29 Chapters
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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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Sugarcane (Saccharum officinarum Linn.)

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

SUGARCANE (Saccharum officinarum Linn.)

NITROGEN (N) DEFICIENCY

Symptoms

Plate 612. Die-back of an old leaf.

(Photo by Dr Manoj Kumar Sharma.)

1. In the nitrogen-deficient crop, stalks become short and slender

(Plate 614).

2. Fewer tillers are produced and overall growth of the plant is reduced.

3. The entire plant may become light green in appearance.

4. Nitrogen is a mobile nutrient in plants and in poor supply conditions it is easily mobilized from older to younger leaves.

5. The deficiency symptoms are primarily observed on older leaves (Plate 611).

6. Later, the entire plant turns chlorotic.

7. Older leaves may become uniformly pale green to yellow

(Plate 611).

8. Nitrogen deficiency causes die-back of older leaves (Plates 612 and 613).

9. Necrosis occurs on the tips and margins of recently matured old leaves.

Developmental stages

Stage I: In the early plant stage or mild deficiency, the entire plant appears uniformly light green.

Stage II: In prolonged deficiency, the older leaves turn uniformly yellow to dark yellow (Plate 611).

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2 How to Identify Plant Nutrient Deficiencies in Field Conditions

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

2

How to Identify Plant Nutrient

Deficiencies in Field Conditions

Prakash Kumar

Visual Diagnosis and Difficulties

The term ‘clinical diagnosis’ is used in medical sciences to describe the way of diagnosis based on the appearance of the clinical symptoms, without any laboratory tests or X-ray films. In the process of clinical diagnosis, the practising doctor matches the appearing clinical symptoms of the patient with the symptoms of the diseases known to him and makes a preliminary idea of the probable disease. Then, the doctor suggests some laboratory tests to verify the disease. After confirmation, the treatment is prescribed. Though the clinical diagnosis is a preliminary assumption by the doctor, it is a very important observation as only this provides the right direction to the tests and treatments. Therefore the clinical diagnosis is the most essential skill of a doctor, which is based on his/her ‘knowledge’ and ‘experience’. At times, experienced doctors are so sure and confident that they prescribe the treatment without any laboratory test.

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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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1 An Introduction to Plant Nutrition

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

1

An Introduction to Plant Nutrition

Manoj Kumar Sharma

The biggest challenge for agriculture over the coming decades will be to meet the world’s increasing demand for food in a sustainable manner. Therefore, our goal will be to produce more to feed the growing population. In order to achieve this uphill task, there are two options before us. The first option is to bring more land under cultivation and the second option is to increase production per unit cultivated area by adopting intensive cultivation. Because of the continuous increasing demand on land for other developmental activities, the scope for increasing cultivated area is limited. Accordingly, greater attention will have to be paid to increase the production per unit area of cultivated land by adopting exhaustive use of agricultural inputs.

Deteriorating soil fertility and improper management of plant nutrients have further aggravated the problem. Large increases in productivity cannot be attained without ensuring that plants are supplied with adequate and balanced nutrition. Soils are the storehouse of most of the plant nutrients essential for plant growth and development and the way in which nutrients are managed will have a great impact on plant growth, soil fertility and agricultural sustainability. Plant growth is considered the result of a complex process by which the plant synthesizes food by using solar energy, carbon dioxide, water and nutrients from the soil.

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