Prof. (Dr) R.D. Gupta
Apple being one of the most important temperate fruit, is mostly grown in Jammu and Kashmir, Himachal Pradesh and Uttrakhand, and to some extent in north eastern hill states like Arunachal Pradesh, Sikkim, Nagaland etc. like food grain crops, apple and other fruit trees also require all the essential plant nutrients, which consist both of macro-N, P, K, Ca, Mg, S and micro-Fe, Cu, Mn, Zn, B, Mo and Cl. The amount of these plant nutrients are taken from the soils by this fruit tree like others which varies according to its variety nature of the soil and its slope vis-à-vis water management practices etc.
Nitrogen (N): It is one of the major mineral plant nutrients which tackles the growth and yield of the fruit trees and, thus, imparts a good response to this nutrient. Its deficiency symptoms appear in older leaves, which usually show nitrogen content less than 1.89%. The affected leaves get reduced in size with yellowish colour at the base of leaf during early stages of growth two the sprays of 1% urea during active growing season at 7 days interval on the appearance of visual deficiency have been found effective in controlling the aforesaid symptoms. Spray should be done during early morning hours or evening.
Phosphorus (P): Phosphorus is generally obtained from soils in the early stages when the trees have formed intensive root system. Acute deficiency of P in the apple tree results in slender shoot growth with upright leaf petioles. The leaves are smaller than normal and remain dark green with reddish or purplish tinting of the midrib and larger veins. The interveinal areas of leaves become bronzed in appearance. Apple trees growing on low available P soils are of low vigour with stunted growth and production of inferior quality fruit. The deficient leaves become violet to purple in colour and the deficiency occurs mostly in older leaves. The emergence of bud gets delayed and deficiency usually appears in those apple trees which have P in the range of 0.10 to 0.13% in their leaves. Apply 150g of P per tree in the form of DAP (330g) for a tree having more than 10 years of age.
Potassium (K): Potassium improves the quality of apple especially colour and plants can withstand water stress especially in soils of Karewas of Kashmir where already prevails water scarcity. Besides playing significant role in regulating transpiration and water-conditions in the plant cell, it also acts as an activator for a number of enzyme systems.
Apple leaves generally show chlorotic mottling between veins and marginal scorching of older leaves. Its deficiency has been observed in those soils whence four or five crops had been harvested. A slight chlorosis sometimes preceded the actual scorching. There is collapse of well grown trees. Such trees appeared normal in early summer but started showing severe scorching within week’s time and get died the same season. The deficient plants contained 1.00 to 1.49% K in their leaves. Addition of 670 g MOP per tree should be applied along with DAP.
Calcium (Ca): As the mobility of Ca is low, so its deficiency can be seen in younger leaves. The trees revealing deficiency have Ca in their leaves to less than 1.2 %. In Ca deficient plants the terminal ends become dark brown which later on turn into dark black and finally necrotic. Its deficiency can be removed by applying CAN instead of urea @ 1 Kg tree. It should be added 60-100 cm away from the trunk in the basin and thoroughly mixed in the soil.
Magnesium (Mg): Since Mg is essential for chlorophyll formation, hence its deficiency is revealed by localized destruction of this pigment and usually there is “V shaped” interveindous discoloration of older leaves. Deficiency occurs in trees having less than 0.25 % Mg in their leaf samples. Application of magnesium sulphate @ 1-2 Kg per tree about 2-3 weeks before flowering checks its deficiency.
Sulpher (S): It is a constituent of protein in the form of S-bearing amino acids like cystine and methionine. Common deficiency symptoms are burning of young leaves to a pale green colour. The leaves showing S-deficiency have less than 0.1% S in dry matter. Application of gypsum @ 1-2 Kg per tree can check its deficiency.
Zinc (Zn): As Zn is not readily translocated from the old to new leaves hence its deficiency symptoms appear in new leaves. Shortening of the stem into nodes and restriction of leaf size, and rosette appearance of leaves are the other symptoms of Zn deficiency in apple trees. Zinc is necessary for the synthesis oftryptophan, a precursor of indole acetic acid which acts as growth hormone. Application of 20-25 Kg Zn SO4 per ha to soil would be enough to correct Zn deficiency. However, if deficiency symptoms in apple appear at later stage than spray 1% solution of Zn SO4 (1% Zn SO4) to 0.75 Kg hydrated lime. This spray should be done when apple trees have enough foliage. Usually leaves having less than 10 ppm Zn are considered deficient in this nutrient.
Boron (B): Deficiency of B is noticed in those apple orchards where its content lies between 30 and 34 ppm in their leaves. Visible symptoms of B deficiency are death of shoot tips. Leaves become thick textured sometimes there is curling and get turn into quite brittle. Generally flowers do not form and root growth is stunted. There is disintegration of the internal tissues which results in abnormalities such as internal cork formation in apple fruits. Soil application of borax @ 75-150 g per tree per year has been found effective in controlling the deficiency. It should be applied at the time of dormancy (End of December or mid of January).
Future Strategies
Although the author has not been able to observe Fe and Mn deficient apple plants in the Kashmir valley during the survey conducted by him in the years 2010 and 2011 yet there are reports from Uttrakhand and Himachal Pradesh with regard to their deficiency. Hence more studies are required to be carried out in this aspect.
The apple orchardists are required to apply fertilizers on the basis of soil test. For this purpose, they should have contact with the scientists of Soil Testing Laboratories which are under the Department of Agriculture where the soil testing is done free of cost.
To have complete picture of mineral nutrients of apple orchards detailed studies of leaf samples analysis is also required to be done.
Whichever organic manure is available with the orchardists, it must be applied during the month of December or January. It will take care of macro as well as micronutrients deficiency to some extent and also help in stabilizing the pH of the soils.
While adding organic manures, the orchardists must ensure that their manure is well decomposed one. Well decomposed nature of the organic manure can be judged when it is dark brown or black in colour and amorphous in character.
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