Rubber Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It
Rubber nutrient deficiency is one of the first things to check when the leaves of your goma (rubber) turn yellow, purple or burnt at the edges. On Philippine farms the usual ones are nitrogen, potassium, magnesium, phosphorus and zinc. 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, potassium, magnesium and phosphorus move inside the plant, so a shortage shows on the old, lower leaves first. But zinc 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 rubber nutrient deficiency you have, and a soil test confirms it. Each one below has its signs, its causes and its fix.
Rubber 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 | Leaves of the lower storeys turn evenly pale yellow green, worst on leaves in full sun, and the canopy stays thin. | Complete 14 14 14, Urea 46 0 0 |
| Potassium | old, lower leaves, leaf edges and tips | Old leaves yellow at the tips and edges, then the edges die brown. Leaves come out smaller. | Muriate of potash 0 0 60, Complete 14 14 14 |
| Magnesium | old, lower leaves, between the veins | Old leaves in the lower storeys yellow between the veins, the yellow moving in from the edge while the veins stay green. | Magnesium sulfate (Epsom salt), Kieserite |
| Phosphorus | young leaves and the tip | Bronzing under part of the leaf, often on one half and at the far end, with dying leaf tips and early leaf fall. | Superphosphate 0 20 0, Complete 14 14 14 |
Shows first on the young leaves
| Nutrient | Where it starts | What you see | Fix with |
|---|---|---|---|
| Zinc | young leaves and the tip, between the veins | In young plants, new leaflets come small, narrow, hooked like a claw and wavy edged, with yellow between the veins. | Zinc sulfate |
Before you buy fertilizer for a rubber nutrient deficiency
So use the table to pick the likeliest rubber 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 rubber
The whole leaf turns pale yellow green, then yellow. It shows first on the older leaves of the lower storeys and, when severe, moves up to the young storeys. Leaves in full sun show it more than shaded ones. Young trees grow slowly and the canopy stays small, so trees reach tapping size late. You see it most at this stage: young trees in the first years after planting, and trees under tapping that are never fertilized.
Why nitrogen deficiency happens in goma
Young plantations without fertilizer or cover crops, weedy rows that compete for nitrogen, and leached, eroded soils on slopes.
How to tell it apart
Rubber sheds its leaves once a year (wintering), and leaves turn yellow to orange before they drop. This yearly leaf change is normal, and the whole tree turns at once. To be sure, use basing fertilizer on soil and leaf tests. A soil test also shows how severe it is. Sample leaves from the same storey and age on healthy and pale trees.
What to apply for nitrogen deficiency
Without a test, give Complete 14 14 14 at 125 grams per tree in the first year, 250 grams in the second. 500 grams in the third and fourth years, split into two doses six months apart, spread in a ring 30, 60, 90 and 120 cm from the trunk as the tree grows. Trees under tapping need about 200 grams of Urea 46 0 0 per tree each year, given with potash and rock phosphate. For a quick boost, give a urea leaf spray of 10 grams per liter (160 grams in a 16 liter sprayer).
- Complete 14 14 14
- Urea 46 0 0
- Ammonium sulfate 21 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. 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, plant a legume cover crop between rows, keep the tree rings weeded, and fertilize every year. Let a soil test and the crop's color set the season's nitrogen. Keep organic matter up with compost, manure or crop residues.
Potassium deficiency in rubber
Only the older leaves of the lower storeys show it. The tips and edges turn yellow, and then the edges die and turn brown. Leaves get smaller, and in bad cases yellowing between the veins and dead patches spread, leaf stalks and stems shorten, and the bud at the top can die. You see it most at this stage: young trees and trees under tapping.
Why potassium deficiency happens in goma
Sandy and leached soils, heavy rain, and trees fed only nitrogen. Most rubber soils run low in potassium.
How to tell it apart
Magnesium shortage also starts on old leaves, but it yellows between the veins inward from the edge, without the brown edge scorch. Leaf diseases such as Colletotrichum leave spots spread over the blade, not a band along the edge. To be sure, soil and leaf tests.
What to apply for potassium deficiency
Apply Muriate of potash 0 0 60 based on a soil test, in split doses. Give a quick leaf spray of Sulfate of potash at 10 grams per liter (160 grams in a 16 liter sprayer). Trees tapped on virgin bark need about 200 grams of Muriate of potash per tree each year. 150 grams on renewed bark.
- Muriate of potash 0 0 60
- Complete 14 14 14
- Sulfate of potash 0 0 50
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 a complete fertilizer such as 14 14 14 in young trees and straight potash once trees are tapped. Keep cover crops and mulch.
