Corn Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Corn nutrient deficiency is one of the first things to check when the leaves of your mais (corn) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are nitrogen, phosphorus, potassium, zinc, sulfur, boron, magnesium, calcium, copper and iron. This guide shows where each one starts, how to be sure, and the fertilizer that fixes it.
Start with one question: did the change begin on the old leaves or on the young ones? Nitrogen, phosphorus, potassium and magnesium move inside the plant, so a shortage shows on the old, lower leaves first. But zinc, sulfur, boron, calcium, copper and iron stay where the plant first put them, so the young leaves and the growing tip show it first. After that, the color and the pattern narrow down which corn nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Corn nutrient deficiency signs, old leaves and young leaves
Shows first on the old leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Nitrogen | old, lower leaves, the whole plant | Lower leaves turn yellow in a V from the tip down the midrib, and plants are pale and thin. | Urea 46 0 0, Ammonium sulfate 21 0 0 |
| Phosphorus | old, lower leaves, the whole plant | Young plants are short and dark green, with purple red edges on the lower leaves. | 16 20 0, Complete 14 14 14 |
| Potassium | old, lower leaves, leaf edges and tips | Lower leaves dry brown along the edges while the middle stays green, and stalks break and fall. | Muriate of potash 0 0 60, Complete 14 14 14 |
| Magnesium | old, lower leaves, between the veins | Lower leaves get yellow to white stripes between the veins, later turning reddish purple. | Epsom salt / magnesium sulfate, Dolomite |
Shows first on the young leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Zinc | young leaves and the tip, between the veins | Wide white or pale yellow bands on both sides of the midrib from the leaf base, on short plants with bunched leaves. | Zinc sulfate |
| Sulfur | young leaves and the tip, the whole plant | The young upper leaves are the palest, while the lower leaves stay greener. | Ammonium sulfate 21 0 0, Gypsum |
| Boron | young leaves and the tip | Upper leaves have white spots and waxy brown streaks, and tassels and ears fail to come out. | Borax |
| Calcium | young leaves and the tip, leaf edges and tips | Tips of the young leaves stick together like a ladder, on very acid soil. | Agricultural lime, Dolomite |
| Copper | young leaves and the tip | The youngest leaves come out yellow, and their tips brown, roll and break. | Copper sulfate |
| Iron | young leaves and the tip, between the veins | Upper leaves turn pale yellow to white between the veins along their whole length. | Ferrous sulfate, Ammonium sulfate 21 0 0 |
Before you buy fertilizer for a corn nutrient deficiency
So use the table to pick the likeliest corn nutrient deficiency, then read its section below. Also keep in mind that dry soil, standing water, cold nights, a pest or a disease can look the same. That is why it pays to check the roots and the whole field first.
Nitrogen deficiency in corn
The lowest leaves turn pale, then yellow in a V shape that starts at the leaf tip and runs down the midrib. The yellowing climbs the plant if nothing is done, and the old leaves dry from the tip. Stalks stay thin and plants short, and ears come out small with poorly filled tips. You see it most at this stage: knee high to silking. The crop takes up the most nitrogen in the month before tasseling.
In sweet corn, it looks much the same. Lower leaves turn yellow in a V from the tip, and ears come out small with bare tips.
In white or glutinous corn, it looks much the same. Lower leaves turn yellow in a V from the tip down the midrib, and plants are pale and thin.
Why nitrogen deficiency happens in mais
Too little fertilizer, nitrogen washed out by heavy rain or irrigation, nitrogen lost from dry or hard soil, sandy soil. Fields flooded in hot weather. Plowing in a lot of dry crop residue also ties up nitrogen.
How to tell it apart
Sulfur deficiency also yellows the plant but starts on the young upper leaves. Potassium deficiency browns the leaf edges, not the midrib. To be sure, check that the yellowing started on the bottom leaves, in a V along the midrib. Compare with a few rows given extra urea, and have the soil tested before the next planting.
