सेब की फसल में पोषण की कमी और उसका प्रबंधन

Apple plants/ fruits may exhibit following specific visual symptoms as well as reduction in growth and yield under nutrient stress.

Nutritional Deficiency Symptoms

Nitrogen: Shoots short, thin, upright and spindly, leaves small, normal in shape with pale yellowish green colour in early stage followed by orange, red purple, yellow tints starting with the older leaves, blossoming and fruiting reduced, fruits small with marked reddening and poor storage qualities.

Phosphorus: Shoots short, thin, upright and spindly, leaves small, with dull purple and bronze tints, early defoliation of older leaves, blossoming and fruiting reduced, bud break in spring may be delayed.

Potassium: Growth restricted and branches die back, leaves bluish green with slight marginal and interveinal chlorosis, followed by marginal scorching either brown or greyish brown colour, blossoms heavy in early stages but yields are poor, fruits small with poor quality.

Calcium: Death of the growing points followed by die-back, scorching and upward rolling of leaf margins, margins ragged in appearance with tip leaves being affected first.

Magnesium: Severe defoliation of terminal shoots progressing from base to tip, purple tinting and marginal or interveinal chlorosis of older leaves, leaves and fruit show heavy drops towards the end of growing season.

Sulphur: Growth restricted, stiff, woody, thin and upright, yellowing of the leaves and orange and red tinting with some necrotic spotting between the main veins with tip leaves affected first.

Zinc: Buds along shoots fail to develop, leaves small and narrow (little leaf), distorted, wavy margins and tend to form rosettes at lips of shoots, foliage sparse throughout the tree with somewhat better growth towards the shoots tips than at the lateral nodes and spurs, blossoming and fruiting reduced, fruits small, pointed and misshapen.

Manganese: Die back of twigs and branches, interveinal chlorosis progressing from margins towards midrib with older leaves may be affected before the tip leaves, early defoliation particularly in the top of the tree, fruits colour poorly.

Iron: Die back of the shoots and branches, young leaves show net work of green veins on a yellowish green background, severely affected leaves may be straw yellow, have few if any green veins and may show marginal or tip burning.

Copper: Die back of the shoots with the dead areas curling downwards, wither tip with tip leaves affected first, leaf margins burnt and ragged with some cupping. In milder stages and interveinal chlorosis of growing leaves resembling iron deficiency may occur, rosetting of leaves may occur due to short internodes, defoliation progresses from the tip to the base of the shoots.

Boron: Shoots show multiple buds and rosettes and fail to elongate in a normal manner, die back, bark rough, pitted and split, leaves show thickening, cupping, yellow veining or complete yellowing, corky veins and defoliation, fruits small, misshapen, corky spot or corky core, cracking of fruits.

Nutritional Deficiency Management

Deficiencies of nitrogen, zinc, boron, manganese and calcium elements are common in apple. These deficiencies of nutrients can be ameliorated by applying recommended doses of organic and inorganic fertilizers. However, before application of any fertilizer, the orchardist should consult horticulture experts for obtaining the best results. The doses of organic and inorganic fertilizers recommended for different ages of apple plants of average fertility in Himachal Pradesh are given in table 1.

Table 1. Recommended fertilizer doses for apple

Methods of Fertilizer Application

Major nutrients like NPK should be applied through soil whereas; micronutrients are supplied through foliar sprays. However, where acute deficiency of nitrogen occurs, foliar application of urea (@1% concentration) provides quick recovery.

