Researches of soil fertilization and top dressing in pear orchards (literature review)

Abstract

Biological, meteorological and agro-technical factors have an impact on the nutrition level of fruit and berry crops. To reach high productivity, agricultural crops are to be provided with nutrient substances in a proper form and optimal amount. The addition of important components at critical stages of the plant development gives an impulse to create high and quality yield. Fertilization is aimed at satisfying the feeding needs of the trees in certain soil-climatic conditions; the dose is determined for separate elements according to the peculiarities of a fruit crop, a pomological cultivar, a rootstock and a tree age, also mineral nutrition elements in the soil and the possibility for a fruit crop to use them are taken into consideration. The nutrient requirements of fruit trees vary during the growing season. From the moment of budding to flowering, the need for nitrogen increases, the need for potassium and phosphorus constantly increases during the growing season. Rational mineral fertilization in pear-tree orchards should be based on the results of the soil and leaf analyses as well as on a visual estimation of the growth and fruit bearing of the trees (for example, nitrogen, iron). Unfortunately, it is very common for gardens to be fertilized blindly, without controlling the nutrient content of the soil. Excessive fertilization can both decrease fruit yielding capacity and quality and pollute the environment because of the accumulation of fertilizers in the soil and their washing out into soil and surface waters. The survey of literature sources concerning the effect of soil fertilization and top dressing on the growth and general productivity of pear-tree orchards was made. As a result of the analysis made, it has been established that at present no recommendation as to the application of fertilization in pear-tree orchards is available, because most of them were suggested for apple-tree and pear-tree orchards together. However, there is a difference in mineral nutrition of a pear-tree, in particular those on weak rootstock. Which is why, it is relevant to consider the issue of the development of an optimal fertilization system of intensive pear-tree orchards on a vegetative rootstock