What to apply for nitrogen deficiency
Sidedress Urea 46 0 0 or Ammonium sulfate 21 0 0 beside the row and cover it with soil, then irrigate or wait for rain. Follow the soil test for the rate. For quick help, give a 1 percent urea spray (10 g per liter, 160 g in a 16 liter sprayer) twice, 15 days apart. Nitrogen given after the ears start filling helps much less. A usual side dress is 2 to 3 bags of Urea 46 0 0 per hectare at 25 to 30 days after planting, hilled in, and the rest before tasseling.
- Urea 46 0 0
- Ammonium sulfate 21 0 0
- Complete 14 14 14
Sold here with nitrogen: Atlas Granular Urea (46 0 0) by Atlas Fertilizer, Amigo Planters Ammonium Chloride by La Filipina (25 0 0), Agripower 46 0 0 (Locally Blended) Coated by Green Acres Agri Tech and Calcipro by Ramgo (15.5 0 0 with 18.8 percent calcium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to urea fertilizer, and the page on nitrogen deficiency in every crop. In anee.io, Anee, the smart farm technician, reads a photo of the leaf and tells you which nutrient is short.
To keep it away, test the soil before planting, split nitrogen between planting and knee high, and avoid packing the soil hard. Keep organic matter up with compost, manure or crop residues.
Phosphorus deficiency in corn
Young plants grow slowly and stay small and thin, with dark green leaves. The edges and tips of the older leaves turn reddish purple. The color can spread over the whole blade, while new leaves stay green. Later the crop matures late and ears are small, twisted or poorly formed. You see it most at this stage: seedling to knee high. The purple usually fades once plants pass about 1 meter, but the yield loss stays.
In sweet corn, it looks much the same. Young plants are short and dark green, with purple red edges on the lower leaves.
In white or glutinous corn, it looks much the same. Young plants are short and dark green, with purple red edges on the lower leaves.
Why phosphorus deficiency happens in mais
Acid soils and very alkaline soils that hold phosphorus tightly, cold wet soil, hard packed soil. Roots hurt by insects or fertilizer. Acid upland soils often run short of phosphorus, and very acid fields may need lime before it works.
How to tell it apart
Some hybrids show purple leaves when young even with enough phosphorus, so compare with other plants and the soil test. Magnesium deficiency also gives purple tints, but with yellow stripes between the veins. To be sure, soil test for available phosphorus before planting. A real shortage shows on many plants in the same soil patch, not on one hybrid only.
What to apply for phosphorus deficiency
Phosphorus works best at planting. For the standing crop, give a 2 percent DAP 18 46 0 spray (20 g per liter, 320 g in a 16 liter sprayer). For the next crop, put 16 20 0, Complete 14 14 14 or DAP in the furrow at planting, following the soil test. A usual basal dose is 2 to 4 bags of Complete 14 14 14 or Ammonium phosphate 16 20 0 per hectare, placed 5 cm beside and below the seed.
- 16 20 0
- Complete 14 14 14
- Diammonium phosphate 18 46 0
- Superphosphate 0 18 0
Sold here with phosphorus: Philphos 18 46 0 (Di Ammonium Phosphate), Atlas Super Gro (16 20 0) by Atlas Fertilizer, Amigo Planters Granular Single Super Phosphate by La Filipina (0 18 0 with 11 percent sulfur) and Triple Super Phosphate by Newman Chemicals (0 46 0). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to 16 20 0 fertilizer, and the page on phosphorus deficiency in every crop.
To keep it away, band phosphorus near the seed at planting, and lime very acid soils as the soil test advises.
Potassium deficiency in corn
The edges and tips of the lower leaves turn yellow, then brown and dry, while the middle of the leaf stays green. It moves up the plant if the shortage goes on. Stalks get weak and plants fall over late in the season, and ears are small and pointed with empty tips. You see it most at this stage: shows about 4 to 6 weeks after planting (around the 6 leaf stage) and again at grain filling.
