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