Mungbean Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Mungbean nutrient deficiency is one of the first things to check when the leaves of your monggo (mungbean) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are nitrogen, phosphorus, potassium, sulfur, zinc, iron, boron and molybdenum. 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 molybdenum move inside the plant, so a shortage shows on the old, lower leaves first. But sulfur, zinc, iron and boron 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 mungbean nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Mungbean 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 | Pale, thin plants with few branches whose lower leaves yellow and drop. The roots often have few or dead nodules. | Rhizobium inoculant for mungbean, Complete 14 14 14 |
| Phosphorus | old, lower leaves, the roots | Plants stay small and dark green with few pods, often without clear leaf marks. | Complete 14 14 14, 16 20 0 |
| Potassium | old, lower leaves, leaf edges and tips | Yellow patches on the edges of the lower leaves join up, with dark spots and curled edges. | Muriate of potash 0 0 60, Complete 14 14 14 |
| Molybdenum | old, lower leaves, the whole plant | Pale, slow monggo on acid soil that looks short of nitrogen, with few nodules that are white inside. | Sodium molybdate, Agricultural lime |
Shows first on the young leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Sulfur | young leaves and the tip, the whole plant | The young leaves turn pale yellow first, then the whole plant is evenly pale. | Gypsum, Ammonium sulfate 21 0 0 |
| Zinc | young leaves and the tip, between the veins | About a month after sowing, leaves turn small and yellow between green veins and the plants stop growing. | Zinc sulfate |
| Iron | young leaves and the tip, between the veins | New leaves turn yellow green with green veins, then fully yellow, on limey or high pH soil. | Ferrous sulfate |
| Boron | young leaves and the tip | The top of the plant bunches into a rosette and the upper leaves turn yellow or reddish at the tips. | Borax |
Before you buy fertilizer for a mungbean nutrient deficiency
So use the table to pick the likeliest mungbean 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 mungbean
Older leaves turn pale and then yellow and fall early, while the rest of the plant stays pale green. Stems are thin and weak, with fewer leaves and branches. In mungbean this usually means the root nodules are not working, so the plant cannot make its own nitrogen. You see it most at this stage: two to five weeks after emergence, when nodules should be fixing nitrogen.
Why nitrogen deficiency happens in monggo
In a legume this usually means poor nodulation: no inoculant in a field new to the crop, inoculant killed by sun or heat, very acid soil, waterlogging, hot dry soil, or too much nitrogen fertilizer near the seed, which stops nodules from forming.
How to tell it apart
Sulfur deficiency also yellows the whole plant, but the young leaves first. Iron deficiency yellows the young leaves between green veins. To be sure, dig, do not pull, a few plants 3 to 6 weeks after planting, wash the roots and cut some nodules open. Pink to red inside means they are working, white means not active yet, and brown, grey or mushy means dead. Yellow plants with few or dead nodules point to a nodulation failure, not a lack of fertilizer.
What to apply for nitrogen deficiency
Nodules cannot be added to a standing crop, so feed it. Give 10 to 20 kg of nitrogen per hectare, or a 2 percent DAP 18 46 0 spray (20 g per liter, 320 g in a 16 liter sprayer) every week. Urea 46 0 0 beside the rows also works. Give it early, before flowering.
- Rhizobium inoculant for mungbean
- Complete 14 14 14
- Urea 46 0 0
- Diammonium phosphate 18 46 0
Sold here with nitrogen: Atlas Granular Urea (46 0 0) by Atlas Fertilizer, Crown Champion Ammonium Sulfate by Aqua Hydroponic Prime Ventures (21 0 0 with 24 percent sulfur), 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, coat the seed with a mungbean Rhizobium inoculant just before planting and keep it out of the sun. Give only a small starter, about 20 kg of nitrogen per hectare from 150 kg of 14 14 14, because more nitrogen holds back nodules. Let a soil test and the crop's color set the season's nitrogen.
Phosphorus deficiency in mungbean
Plants grow slowly and stay short with dark, sometimes bluish green leaves, but there are often no clear marks on the leaves. Roots and nodules are few, branching is poor, and pods are few and late. You see it most at this stage: seedling to flowering.