In sweet corn, it looks much the same. Lower leaf edges dry brown, and ears are short and pointed with unfilled tips.
In white or glutinous corn, it looks much the same. Lower leaves dry brown along the edges while the middle stays green, and stalks break and fall.
Why potassium deficiency happens in mais
Sandy soils, highly weathered acid soils, hard, dry or waterlogged soils that limit roots. Fields where earlier crops took away a lot of potassium.
How to tell it apart
Nitrogen yellowing runs down the midrib in a V, while potassium burns the leaf edges. Drought scorch hits many leaves at once. To be sure, soil test for potassium, and look for brown edges starting on the bottom leaves. A leaf tissue test of the ear leaf confirms it.
What to apply for potassium deficiency
Sidedress Muriate of potash 0 0 60 beside the row early, following the soil test. Give a 1 percent potassium chloride or potassium sulfate spray (10 g per liter, 160 g in a 16 liter sprayer) twice, 15 days apart. A usual dose is 1 to 2 bags of Muriate of potash 0 0 60 per hectare at planting or with the first side dress.
- Muriate of potash 0 0 60
- Complete 14 14 14
Sold here with potassium: Atlas Muriate of Potash (MOP) by Atlas Fertilizer (0 0 60), Simplot Sulfate 0 0 50 by Nutranta, Potassium Nitrate by Parafield (13 0 46) and Qrop Mix Production 14 0 23 plus 13 Cao by Farmtech Agriland (14 0 23 with 9.3 percent calcium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to potash fertilizer, and the page on potassium deficiency in every crop.
To keep it away, return stalks and leaves to the field, and give potash at planting when the soil test is low. Keep organic matter up with compost, manure or crop residues. Split the potash on sandy soil.
Zinc deficiency in corn
Pale yellow to white bands appear between the veins, starting at the base of the leaf and running toward the tip. But the edges, tip and midrib stay green. Internodes stay short, so plants look stunted with bunched leaves. In severe cases the new leaves come out almost white (white bud), and leaf edges and stems turn reddish. You see it most at this stage: seedling to knee high. Plants often outgrow mild cases.
In sweet corn, it looks much the same. Wide white or pale yellow bands on both sides of the midrib from the leaf base, on short plants with bunched leaves.
In white or glutinous corn, it looks much the same. Wide white or pale yellow bands on both sides of the midrib from the leaf base, on short plants with bunched leaves.
Why zinc deficiency happens in mais
High pH soils (pH 7.5 and up), low organic matter, cool wet soil. Heavy phosphorus on soils already low in zinc. Zinc shortage is common on corn farms here.
How to tell it apart
Magnesium deficiency stripes the old leaves, not a band at the base of young leaves. Iron deficiency stripes the full length of the young leaf. To be sure, soil test for zinc and pH, and a leaf tissue test. In a soil test, less than 0.8 ppm of zinc is low.
What to apply for zinc deficiency
Spray 0.5 percent Zinc sulfate (5 g per liter, 80 g in a 16 liter sprayer) twice, 15 days apart. For the soil, give 20 to 25 kg zinc sulfate per hectare. Band about 19 kg of zinc sulfate per hectare near the row.
- Zinc sulfate
Sold here with zinc: Harvester Zinc Sulphate Heptahydrate by Universal Harvester (22 percent zinc), Petbowe Zinc Sulphate Monohydrate (33 percent zinc), Tierramino ZN by Unilox Far East Resources (7 0 0 with 10 percent zinc) and Liquid Chelate Zinc with Sulfur by Sagrex (10 percent zinc and 5 percent sulfur). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to fertilizer with zinc, and the page on zinc deficiency in every crop.
To keep it away, on high pH or zinc poor soils, add zinc sulfate to the basal fertilizer. A broadcast dose lasts several seasons. Test the soil every two or three years.
