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Copy link 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)
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Corn, also known as maize, belongs to the Poaceae family
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Canada, cultivated across multiple provinces for grain, silage, and specialty markets. It plays a significant role in the country's livestock feed industry, food processing sector, and biofuel production.
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Corn thrives in warmer growing regions, and heat units (CHUs) play a crucial role in determining which hybrids can be grown in different parts of the country.
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Over 60% of Canadian corn is grown in Ontario
Nitrogen deficiency in corn
Yellowing of the leaves showing sulphur deficiency in corn
What soil type, pH and climate does corn prefer?
- Corn prefers a soil pH between 6.0 and 7.2, but it also performs well in higher pH calcareous soils.
- It thrives on well-drained soils with proper aeration, with loamy soil (loam – a mix of sand, silt and clay) often considered ideal as it provides good fertility, water retention and drainage.
- 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.
- Corn is a warm weather crop and therefore performs best when temperatures during the growing season range between 77 and 91 °F and is typically grown at lower elevations in Canada, where there is adequate heat accumulation.
- Shorter-season hybrids have been developed to expand corn production into Western Canada.
- While relatively drought-tolerant, corn requires adequate moisture during key growth stages such as flowering and grain filling with water stress during critical stages negatively impacting yields.
- Ensuring adequate potassium nutrition can be one strategy to help a corn crop cope with water stress.
What nutrients are most important for corn yield and quality?
While nitrogen is generally considered one of the most important nutrients for corn growth, adequate and balanced fertility (included all 16 essential plant nutrients) are essential for crop growth and ultimately yield. Recommendations typically include considerations for the three primary macronutrients—nitrogen (N), phosphorus (P), and potassium (K)—as well as secondary macronutrients and micronutrients.
- 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).
- For nitrogen, split applications may be recommended to ensure a steady supply throughout the growing season, supporting robust plant development and grain formation.
- In addition to nitrogen (N), phosphorus (P), and potassium (K), secondary macronutrients such as calcium, magnesium and sulfur are all essential for corn production. Secondary macronutrients play vital roles in various physiological processes, contributing to plant structure and overall health.
It’s crucial for corn growers to work closely with agronomists and utilize soil testing to tailor fertilizer applications to their specific field conditions. The goal is to achieve a balanced and targeted nutrient supply, promoting healthy crop development, maximizing yield, and ensuring long-term soil fertility. Additionally, sustainable practices such as precision agriculture and the use of environmentally friendly fertilizers may also be recommended to support both productivity and environmental stewardship.
Nutrient uptake
| N | P2O5 | K2O | Mg | SO3 | Ca | |
|---|---|---|---|---|---|---|
| Kg/ha | Kg/ha | Kg/ha | Kg/ha | Kg/ha | Kg/ha | |
| Average unit intake in kg t -1 dry grain + straw | 20-33 | 11-14 | 28-37 | 5 | 4 | 7 |
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 parameter | N | P2O5 | K2O | Mg | Ca | S |
|---|---|---|---|---|---|---|
| Yield | ++ | + | ++ | + | + | + |
| Number of grain in cob | + | + | ++ | + | + | + |
| Protein content | ++ | + | + | ++ | + | ++ |
| Vegetative growth | ++ | + | + | ++ | + | ++ |
Nutrient deficiencies
| Nutrient | Description | |
|---|---|---|
| Nitrogen | Leaf 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. |
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| Phosphorous | Incidence: 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. |
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| Potassium | Incidence: 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. | |
| Calcium | Leaf symptoms: symptoms start on young leaves, which exhibit a light green colour or whitish spots or streaky lesions and are often hooked back. | |
| Magnesium | Leaf symptoms: Always appear on older leaves. Green-yellow plants with dark yellow interveinal. Chlorosis, advancing to rust-brown or purple necrosis. | |
| Sulfur | Leaf 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. |
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| Boron | Leaf symptoms: Yellow, white or transparent necrotic spots. Stalks stunted, due to shortened internodes. Yield: much reduced due to smaller and defective cobs. | |
| Copper | Leaf 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. |
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| Iron | Leaf 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. | |
| Manganese | Leaf 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. | |
| Zinc | Leaf 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
How do nutrient management plans meet the needs of various varieties of corn?
Corn cultivation in Canada involves a diverse range of corn varieties (dent or field corn, waxy corn, popping corn, flour corn and high-oil corn) each tailored to specific purposes and growing conditions. For sweet corn, Sugar Enhanced (SE) and Supersweet (Sh2) types are common varieties, however, it’s important to note that farmers often select corn hybrids based on factors such as local climate, soil characteristics, disease resistance, and specific trait requirements.
Each variety can have varying agronomic needs based on factors such as genetics, traits, maturity, and intended use. It’s crucial for farmers to work closely with agronomists, seed advisors, and extension services to select the most suitable corn varieties for their specific conditions and management practices. Tailoring agronomic practices to the characteristics of chosen varieties can contribute to successful corn production and maximize yields. Additionally, ongoing research and advancements in breeding technologies continue to influence the agronomic landscape for corn production.
Additionally, new hybrids are continually being developed, and the popularity of hybrids can change based on evolving agricultural practices and technologies. For the most current information on popular dent corn hybrids in Canada, it is recommended to consult with local agricultural extension services, seed dealers, or seed companies.
Q&A
Here are some frequently asked questions we received from corn growers
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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.
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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.
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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.
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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.
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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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