Why phosphorus deficiency happens in monggo
Acid upland soils and soils low in phosphorus. Each harvest takes phosphorus away, so fields cropped for years without fertilizer run low.
How to tell it apart
Nitrogen deficiency makes plants pale, not dark. Drought also stunts plants, but leaves wilt in the heat of the day. To be sure, soil test for phosphorus before planting, or compare with a strip given 14 14 14.
What to apply for phosphorus deficiency
Use 30 to 45 kg each of phosphorus and potassium per hectare before planting on poor soils, or, without a soil test, 3 bags of Complete 14 14 14 per hectare on heavy soils and 4 bags on light soils as a basal dose. For a standing crop, give a 2 percent DAP 18 46 0 spray (20 g per liter, 320 g in a 16 liter sprayer) every 15 days for pulses.
- Complete 14 14 14
- 16 20 0
- Diammonium phosphate 18 46 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, apply phosphorus at planting every season and add compost or manure.
Potassium deficiency in mungbean
Yellow patches form on the edges of the lower leaves and join, until the leaf turns yellow. Dark spots appear on the yellow parts, leaf tips go black to brown and the leaf curls. Upper leaves stay green for a while. You see it most at this stage: flowering and pod filling.
Why potassium deficiency happens in monggo
Sandy soils, soils cropped for years without potash, and fields where straw and crop residues are always removed.
How to tell it apart
Magnesium deficiency yellows between the veins, not from the edges. Leaf spot diseases give round spots with rings, scattered over the leaf. To be sure, soil test for potassium, and check that the yellow edges start on the lowest leaves.
What to apply for potassium deficiency
Apply Muriate of potash 0 0 60 to the soil following the soil test. Give 30 to 45 kg of potassium per hectare on potassium poor soils. You can also give a 1 percent potash spray (10 g Muriate of potash per liter) at flowering.
- 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, use Complete 14 14 14 at planting and return crop residues to the field. Split the potash on sandy soil.
Sulfur deficiency in mungbean
The newest leaves turn pale yellow first, and over time the whole plant becomes evenly pale yellow. Growth slows and nodules work less well. You see it most at this stage: early growth to flowering.
Why sulfur deficiency happens in monggo
Sandy soils low in organic matter and years of sulfur free fertilizer. Legumes need a lot of sulfur, so they show it before cereals do.
How to tell it apart
Nitrogen deficiency starts on the old leaves. Iron deficiency keeps the veins green on yellow young leaves. To be sure, note that the youngest leaves are the palest, 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
Add a sulfur source such as Gypsum, which suits a legume because it adds no nitrogen. On soil poor in sulfur, about 11 kg of sulfur per hectare is enough for a row crop. Give it at planting or with the first side dress.
- Gypsum
- Ammonium sulfate 21 0 0
Sold here with sulfur: Crown Champion Ammonium Sulfate by Aqua Hydroponic Prime Ventures (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, use a fertilizer with sulfur, or gypsum, every few seasons on sandy soils. Test the soil every two or three years. Keep organic matter up with compost, manure or crop residues.
Zinc deficiency in mungbean
About a month after germination the leaves turn yellow between the veins, which stay green, and the yellow parts die early. New leaves come out small and yellowish, and plants grow little. You see it most at this stage: about 30 days after sowing.
Why zinc deficiency happens in monggo
High pH and calcareous soils, sandy soils, and heavy phosphorus on soils low in zinc.
How to tell it apart
Iron deficiency also yellows young leaves between the veins but turns the whole leaf yellow to white. Manganese deficiency is hard to tell apart. To be sure, soil test for zinc and pH, or a leaf test. In a soil test, less than 0.8 ppm of zinc is low.
What to apply for zinc deficiency
Give 25 kg Zinc sulfate per hectare as a basal dose. A 0.5 percent zinc sulfate spray (5 g per liter, 80 g in a 16 liter sprayer) at 20, 30 and 40 days after sowing.
- 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 soils, mix zinc sulfate into the basal fertilizer. Test the soil every two or three years. Do not overdo phosphorus.