Sulfur deficiency in corn
The whole plant looks pale like nitrogen deficiency. But the young upper leaves are the palest, and up close they show faint yellow stripes between the veins. Plants stay short and upright, and maturity comes late. You see it most at this stage: early growth. It may fade as roots go deeper and the soil warms.
In sweet corn, it looks much the same. The young upper leaves are the palest, while the lower leaves stay greener.
In white or glutinous corn, it looks much the same. The young upper leaves are the palest, while the lower leaves stay greener.
Why sulfur deficiency happens in mais
Acid sandy soils, low organic matter, waterlogged soils, and heavy rain soon after planting. Years of urea and other sulfur free fertilizers make it more likely.
How to tell it apart
Nitrogen deficiency starts on the old lower leaves. Zinc deficiency gives a white band at the leaf base. To be sure, note which leaves yellowed first, then test soil and leaves for sulfur. A soil test for sulfur and a leaf test confirm it. In a soil test, less than 10 ppm of sulfate sulfur is low.
What to apply for sulfur deficiency
Use Ammonium sulfate 21 0 0 for the next nitrogen sidedress, and place a sulfur bearing fertilizer near the row. Follow the soil test for the rate. A usual dose is 50 to 100 kg of Ammonium sulfate 21 0 0 per hectare (12 to 24 kg of sulfur), or 100 to 200 kg of Gypsum, at planting.
- Ammonium sulfate 21 0 0
- Gypsum
Sold here with sulfur: Atlas Ammosul 21 0 0 by Atlas Fertilizer (21 0 0 with 24 percent sulfur), Philphos Gypsum (22.2 percent calcium and 17.4 percent sulfur), Harvester Sulphate of Potash by Universal Harvester (0 0 50 with 17.5 percent sulfur) and Agsmart Kieserite Granule (20 percent sulfur and 16.3 percent magnesium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to ammonium sulfate fertilizer, and the page on sulfur deficiency in every crop.
To keep it away, include ammonium sulfate or another sulfur source in the program on sandy or low organic matter soils.
Boron deficiency in corn
Young leaves get small white or yellow spots and raised, waxy brown streaks, and turn brittle. Upper internodes stay short. Tassels and ear shoots are small and may not come out, so few kernels set. You see it most at this stage: before tasseling up to silking.
In sweet corn, it looks much the same. Upper leaves have white spots and waxy brown streaks, and tassels and ears fail to come out.
In white or glutinous corn, it looks much the same. Upper leaves have white spots and waxy brown streaks, and tassels and ears fail to come out.
Why boron deficiency happens in mais
Rare. Sandy soils low in organic matter, high pH soils and drought.
How to tell it apart
Drought also delays ear shoots and spoils pollination, so both can happen together. Zinc gives bands, not spots. To be sure, test leaves and soil for boron before treating. A soil test for boron and a leaf test confirm it. In a soil test, less than 0.5 ppm of boron is low.
What to apply for boron deficiency
Give a 0.5 percent borax spray (5 g per liter, 80 g in a 16 liter sprayer) every 15 days. Corn is very sensitive to too much boron. So never go above the advised rate and do not put boron in the seed row. A usual soil dose is 5 to 10 kg of Borax per hectare (0.5 to 1 kg of boron), mixed evenly with the basal fertilizer.
- Borax
Sold here with boron: Etifert 11 (Borax Decahydrate) by Zetryl Chem (11 percent boron), Fertibagra 15G by Unilox Far East Resources (14.6 percent boron), B17 (Boric Acid) by Newman Chemicals (17 percent boron) and Better Yield by Bacphil Planters Fertilizer (0 0 0.9 with 10 percent boron). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to foliar fertilizer, and the page on boron deficiency in every crop.
To keep it away, keep organic matter up, and irrigate at tasseling during dry spells. Test the soil every two or three years.
Magnesium deficiency in corn
Yellow to white stripes appear between the veins of the lower leaves, sometimes with small dead spots that look like a string of beads. Later the old leaves take on a reddish purple color and can die back at the tips and margins. Growth stays normal unless it is severe. You see it most at this stage: early growth to the middle of the season.
