| |
|
Table
1. Nitrogen effects on yield and process quality. |
 |
|
|
|
N Rate
|
Effect on US #1 Yield
|
Effect on % Dry Matter
|
Effect on Sugar Levels
|
|
0-150
|
Increase
|
No change
|
Decrease
|
|
150-400
|
No change
|
Slight decrease
|
No change
|
|
>400
|
Decrease
|
Decrease
|
Increase
|
|
|
|
|
Table 2. Nitrogen fertilizer suggestions for potatoes.
|
|
|
|
|
N Soil Test Level
|
Soil Test Value
lb/a
|
N to Apply
lbs/acre
|
|
|
0-25
|
175
|
|
very low
|
26-50
|
150
|
|
|
51-75
|
125
|
|
medium
|
76-100
|
100
|
|
|
101-125
|
75
|
|
high
|
126-150
|
50
|
|
|
151-175
|
25
|
|
very high
|
176-200
|
0
|
|
excessive
|
>200
|
0
|
|
|
|
|
Table 3. Influence of nitrogen status on potato plant characteristics.
|
|
|
|
|
Organ
|
Deficiency
|
Excess
|
|
Leaves
|
interveinal yellowing
|
“nutrient leafroll”
|
|
Younger
|
green to yellow with age
|
deforming (severe excess)
|
|
Older
|
yellow to brown
|
|
|
Stems
|
slow growth, stunted erect stature
|
none
|
|
Roots
|
none
|
poor development
|
|
|
|
|
|
Plant or Soil Fertility Level
|
|
Deficient
|
Adequate
|
Slightly Small Tubers
|
|
Very small tubers
|
Optimal-sized tubers
|
High sugar levels
|
|
Low dry matter
|
High dry matter
|
Medium dry matter
|
|
Few usable
|
Most usable
|
Many usable
|
|
Over-mature tubers
|
Mature tubers
|
Immature tubers
|
|
Disease susceptible
|
Disease resistant
|
Disease and bruise susceptible
|
|
|
