Winged bean Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Winged bean nutrient deficiency is one of the first things to check when the leaves of your sigarilyas (winged bean) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are phosphorus, nitrogen, potassium, calcium 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? Phosphorus, nitrogen, potassium and molybdenum move inside the plant, so a shortage shows on the old, lower leaves first. But calcium 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 winged bean nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Winged bean nutrient deficiency signs, old leaves and young leaves
Shows first on the old leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Phosphorus | old, lower leaves, the roots | Vines stay short and weak on red, acid soil, with few pods and small roots. | 16 20 0, Complete 14 14 14 |
| Nitrogen | old, lower leaves, the whole plant | Pale, slow vines whose roots have few pink nodules. | Rhizobium inoculant (cowpea group), Complete 14 14 14 |
| Potassium | old, lower leaves, leaf edges and tips | Older leaves yellow and scorch at the edges, and the vines fix less nitrogen. | Muriate of potash 0 0 60, Complete 14 14 14 |
| Molybdenum | the whole plant | Pale, nitrogen starved vines on very acid soil even when nodules are present. | Sodium molybdate, Ammonium molybdate |
Shows first on the young leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Calcium | young leaves and the tip, the roots | Growing tips and roots fail to develop on very acid soil. | Agricultural lime, Dolomite |
Before you buy fertilizer for a winged bean nutrient deficiency
So use the table to pick the likeliest winged bean 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.
Phosphorus deficiency in winged bean
Vines grow slowly and stay short, leaves are dark green, and pods and tubers are few. Nodules form poorly and fix little nitrogen. You see it most at this stage: early growth to flowering.
Why phosphorus deficiency happens in sigarilyas
Red, acid, phosphorus poor soils. On such soils the vines grow poorly from lack of phosphorus, not from the acid, so lime alone does not help.
How to tell it apart
Nitrogen deficiency makes vines pale. Waterlogging also stunts plants, with yellow leaves. To be sure, soil test for available phosphorus before planting.
What to apply for phosphorus deficiency
Apply a phosphorus fertilizer such as 16 20 0, Complete 14 14 14 or Superphosphate 0 18 0 at planting, following the soil test. Vines given phosphorus grow far better than vines given only lime. A usual basal dose is 2 to 3 bags of Complete 14 14 14, or 1 to 2 bags of Diammonium phosphate 18 46 0, per hectare in the furrow at planting.
- 16 20 0
- Complete 14 14 14
- 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. 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, put phosphorus in the planting rows each season. Lime only if the soil test calls for it.
Nitrogen deficiency in winged bean
Lower leaves pale and yellow and the vine stays light green and slow. Winged bean gets its nitrogen from root nodules, so pale vines usually mean the nodules are few or not working. Low phosphorus and potassium also cut nodule activity. You see it most at this stage: three to six weeks after planting.
Why nitrogen deficiency happens in sigarilyas
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. In winged bean, low phosphorus and potassium also reduce nitrogen fixation.
How to tell it apart
Phosphorus shortage stunts the vine but keeps leaves dark. Sulfur deficiency yellows the young leaves first. 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
Feed the vines with a light sidedress of Urea 46 0 0 or Complete 14 14 14, following the soil test. Correct phosphorus and potassium so the nodules can work. If the nodules failed, 10 to 20 kg of nitrogen per hectare is enough: about half a bag of Urea 46 0 0 beside the rows, before flowering.
- Rhizobium inoculant (cowpea group)
- Complete 14 14 14
- Urea 46 0 0
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.
To keep it away, inoculate seed with a cowpea group Rhizobium inoculant, keep it shaded, and fertilize with phosphorus and potassium at planting. Keep organic matter up with compost, manure or crop residues.
Potassium deficiency in winged bean
Older leaves yellow or scorch at the margins, starting on the lower leaves. Winged bean fixes much less nitrogen when short of potassium, as with phosphorus, so the vines may stay short with pale leaves. You see it most at this stage: mid growth to pod filling.
Why potassium deficiency happens in sigarilyas
Sandy and highly weathered soils and fields cropped without potash.
How to tell it apart
Magnesium deficiency yellows between the veins. To be sure, soil test for potassium.
What to apply for potassium deficiency
Apply Muriate of potash 0 0 60 or Complete 14 14 14 following the soil test. A usual dose is 1 bag of Muriate of potash 0 0 60 per hectare at planting.
- 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, include potash at planting and return vines to the soil. Keep organic matter up with compost, manure or crop residues. Split the potash on sandy soil.
Calcium deficiency in winged bean
The buds at the vine ends and the root tips stop growing, so the vines stall and the roots stay short. Winged bean short of calcium also fixes less nitrogen in its root nodules. You see it most at this stage: early growth.
Why calcium deficiency happens in sigarilyas
Very acid soils, usually below pH 5, low in organic matter. Heavy potash or ammonium fertilizer, salty soil and dry spells keep calcium from reaching fruit and young leaves.
How to tell it apart
Boron deficiency also kills growing tips but crinkles young leaves. 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 on acid soils, or Gypsum where pH is fine, following the soil test. On acid soil, lime by the soil test: usually 1 to 3 tons of Agricultural lime or Dolomite per hectare, mixed in 2 to 4 weeks before planting. On soil that is not acid, use 200 to 500 kg of Gypsum per hectare.
- 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, test the soil and lime well ahead of planting if it is very acid. Keep potash in balance with magnesium and calcium.
Molybdenum deficiency in winged bean
Vines are pale and small, just like nitrogen deficiency, because nodules need molybdenum to fix nitrogen. In some vegetables the leaf edges brown and cup upward. You see it most at this stage: early growth.
Why molybdenum deficiency happens in sigarilyas
Acid, sandy and highly weathered soils, where molybdenum is held tightly.
How to tell it apart
Nitrogen deficiency from poor inoculation looks the same. Check the soil pH. To be sure, soil pH test and a look at the nodules. 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
Liming to pH 6.0 or above often fixes it. Otherwise treat seed with about 35 g of molybdenum per hectare, or spray about 140 to 210 g of sodium or ammonium molybdate per hectare. Spray Sodium molybdate at 0.05 to 0.1 percent (8 to 16 grams in a 16 liter sprayer) once or twice on young plants.
- Sodium molybdate
- Ammonium molybdate
- Agricultural lime
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 very acid soils before planting legumes. Test the soil every two or three years.
A soil test is the surest check for any winged bean 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 sigarilyas needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick sigarilyas, 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
Winged bean nutrient deficiency questions
Why are my sigarilyas leaves turning yellow?
What fertilizer fixes phosphorus deficiency in winged bean?
What fertilizer fixes nitrogen deficiency in winged bean?
What fertilizer fixes potassium deficiency in winged bean?
How do I know which nutrient my sigarilyas lacks?
Find the missing nutrient and fix it
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