In sweet corn, it looks much the same. Lower leaves get yellow to white stripes between the veins, later turning reddish purple.
In white or glutinous corn, it looks much the same. Lower leaves get yellow to white stripes between the veins, later turning reddish purple.
Why magnesium deficiency happens in mais
Very acid, sandy soils in rainy areas, fields that were never limed, and heavy potash on soils already low in magnesium.
How to tell it apart
Iron and manganese deficiency give similar stripes but on the young leaves. Zinc gives a band near the base of young leaves. To be sure, soil test for magnesium and pH, and a leaf test.
What to apply for magnesium deficiency
Apply magnesium sulfate (Epsom salt) to the soil or as a leaf spray. Give a 2 percent spray (20 g per liter, 320 g in a 16 liter sprayer). On acid soils use Dolomite following the soil test. A usual dose is 100 to 150 kg of Kieserite or 150 to 200 kg of Magnesium sulfate per hectare at planting. On acid soil, 1 to 2 tons of Dolomite mixed in before planting both limes and feeds.
- Epsom salt / magnesium sulfate
- Dolomite
Sold here with magnesium: Dolomite by A6 Agrisource (24 percent calcium and 11 percent magnesium), Agsmart Kieserite Granule (20 percent sulfur and 16.3 percent magnesium), DDDD Planter's Choice Magnesium Sulphate Monohydrate by Modern Time (15.1 percent magnesium) and Zetryl MAG 9 by Zetryl Chem (9 percent magnesium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to complete fertilizer, and the page on magnesium deficiency in every crop.
To keep it away, lime acid fields with dolomite, and do not overdo potash.
Calcium deficiency in corn
The tips of new leaves stick to the leaf below, so the whorl looks like a ladder or a row of hooks. Young leaves are light green with whitish streaks and brittle, brown, sticky edges. Plants can be badly stunted. You see it most at this stage: early growth.
In sweet corn, it looks much the same. Tips of the young leaves stick together like a ladder, on very acid soil.
Why calcium deficiency happens in mais
Rare. It needs very acid soils (below pH 5), unlimed weathered uplands, or soils where magnesium and potassium crowd out calcium. On such soils aluminum and manganese damage usually show first.
How to tell it apart
Boron deficiency also hurts the growing tip but gives white spots and short upper internodes. Acid soil damage from aluminum stunts the roots. To be sure, soil pH and calcium test. A soil test for calcium and pH, and a leaf test, confirm it.
What to apply for calcium deficiency
Apply Agricultural lime or Dolomite following the soil test. A very acid field may need 3 to 4 tons of lime per hectare. Gypsum adds calcium without raising the pH. Lime 2 to 4 weeks before planting. Calcium sprays go on young fruit from fruit set.
- Agricultural lime
- Dolomite
- Gypsum
Sold here with calcium: Planters Products Lifelime (36.2 percent calcium), Dolomite by A6 Agrisource (24 percent calcium and 11 percent magnesium), Calcipro by Ramgo (15.5 0 0 with 18.8 percent calcium) and Philphos Gypsum (22.2 percent calcium and 17.4 percent sulfur). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to fertilizer for tomatoes, and the page on calcium deficiency in every crop.
To keep it away, lime acid uplands before planting, ahead of the rains. Keep potash in balance with magnesium and calcium.
Copper deficiency in corn
New leaves already look yellow when they unroll from the whorl, then their tips brown, curl and snap off. Striping much like an iron shortage can show, the stalk goes soft and floppy, and older leaves may die along their margins. You see it most at this stage: early growth.
Why copper deficiency happens in mais
Rare. Seen on peat and other high organic matter soils and soils above pH 7.5. A few corn farms here do run short of copper.
How to tell it apart
Iron deficiency gives similar streaks. Nitrogen plus sulfur shortage in cool weather can look like mild copper deficiency. To be sure, soil and leaf test for copper. In a soil test, less than 0.2 ppm of copper is low.
