Effect of optimized fertilizer on leaf surface and yield of pear trees in repeated cultivation

The results of studies on the effect of optimized fertilization ofpear plantations of the varieties Conferentsia and Osnovianska on morphological changes of the leaf apparatus and the yield of trees grown on dark gray podzolic heavy loamy soil in the Right-Bank Forest-steppe of Ukraine are considered. Under the optimization of mineral nutrition of these pear varieties in the unirrigated plantation, in different age periods of growth and fruiting, a significant increase in the total leaf area, each leafplate and its thickness was observed on the plots of optimized background with the additional introduction of N30 and N30K30. The highest yields of both research pear varieties in the period of fruiting and growth were also provided by additional nitrogen and nitrogen-potassium nutrition with appropriate fertilization on the optimized background. In these cases, there was a significant increase in tree yield compared to the unfertilized, and fertilized with annual application of N90P60K90, where there was a less balanced ratio of N:P:K in plant nutrition, although the total amount of fertilizer was greater. Key words: pear, fertilizer, variety, leaves, harvest, growth periods