Signs of Plant Nutrient Deficiencies

Elemental deficiencies in plants are common but are hard to diagnose without a leaf tissue analysis. Common symptoms may occur when one or a multitude of elements are deficient. Some common signs include:

Deficiency

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Symptoms

Boron (B)

Boron deficiency is a common disorder affecting plants growing in deficient soils and is often associated with areas of high rainfall and leached soils. Boron may be present but locked up in soils with a high pH, and the deficiency may be worse in wet seasons. Symptoms include dying growing tips and bushy stunted growth, hollow stems in broccoli and carrot roots. Extreme cases may prevent fruit set.

deficient plant

Calcium-deficient leaves show necrosis around the base of the leaves. The very low mobility of calcium is a major factor determining the expression of calcium deficiency symptoms in plants. Classic symptoms of calcium deficiency include blossom- end rot of tomato (burning of the end part of tomato fruits), tip burn of lettuce, blackheart of celery and death of the growing regions in many plants. All these symptoms show soft dead necrotic tissue at rapidly growing areas, which is generally related to poor translocation of calcium to the tissue rather than a low external supply of calcium. Very slow growing plants with a deficient supply of calcium may re-translocate sufficient calcium from older leaves to maintain growth with only a marginal chlorosis of the leaves. This ultimately results in the margins of the leaves growing more slowly than the rest of the leaf, causing the leaf to cup downward. Plants under chronic calcium deficiency have a much greater tendency to wilt than non-stressed plants.

Copper (Cu)

Copper-deficient leaves are curled, and their petioles bend downward. Copper deficiency may be expressed as a light overall chlorosis (loss of the normal green coloration of leaves) along with the permanent loss of turgor in the young leaves. Recently matured leaves show netted, green veining with areas bleaching to a whitish grey. Some leaves develop sunken necrotic spots and have a tendency to bend downward.

Iron is needed to produce chlorophyll, hence its deficiency causes yellowing of leaves. Symptoms include leaves turning yellow or brown in the margins between the veins which may remain green, while young leaves may appear to be bleached. Fruit would be of poor quality and quantity. Any plant may be affected, but raspberries and pears are particularly susceptible, as well as most acid-loving plants such as azaleas and camellias.

Magnesium (Mg)

Magnesium deficiency is a plant disorder with two main causes. Magnesium can be easily washed out of light soils in wet seasons or excessive potassium fertiliser usage can cause also Mg to become unavailable to the growing plants. This disorder particularly affects potatoes, tomatoes, apples, currants and gooseberries, and chrysanthemums. Symptoms include, yellowing between leaf veins, which stay green, giving a marbled appearance. This begins with older leaves and spreads to younger growth. Can be confused with virus, or natural ageing in the case of tomato plants. Fruits are small and woody.

Manganese (Mn)

Manganese deficiency is a plant disorder that is often confused with, and occurs with, iron deficiency. Most common in poorly drained soils, also where organic matter levels are high. Manganese may be unavailable to plants where pH is high. Affected plants include onion, apple, peas, French beans, cherry, citrus and raspberry, and symptoms include yellowing of leaves with smallest leaf veins remaining green to produce a ‘chequered’ effect. The plant may seem to grow away from the problem so that younger leaves may appear to be unaffected. Brown spots may appear on leaf surfaces, and severely affected leaves turn brown and wither. Prevention can be achieved by improving soil structure. Do not over-lime.

Molybdenum (Mo)

Molybdenum deficient leaves show some mottled spotting along with some interveinal chlorosis (loss of the normal green coloration of leaves of plants). An early symptom for molybdenum deficiency is a general overall chlorosis, similar to the symptom for nitrogen deficiency but generally without the reddish coloration on the undersides of the leaves.

Nitrogen (N)

Nitrogen deficiency in plants can occur when woody material such as sawdust is added to the soil. Soil organisms will utilise any nitrogen in order to break this down, thus making it temporarily unavailable to growing plants. ‘Nitrogen drawdown’ is more likely on light soils and those low in organic matter content, although all soils are susceptible. Cold weather, especially early in the season, can also cause a temporary shortage. All vegetables apart from nitrogen fixing legumes are prone to this disorder. Symptoms include poor plant growth, leaves are pale green or yellow in the case of brassicas. Lower leaves show symptoms first. Leaves in this state are said to be chlorotic with reduced chlorophyll. Flowering and fruiting may be delayed.

Phosphorous (P)

Phosphorus deficient leaves show some necrotic (dead) spots. As a rule, phosphorus deficiency symptoms are not very distinct and thus difficult to identify. A major visual symptom is that the plants are dwarfed or stunted. Phosphorus deficient plants develop very slowly in relation to other plants growing under similar environmental conditions but without phosphorus deficiency. Phosphorus deficient plants are often mistaken for unstressed but much younger plants. Under severe deficiency conditions there is also a tendency for leaves to develop a blue-grey luster. In older leaves under very severe deficiency conditions a brown netted veining of the leaves may develop.

Potassium (K)

Potassium deficient leaves show marginal necrosis (tip burn), others at a more advanced deficiency status show necrosis in the interveinal spaces between the main veins along with interveinal chlorosis. This group of symptoms is very characteristic of potassium deficiency.

Sulphur (S)

Sulphur deficient leaves show a general overall chlorosis (yellowing) while still retaining some green colour. The veins and petioles show a very distinct reddish colour. The visual symptoms of sulphur deficiency are very similar to the chlorosis found in nitrogen deficiency. However, in sulphur deficiency the yellowing is much more uniform over the entire plant including young leaves. The reddish colour often found on the underside of the leaves and the petioles has a more pinkish tone and is much less vivid than that found in nitrogen deficiency. With advanced sulphur deficiency brown lesions and/or necrotic spots often develop along the petiole, and the leaves tend to become more erect and often twisted and brittle.

Zinc (Zn)

Zinc is required in a large number of enzymes and plays an essential role in DNA transcription. In the early stages of zinc deficiency the younger leaves become yellow and pitting develops in the interveinal upper surfaces of the mature leaves. A typical symptom of zinc deficiency is the stunted growth of leaves, commonly known as “little leaf” and is caused by the oxidative degradation of the growth hormone auxin.

References: Plant Physiology, Fourth Edition by Lincoln Taiz and Eduardo Zeiger and Others

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