What to apply for copper deficiency
Give a 0.2 percent copper sulfate spray (2 g per liter, 32 g in a 16 liter sprayer). A short soil may need about 1 kg of copper per hectare, so let the soil test set the rate. Spray the young leaves in the cool of the day, soon after sunrise or near sunset.
- Copper sulfate
Sold here with copper: Grower's Choice Copper Sulphate Pentahydrate by Zetryl Chem (25 percent copper and 12 percent sulfur), Liquid Chelate Copper with Sulfur by Sagrex (5 percent copper and 2 percent sulfur), Indra by Farmtech Agriland (2 percent zinc, 2 percent manganese and 2 percent copper) and Biozome by Manchem Industries (12 percent sulfur, 12 percent zinc, 3 percent manganese, 1 percent magnesium and traces of iron, copper, boron, molybdenum). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to foliar fertilizer, and the page on copper deficiency in every crop.
To keep it away, test for copper before planting on peat or alkaline soils. Never repeat copper without a test: it stays in the soil for years.
Iron deficiency in corn
Long pale green to nearly white stripes run between the veins of the upper leaves, while the veins stay green. As it worsens the veins pale too, the crop looks bleached, and plants are stunted. You see it most at this stage: seedling and early growth.
Why iron deficiency happens in mais
Rare in corn. Only on high pH, calcareous soils, worse when the soil is cold, wet and poorly aerated.
How to tell it apart
Magnesium also stripes leaves, but the old ones. Zinc gives a band at the base of the leaf, not stripes the full length. To be sure, soil pH test (calcareous soil is the warning sign) and a leaf test. In a soil test, less than 4.5 ppm of iron is low.
What to apply for iron deficiency
Give 20 to 25 kg ferrous sulfate per hectare to the soil, or a 1 percent ferrous sulfate spray (10 g per liter, 160 g in a 16 liter sprayer) every week until new leaves come out green. Spray the young leaves in the cool of the day, soon after sunrise or near sunset.
- Ferrous sulfate
- Ammonium sulfate 21 0 0
Sold here with iron: DDDD Planter's Choice Ferrous Sulphate Heptahydrate by Modern Time (19 percent iron), Ferrous Sulfate Monohydrate by Zetryl Chem (30 percent iron), Ferrous Sulphate Monohydrate by Newman Chemicals (30 percent iron) and Liquid Chelate Iron with Sulfur by Sagrex (5 percent iron and 3 percent sulfur). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to foliar fertilizer, and the page on iron deficiency in every crop.
To keep it away, add manure and use an acid forming fertilizer such as ammonium sulfate on calcareous soil. Test the soil every two or three years.
A soil test is the surest check for any corn nutrient deficiency. Before you buy, ask your Municipal Agriculture Office where to send a soil sample. The DA regional soil laboratories test soil, and the result says how much of each fertilizer your mais needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick mais, say where the leaves changed first and what you see, and get the fertilizers sold here that fix it.
- Anee, the smart farm technician, reads a photo of the leaf
- The cropping calendar dates every fertilizer application of your season
Corn nutrient deficiency questions
Why are my mais leaves turning yellow?
What fertilizer fixes nitrogen deficiency in corn?
What fertilizer fixes phosphorus deficiency in corn?
What fertilizer fixes potassium deficiency in corn?
How do I know which nutrient my mais lacks?
- Yara: Nitrogen deficiency in maize
- Yara: Phosphorus deficiency in maize
- Yara: Potassium deficiency in maize
- Yara: Zinc deficiency in maize
- Yara: Sulphur deficiency in maize
- Yara: Magnesium deficiency in maize
- Yara: Calcium deficiency in maize
- Yara: Boron deficiency in maize
- Yara: Copper deficiency in maize
- Yara: Iron deficiency in maize
Find the missing nutrient and fix it
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