A). Major Nutrients: 

Fertilizers should be applied to active toot zone. The N & K fertilizers should be broadcasted on the soil surface under the spread of the trees and slightly mixed with the soil. However, P should be applied in bands in root zone. Fertilizers should be applied 30 cm away from the trunk in old trees and should not be applied in too wet or too dry soils. In high rainfall areas with steep slopes where size of the basins is small, band application of coated fertilizers should be preferred over broadcasting. Following points should be taken into account while undertaking fertilization:

1. In rich soils, the fertilizer doses may be halved or regulated on the basis of leaf analysis report and soil analysis report.
2. In orchards with established cycles of one ‘Off’ year and one ‘On’ year, the fertilizer doses should be reduced by 50% during ‘Off’ year.
3. Apply FYM during December-January along with phosphorus and potash.
4. Apply half dose of nitrogen, 2-3 weeks before flowering and remaining half dose one month after the first application.
5. For better colour development and other quality attributes, foliar spray of 1.5% potassium sulphate (15g/l water) should be sprayed at two stages during fruit development at an interval of 21 days.
6. In soils with alkaline reaction (pH > 8) or acidic reaction (pH < 6) phosphorous dose should be increased by 20%.
7. For areas experiencing continuous drought during early summer, second dose of nitrogen should be avoided. Apply in a single dose along with phosphorous and potassium. In case full dose of N is not applied, then second dose of nitrogen can also be substituted by one to two foliar sprays of urea @ 0.5% (500 g/100 l water) after fruit set.
8. Since the response to phosphorus application is poor, therefore its excessive application should be avoided. It would be a better practice if phosphorus is applied after every two years or alternate years. Apply Rajphos @ 4 times the recommended dose of phosphorous in conjunction with FYM once in 4 years.
9. Give two sprays of calcium chloride @ 0.5%, 45 and 30 days before harvesting fruits to improve the storability of fruits.
10. In heavily bearing orchards, 1% urea should be sprayed immediately after harvest along with Blitox/Copper Oxy chloride @ 0.3% (300 g/100 l water).
11. Pre leaf fall application of 5% urea (5kg/100 l water) should be given for quick defoliation and improved fruit set next year.
12. Bio fertilizers Azotobacter, PSB or AMF (Arbuscular Mycorrizal Fungi) mixed culture may be applied @ 1.0 g each/kg of fully decomposed FYM.
13. For nursery plantation; prepare the slurry of gur @ 450g/l water, add Azotobacter or Azospirillum @ 100 g in this slurry and dip the seedlings for 1-2 minutes. Plant them immediately or dry in shade before planting.

B). Micronutrients

Foliar application of micronutrients should be given after petal fall as given in table 2.

Table 2. Recommended micronutrient foliar doses

In addition to traditional methods of fertilizer application discussed above, use of more advanced and efficient technologies like fertigation employing water soluble/liquid fertilizers is becoming more and more popular especially in commercial fruit production.

Improvement in Production and Quality

For improvement in production and quality of Red Delicious apples, spray Biozyme Fruit Liquid @ 1.5 ml/l water at pink bud stage, petal fall stage and fruit setting stage (25 days after 2^nd spray) or Biovita @ 1.5 ml/l water at pink bud stage, peanut fruit size stage, walnut  fruit size stage and 20 days before harvest or Paushak @ 2.0 ml/l water at silver tip stage, fruit setting (peanut size) stage and walnut fruit size stage or Boon HB-I @ 4.0 ml/l water at pink bud stage, pea nut stage, 30-days after 2^nd application, 30-days after 3^rd application and at the time of fruit maturation. Soil application of 10 kg Celrich Organic Manure at the time of  manuring + 500 g plant Herbozyme-Granule at pink bud and walnut stage + foliar application Herbozyme-Liquid @ 2ml/l water at pink bud and walnut stages also improve growth and enhances production of quality Red Delicious apples. In addition, some commercial formulations containing both macro and micronutrients such as Multiplex, Agromin, Tracel, Planton, Bahar spray, Himset, Octon, micro-nutrients Pushti, Macroliq etc. are available in the market and can be used on the basis of soil/leaf analysis and after consulting experts.

Authors

Sanjeev K. Chaudhary, Neeraj Kotwal and Nirmal Sharma

Regional Horticultural Research Sub Station-Bhaderwah, SKUAST-Jammu (J&K)-182222.

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