29 Chapters
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Rice (Oryza sativa Linn.)

Kumar, P.; Sharma, M.K. CAB International PDF

RICE (Oryza sativa Linn.)

NITROGEN (N) DEFICIENCY

Symptoms

Plate 64. Deficient pale green rice field (foreground) and a healthy dark field (background).

(Photo by Dr Prakash Kumar.)

1. Deficient plants appear stunted, thin and spindly with pale green to yellowish green leaves. The number of tillers and grain yields are reduced severely.

2. Nitrogen is mobile in plants and under short supply conditions it is easily mobilized from older to younger leaves.

3. The deficiency symptoms appear first and become more severe on older leaves (Plate 63).

4. If deficiency occurs during the young stage of the crop, the whole plant appears uniformly pale green to yellowish green. The deficient rice field gives a clear impression of nitrogen deficiency by providing a yellowish green look to the entire crop (Plates 64 and 65).

5. In later stages of the crop, older leaves become pale yellow while younger leaves remain green.

6. A pale yellow chlorosis develops at the tip of old leaves and proceeds in a broad front towards the leaf base.

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Castor (Ricinus communis Linn.)

Kumar, P.; Sharma, M.K. CAB International PDF

CASTOR (Ricinus communis Linn.)

NITROGEN (N) DEFICIENCY

Symptoms

Plate 412. Field view of a nitrogen-deficient castor crop. (Photo by Dr Prakash Kumar.)

1. Nitrogen deficiency decreases leaf area and photosynthesis of castor plants, leading to lower biomass accumulation.

2. High NH4+ concentration in the plant greatly restricts growth.

3. Under deficient conditions, plant growth is retarded remarkably. The leaf dry weight is reduced greatly. The root/shoot ratio is increased.

4. When nitrogen supply is reduced, the deficiency symptoms tend to occur first on lower leaves (Plate 413).

5. The old leaves become pale green to pale yellow while the younger leaves remain normal green (Plate 412).

Developmental stages

Stage I: In mild deficiency conditions, the entire plant may appear light green, having a more pronounced effect on older leaves.

Stage II: Under prolonged deficiency conditions, the lower leaves turn uniformly light yellow (Plate 413).

Stage III: As the symptoms advance, the lower leaves become dark yellow (Plate 411).

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Potato (Solanum tuberosum Linn.)

Kumar, P.; Sharma, M.K. CAB International PDF

POTATO (Solanum tuberosum Linn.)

NITROGEN (N) DEFICIENCY

Symptoms

1. The entire plant may become light green to pale yellow in appearance (Plate 640).

2. Nitrogen is mobile within plants and it is readily mobilized from older to younger tissues when nitrogen supply to the plant is restricted.

3. The deficiency symptoms appear primarily on older leaves and then move to the younger leaves.

4. Older leaves become uniformly yellow while young leaves may remain light green (Plate 641).

5. In prolonged deficiency, yellow older leaves turn dark yellow then brown.

6. Eventually, the leaves become necrotic then dry and fall off early.

Plate 640. Entire plant pale green and stunted.

(Photo by Dr Prakash Kumar.)

Developmental stages

Stage I: In the early stage or in mild deficiency, the entire plant appears uniformly pale green (Plate 640).

Stage II: When deficiency persists, the older leaves turn uniformly yellow and the upper leaves appear pale green (Plate 641).

Stage III: In severe deficiency, the old leaves turn dark yellow

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Maize (Zea mays Linn.)

Kumar, P.; Sharma, M.K. CAB International PDF

MAIZE (Zea mays Linn.)

NITROGEN (N) DEFICIENCY

Symptoms

Plate 24. Young stage nitrogen-deficient crop.

(Photo by Dr Prakash Kumar.)

1. Maize is highly sensitive to nitrogen deficiency. Deficiency symptoms appear even in mild deficiency conditions. Nitrogendeficient plants are stunted with thin, spindly stems and pale green to yellow leaves. Deficient plants produce hardly one small ear per plant and the ears have hardly any grains with reduced kernel size, resulting in a drastic reduction in crop yield.

2. Nitrogen is mobile in plants and under short supply conditions it is easily mobilized from older to younger leaves. The deficiency symptoms appear first and become more severe on older leaves (Plate 23).

3. If deficiency occurs during the young stage of the crop, the whole plant appears uniformly pale green to yellow (Plate 24). In later stages of the crop, older leaves become pale yellow while young leaves remain green.

4. If deficiency persists or occurs in a more mature crop stage, a pale yellow chlorosis develops at the tip of old leaves and proceeds towards the leaf base along the midrib in a V-shaped pattern

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Cotton (Gossypium hirsutum Linn.)

Kumar, P.; Sharma, M.K. CAB International PDF

COTTON (Gossypium hirsutum Linn.)

NITROGEN (N) DEFICIENCY

Symptoms

Plate 584. Entire plant appearing light green and stunted. (Photo by Dr Prakash Kumar and Dr Manoj Kumar Sharma.)

1. Deficient plants appear stunted with short, thin stems.

2. A bright red pigmentation often develops on the lower parts of the stem.

3. The entire plant exhibits a light green appearance (Plate 584).

4. Younger leaves become smaller in size and the number of branches is reduced.

5. Nitrogen is a mobile nutrient in plants and it is rapidly moved from older to younger parts of the plants when its supply is reduced.

6. The deficiency symptoms appear primarily on older leaves and become more severe with time (Plates 583 and 585).

7. Initially, old leaves become pale green, then yellow and finally develop brown necrosis, usually in interveinal regions.

8. Eventually, the affected leaves die and fall off early.

Developmental stages

Stage I: In mild deficiencies, the entire plant appears uniformly light green in colour (Plate 584).

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