Major Nutrients

NITROGEN

SYMPTOMS: Yellow coloration in a 'V' shaped pattern  

1. progresses from leaf end to leaf collar
2. progresses from lower to upper leaves

Causes: 

1. under-application of N fertilizer needs
2. underestimation of N release in manure
3. leaching of nitrate (rainfall/irrigation)
4. loss of N as a gas in soils  with history of standing water or in compacted sites
   

Remedies :  

1. appropriate fertilizer N application according to soil test recommendations.
2. analyze applied manure for N content, and provide proper N credit from the manure.
3. apply irrigation level appropriate for soil, avoid long-term ponding or standing water (> 12 hours)
4. install drainage tiles in heavier textured soils and /or minimize field compaction by reducing field trips in spring and fall, and drive in same wheel tracks.

PHOSPHOROUS

symptom:  Purple coloration of lower leaves

Causes:

1. under-application of P fertilizer needs
2. cooler/wetter weather which influence the soil temperature (environmentally induced) and reduces movement of P from soil to plant root.
3. inherited tendency of some hybrids

Remedies:

1. apply fertilizer P as a 'starter' application at the 20-30 lbs.P2O5 /a rate and according to soil test recommendations.
2. if the soil is a heavier texture, avoid planting at  the earlier part of the appropriate range of  planting dates (warmer weather can correct   symptoms).

SULPHUR

SYMPTOMS:pattern generally found in younger leaves

Causes:   

1. under-application of S fertilizer needs
2. reduced mineralization of organic -S to sulfate-S because of reduced soil temperatures or lower soil organic matter levels :
3. fields with eroded knolls and hillsides have lower organic matter than rest of the field
4. mineralization of organic-S to sulfate-S in fields under no-till cultivation is reduced compared to cultivated fields

Remedies:

1. apply appropriate fertilizer S levels after soil testing
2. analyze soil organic matter content (deficiencies are generally found in no-till soils with organic matter content of <2.5%)
3. Apply fertilizer in sulfate form as ammonium sulfate or ammonium thiosulfate . Elemental S may take several years to increase sulfate-S levels.

POTASSIUM

SYMPTOMS:  yellow and brown colouration of leaf

• occurs first on lower leaves
• may progress to upper leaves

Causes: 

1. under-application of K fertilizer needs
2. cooler/wetter weather (environmentally induced)
3. planted K inefficient hybrids

 Remedies:

1. apply an appropriate fertilizer K rate according to the soil test recommendation.
2. If the soil is a heavier texture, wait to plant at the latter part of the appropriate range of planting dates. (warmer weather can correct symptoms).
3. identify and plant K efficient hybrids

ZINC DEFICIENCY

SYMPTOMS

• occurs in upper leaves
• occurs in leaf middle, may progressing outward

Causes: 

1. under-application of Zn fertilizer needs
2. soil has high pH (>7.5)

Remedies:

apply appropriate Zn fertilizer as Zn-sulfate needs as starter fertilizer according to soil test recommendations. Applications of Zn-Chelates are not recommended due to high cost. Also avoid purchasing Zn-frits since this material if not very soluble.