Iron deficiency in mungbean
Newly opened leaves turn yellowish green while the veins stay green. In time the whole leaf turns yellow to almost white and growth slows. You see it most at this stage: seedling and early growth.
Why iron deficiency happens in monggo
High pH soils with free lime, and wet, cold or poorly aerated soil.
How to tell it apart
Zinc deficiency also gives small leaves and dead spots. Nitrogen deficiency starts on the old leaves. To be sure, soil pH test and a leaf test. In a soil test, less than 4.5 ppm of iron is low.
What to apply for iron deficiency
Give a 1 percent ferrous sulfate spray (10 g per liter, 160 g in a 16 liter sprayer) three times, 10 days apart. 25 kg ferrous sulfate per hectare as a basal dose.
- Ferrous sulfate
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 compost and choose fields that are not limey for mungbean. Test the soil every two or three years.
Boron deficiency in mungbean
The upper internodes stay short, so the top of the plant bunches into a rosette. Leaves near the growing point turn yellow and sometimes red, worst at the tips while the leaf bases stay green. You see it most at this stage: flowering and pod setting.
Why boron deficiency happens in monggo
Sandy soils low in organic matter, high pH soils and dry spells.
How to tell it apart
Zinc deficiency also gives short internodes, but with yellow between the veins. To be sure, leaf or soil test for boron before treating. In a soil test, less than 0.5 ppm of boron is low.
What to apply for boron deficiency
Give a 0.2 percent borax spray (2 g per liter, 32 g in a 16 liter sprayer) every 15 days. Do not put boron fertilizer in the seed row. Boron placed in a band poisons bean seed. 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 water during flowering in dry spells. Test the soil every two or three years.
Molybdenum deficiency in mungbean
Plants stay pale green to yellow and grow slowly, like a nitrogen shortage, since the nodules need molybdenum to fix nitrogen. Old leaves may curl and brown at the edges. The few nodules are small and white or green inside, not pink. You see it most at this stage: two to five weeks after the plants come up.
Why molybdenum deficiency happens in monggo
Acid soil below pH 5.5, sandy and leached soil, and fields that were never limed.
How to tell it apart
It looks the same as nitrogen shortage from failed nodules. Cut a few nodules open: pink means they fix nitrogen. To be sure, A soil pH test (below 5.5 is the warning sign) and a test spray of sodium molybdate on a few rows: they green up within one or two weeks. A soil pH test confirms the risk. A test spray of sodium molybdate on a few plants confirms the cause when they green up.
What to apply for molybdenum deficiency
Spray Sodium molybdate at 0.05 to 0.1 percent (8 to 16 grams in a 16 liter sprayer) once, two to three weeks after the plants come up. For the next crop, coat the seed with 2 to 4 grams of sodium molybdate per kilo of seed just before planting, with the inoculant. On acid soil, lime to pH 6 to 6.5. For the next crop, coat the seed with 2 to 4 grams of Sodium molybdate per kilo of seed just before planting.
- Sodium molybdate
- Agricultural lime
- Dolomite
Sold here with molybdenum: Tierramino Molybdenum by Unilox Far East Resources (16 percent molybdenum) and YaraVita Teprosyn Mo (0 15 0 with 15.3 percent 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 molybdenum deficiency in every crop.
To keep it away, lime acid soil to pH 6 to 6.5. Treat the seed with molybdenum and a Rhizobium inoculant on fields that have shown it before. Test the soil every two or three years.
A soil test is the surest check for any mungbean 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 monggo needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick monggo, 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
Mungbean nutrient deficiency questions
Why are my monggo leaves turning yellow?
What fertilizer fixes nitrogen deficiency in mungbean?
What fertilizer fixes phosphorus deficiency in mungbean?
What fertilizer fixes potassium deficiency in mungbean?
How do I know which nutrient my monggo lacks?
Find the missing nutrient and fix it
With Libre + Anee, read the whole guide: how to tell the deficiency from look alikes, how to be sure, what to apply, and the fertilizers sold here that supply it.
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