plant Additional N Recommendation		120
Sidedress Additional N Recommendation		96

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TIP:
You can go to www.gocorn.net to change the information to match your 2011 corn cropping scenarios.

omafra p recommenation table for corn

Soil Test P	Phosphate (P2O5) Required
(ppm)	(kg/ha)	(lb/ac)
0 – 3	110	99
4 – 5	100	90
6 – 7	90	81
8 – 9	70	63
10 – 12	50	45
13 – 15	20	18
16 – 20	20	18
21 – 30	20	18
31 – 60	0	0
61 +	0	0

 

 

 

 

 

 

 

 

 

 

 

TIP:
P deficiency is generally associated with early stages of corn growth and it will grow out of the purpling once the root system develops. But, early deficiency may reduce yield and/or delay maturity. Be sure there is enough early season P?available.

omafra k recommendation table for corn

Soil Test K	Potash (K2O) Required
(ppm)	(kg/ha)	(lb/ac)
0 – 15	170	153
16 – 30	160	144
31 – 45	140	126
46 – 60	110	99
61 – 80	80	72
81 – 100	50	45
101 – 120	30	27
121 – 150	0	0
151 – 250	0	0
251 +	0	0

 

 

 

 

 

 

 

 

 

 

 

tip:
Be aware of K soil tests that have dropped over the last five years. Recent plot work has shown significant yield advantage to corn starter fertilizers that have some K in them, especially when soil tests are below 80 PPM. •