Suggestions from the Academy and Research: Fertilizer Application in Apple, its Timing and Importance

Suggestions from the Academy and Research: Fertilizer Application in Apple, its Timing and Importance
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Apple is the economic backbone of state of Jammu and Kashmir, particularly the Kashmir division. The past two decades have witnessed a tremendous spread of apple orchards in Kashmir division of Jammu and Kashmir because apple cultivation fetches more income to the farmers than any other crop in the valley given its market value and demand which is continuously ascending. Through apple cultivation, although, the net gain of the farmers is higher than any other cultivated crop, but certain malpractices and lack of proper training for skill enhancement among apple growers, the production of the crop is not up to the mark.
These malpractices could have been corrected by the Sher-I-Kashmir University of Agricultural Sciences and Technology (SKUAST) and the skill enhancement programs could have been undertaken by the Directorate of Horticulture from time-to-time, depending upon the need but in spite of the heavy investment in both the institutions, they are like bears asleep. A major malpractice lies in the application of fertilizers and its right time. A fertilizer is any material of natural or synthetic origin that is applied to soils or to plant tissues to supply one or more plant nutrients essential for the growth of plants. These fertilizers may be natural or industrially produced. Natural fertilizers include left out organic materials like household wastes, cow dung, poultry and agricultural wastes etc, that have been properly decomposed. The industrially produced fertilizers are generated through different chemical reactions.
Apple trees are fertilized to ensure continued growth and healthy fruit production. Right and judicious application of fertilizers in the orchard helps to maintain the healthy growth and the productivity of the apple tree. The amount of fertilizers to be applied can be gauged by a variety of factors, primary among which include, monitoring the skin of apple tree, the color of leaves, extent of shoot growth as well as by soil analysis. Application of fertilizers should, strictly, be based upon soil analysis carried out routinely for which facilities are made available by the Department of Horticulture.
A major reason for the ‘bad apple crop’ is the lack of proper knowledge among the growers about the right amount and time of the application of the fertilizers. Apple trees, like any other trees require nutrients to live, grow and produce crops. Due to a deficiency of one or more of the nutrients in the soil, the growth and productivity of the crop is highly affected, which in turn results in the trees being prone to diseases and pests, decreasing the normal life span than a well fertilized tree. Nutrient requirement, required by most of the trees can be broadly divided into two major categories: macro and micronutrients.
This classification is based upon the quantity of nutrients necessary for survival and growth. Macronutrients are required by plants in greater quantities than micronutrients. The macronutrients required by plants for growth include nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). The addition of macronutrients, especially nitrogen, can result in improved growth while deficiencies can lead to slower growth and many visible symptoms like yellowing of leaves, stunted growth etc. Micronutrients, which are required in very small amounts, include iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), chlorine (Cl), and molybdenum (Mo). Scientific research proves that plant growth cannot occur until supplied with mineral nutrients required in least amounts, thus necessitating the use of micronutrients which are otherwise omitted.
It is hereby suggested to apple growers to keep a constant watch upon the trees to ensure proper fertilization. The imperative is to carry fertilization in three stages. Firstly, the mature apple trees must be supplied with fertilizers just before or just after bud break (Early Spring fertilization) which usually occurs between last week of February and second week of March. It is the best time to fertilize the trees as the flowers begin to sprout in the apple trees. The second fertilization should be done in early summer, between last week of May to third week of June by properly monitoring the apple tress in terms of any visible deficiency which includes leaf curling and yellowing, reduced leaf growth and fruit size or by looking at the growth of tree. Late fertilizing in summer inhibits the tree’s ability to stay hydrated. Finally, post- harvest fertilization should essentially be carried out between the last week of the September and third week of October, as in the new season, apple and other deciduous trees rely on the nutrients stored from the previous autumn for flowering and for development of new leaves. Post-harvest fertilizer applications are often beneficial as they ensure adequate nutrient storage for the following spring. After harvest, there is decline in water uptake which is reduced to nil after leaf fall. This necessitates applying fertilizer just after harvest and if applied lately, winter rainfall will leach away the fertilizer residues from the soil. Application of fertilizers after leaf fall is a futile as the apple trees are entering a dormant stage and a period of metabolic arrest.
The apple trees must also be supplemented with right amounts of natural or organic fertilizers which are beneficial for the maintenance of the health of soils. Winters or dormancy is the best time to apply manure than chemical fertilizers. The soil must be dusted with 1 to 2 inches of well rotted-manure in February while the tree is still dormant and again in June when there is highest metabolic activity. The type and kind of manure is hardly an issue (horse, chicken, cow, sheep or goat excretory wastes) but it needs to be well rotten. Well rotten manure is odourlesss and resembles black soil. Well rotten manure is environment friendly organic fertilizer and adds nitrogen, potassium and other nutrients to the soils. It also adds organic matter that helps loosen the soil, increases the oxygen content, attracts earthworms and increases useful bacteria in the soil. The use of fresh manure is hazardous and must be avoided as it liberates high ammonia, which can give root burns and can damage trees.

The author is an Assistant Professor (Botany) at GDC, Kulgam and can be reached