Growing  Corn Crop Nutrition Advice

Everything you need to know about corn fertilization, best practices, suitable products, field trials, and more

Crop nutrition advice for growing corn (Zea mays)

  • Corn prefers a soil pH between 6.0 and 7.2, but it also performs well in higher pH calcareous soils.

  • Nitrogen and potassium are the nutrients absorbed by corn in the largest amount. The period of intensive uptake of these nutrient begins from the moment of appearance of the 6th leaf (V6) and continues through early reproductive stages (VT-R1).

  • On sandy soils, there is greater risk of nutrient leaching for anions like nitrate and sulfate as well as some cations like potassium and magnesium.

  • Ensuring adequate potassium nutrition can be one strategy to help a corn crop cope with water stress.

  • Corn is a warm weather crop and therefore performs best when temperatures during the growing season range between 77 and 86 oF.

Nutrient requirements

Average unit intake in kg t -1 dry grain + straw 20-3311-1428-37547

 Table 1. Nutrient uptake by maize grown for grain [Grzebisz, 2007] 

Dynamic of nutrient uptake over a crop season in corn

Source: modified from Buchner and Sturm 1985 and UNIFA 2015; BBCH scale according to Hack 1993.

Role of nutrients

Key parameterNP2O5K2OMgCaS
Number of grain in cob+++++++
Protein content +++++++++
Vegetative growth +++++++++

Nutrient deficiencies

NitrogenLeaf symptoms: younger leaves turn pale-yellow or light green, uniformly throughout the leaves. Early senescence of tips and mid-ribs. Later, V-shaped yellowing may appear on the leaves’ tips. Yellowing begins on the older lower leaves and progresses up the plant. Stalks are thin and spindly. Flowering- delayed. 
Low vegetative vigor. Root system becomes less prolific, slowing uptake of other nutrients. Reduced yield due to incomplete cob-tip kernel development.
PhosphorousIncidence: Insufficient P availability, and reduced uptake by roots due to cold, wet, or compacted soil.
Leaf symptoms: Dark green leaves; dark purple/yellow chlorosis, advancing along purple color. Reduced yields, delayed maturity. Slow growth rate, severe dieback. 
PotassiumIncidence: Insufficient potassium availability. Generally caused by a soil imbalance between K+, Ca2+ , Mg2+ and NH4+  Leaf symptoms: Dark green plants, show, mainly on their lower leaves, chlorosis along the leaf margins, developing to brown striping and necrosis. In older plants-browning of leaf tips and margins. Yield: Reduced, due to smaller and cob-tip defective kernels. 
CalciumLeaf symptoms: symptoms start on young leaves, which exhibit a light green colour or whitish spots or streaky lesions and are often hooked back. 
MagnesiumLeaf symptoms: Always appear on older leaves. Green-yellow plants with dark yellow interveinal. Chlorosis, advancing to rust-brown or purple necrosis. 
SulfurLeaf symptoms: Yellow striping pattern on the leaves. Firstly, on the newest leaves, without necrosis. Prominent interveinal chlorosis; veins are prominent over the leaves’ length. Low vegetative vigor.
At advanced stages: plant stunting.  
BoronLeaf symptoms: Yellow, white or transparent necrotic spots. Stalks stunted, due to shortened internodes. Yield: much reduced due to smaller and defective cobs. 
CopperLeaf symptoms: young leaves develop a bluish green tint and come out spiraled of the whorl. Old leaves’ tips  and edges wilt, turn white-grey and may die. 
Some necrosis of older leaf edges, like in K deficiency. Growing points: Dieback, often preceded by shortened internodes. Stalk: soft and limp.
IronLeaf symptoms: Chlorosis of interveinal areas, of young leaves of the summer flush, while veins and midrib remain green. At severe cases, the leaves may become almost white. Reduction in size. 
ManganeseLeaf symptoms: Young and medium formed leaves become olive-green, and develop uniform, white-yellow stripes in the midsection of the leaf. The stripes become necrotic with the dead tissue falling out of the leaf. Symptoms are like those for iron, and leaf tissue analysis is needed to confirm Mn deficiency. 
ZincLeaf symptoms: Pale yellowish green chlorotic stripe near the lower half of the leaf, or on each side of the midrib, advancing to pale brown or gray necrosis. Most prevalent at growth stages V2–V8. 


Nitrogen  deficiency                        Phosphorus deficiency


Potassium deficiencies


Magnesium deficiency                   Zinc deficiency


Sulfur  deficiencies                                  

Nitrogen deficiency in corn
Yellowing of the leaves showing sulphur deficiency in corn


Here are some frequently asked questions we received from corn growers

  • Potassium is the main nutrient for the crop to cope with water stress periods because it is involved in regulating stomatal activity and the water balance of plants. 

    Adequate magnesium nutrition in leaves may also play a role in plant stress response to high temperature, which can often accompany drought. 

  • We need to keep in mind that the export of nutrients at harvest is much higher for silage than in grain corn, especially potassium. As a result, fertilizer applications should match expected crop nutrient removal of both grain and vegetative parts of the plant.  

  • 616 bushels per acre! In 2019, David Hula achieved this world record in his own farm in Virginia, for which it was awarded the National Corn Growers Association top spot. 

  • Trick question! The purple color on  these young corn plants, seems to be P deficiency, but is often a hybrid characteristic. The coloring of the young plants in certain hybrids, takes place in response to low temperatures during plant emergence and establishment that cause an accumulation of sugars and anthocyanin.  

  • In environments were we are producing corn under irrigation, the amount of water is directly connected to the evaporative demand in the atmosphere as well as transpiration associated with crop growth stage. The evaporative demand is strongly connected to relative humidity, temperature, and wind. 

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