Magnesium deficiency in rubber
Leaves in the lower, older storeys yellow between the veins first. The yellow usually spreads inward from the leaf edge while the veins stay green. In young seedlings and buddings, the yellow patches may sit away from the edge. Leaf size drops only a little, but severe cases bring heavy leaf fall and slow growth. You see it most at this stage: young and mature trees. It is worst toward the end of the rainy season.
Why magnesium deficiency happens in goma
Acid, leached soils low in magnesium, and heavy potash use. Some clones are more sensitive. Clone RRIC 102 is one of them and needs a 25 percent bigger magnesium dose.
How to tell it apart
Potash shortage also starts on old leaves, but scorches the tip and edge brown. Manganese shortage keeps the midrib and main veins as green bands on a pale leaf, but with no dead tips or edges. To be sure, do a soil test, and a leaf test of leaves from the lower storey.
What to apply for magnesium deficiency
Give 50 kg of Magnesium sulfate per hectare for plantations that show the yellowing. On low magnesium soils, add Dolomite to the yearly fertilizer. Give 50 to 75 grams per tree in year one, rising to 150 to 250 grams from year five until tapping. Do not mix dolomite into fertilizer mixes that contain urea. Kieserite is another source. Do not apply magnesium and potash together.
- Magnesium sulfate (Epsom salt)
- Kieserite
- 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, on acid, low magnesium soils give magnesium every year with the fertilizer. Keep potash and magnesium in balance with a soil test. Lime acid soil with Dolomite rather than plain lime.
Phosphorus deficiency in rubber
A bronze color shows on part of the underside of the leaf and is hard to see from the top. It is often limited to one half of the leaf and starts at the far end of the blade. The leaf tip often dies back. The middle and upper layers of the canopy show it first, and many leaves can drop. You see it most at this stage: young trees on poor soils.
Why phosphorus deficiency happens in goma
Old, weathered acid soils that hold phosphorus tightly, and no phosphate at planting. Phosphorus too runs low in most rubber soils.
How to tell it apart
Mites and thrips can also bronze the leaf underside, so check with a hand lens. Potash and magnesium shortage start on the lower, older storeys, not the middle and upper ones. To be sure, soil and leaf tests.
What to apply for phosphorus deficiency
For quick correction, use Superphosphate 0 20 0. For the long term, rock phosphate or bone meal. Mix rock phosphate into the fertilizer, and give trees tapped on virgin bark about 100 grams per tree each year. Give it when the rains begin.
- Superphosphate 0 20 0
- Complete 14 14 14
- Ammonium 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, put phosphate in the planting hole and use a complete fertilizer such as 14 14 14 in the first years. Test the soil every two or three years.
Zinc deficiency in rubber
It shows mostly in young rubber plants in the nursery or the field. New leaves yellow between the veins and come out smaller, both shorter and narrower. Young leaflets look hooked or claw like, the blade can twist, and the edges turn wavy. In bad cases the growing tip dies and side shoots grow from below it. You see it most at this stage: nursery and young field plants.
Why zinc deficiency happens in goma
Soils outside pH 5 to 7.5, and heavy phosphate use, which ties up zinc.
How to tell it apart
Powdery mildew and Colletotrichum leaf disease also twist and spot young leaves. But they leave white powder or dark spots and patches on the leaflets. To be sure, do a soil test. Spray a few plants with zinc to see if the next flush comes out normal. In a soil test, less than 0.8 ppm of zinc is low.
What to apply for zinc deficiency
Give Zinc sulfate at 40 grams per plant to the soil. In severe cases, give a morning leaf spray of Zinc sulfate at 2 grams per liter (32 grams in a 16 liter sprayer) with 2.5 grams per liter of calcium carbonate. Do not apply zinc and phosphate fertilizer at the same time. Give the soil dose at planting or when the rains begin, and sprays on young growth.
- 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, add compost to nursery soil and test nursery and young field soils for zinc. Test the soil every two or three years.
A soil test is the surest check for any rubber 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 goma needs. That saves money, because extra fertilizer is money lost.
Open the Nutrient Deficiency Finder, pick goma, 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
Rubber nutrient deficiency questions
Why are my goma leaves turning yellow?
What fertilizer fixes nitrogen deficiency in rubber?
What fertilizer fixes potassium deficiency in rubber?
What fertilizer fixes magnesium deficiency in rubber?
How do I know which nutrient my goma 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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